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vhdl/Common/sim/ieee_proposed/modelsim/float_pkg_c.vhdl
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jens c229af0f71 - added ieee_proposed 
git-svn-id: http://moon:8086/svn/vhdl/trunk@1304 cc03376c-175c-47c8-b038-4cd826a8556b
2015-10-23 04:43:48 +00:00

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-- --------------------------------------------------------------------
-- "float_pkg" package contains functions for floating point math.
-- Please see the documentation for the floating point package.
-- This package should be compiled into "ieee_proposed" and used as follows:
-- use ieee.std_logic_1164.all;
-- use ieee.numeric_std.all;
-- use ieee_proposed.math_utility.all;
-- use ieee_proposed.fixed_pkg.all;
-- use ieee_proposed.float_pkg.all;
--
-- This verison is designed to work with the VHDL-93 compilers. Please
-- note the "%%%" comments. These are where we diverge from the
-- VHDL-200X LRM.
--
-- --------------------------------------------------------------------
-- Version : $Revision: 1.9 $
-- Date : $Date: 2007-04-04 13:59:52-04 $
-- --------------------------------------------------------------------
use STD.TEXTIO.all;
library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.NUMERIC_STD.all;
library ieee_proposed;
use ieee_proposed.math_utility_pkg.all;
use ieee_proposed.fixed_pkg.all;
package float_pkg is
-- generic (
-- Defaults for sizing routines, when you do a "to_float" this will be
-- the default size. Example float32 would be 8 and 23 (8 downto -23)
constant float_exponent_width : NATURAL := 8;
constant float_fraction_width : NATURAL := 23;
-- Rounding algorithm, "round_nearest" is default, other valid values
-- are "round_zero" (truncation), "round_inf" (round up), and
-- "round_neginf" (round down)
constant float_round_style : round_type := round_nearest;
-- Denormal numbers (very small numbers near zero) true or false
constant float_denormalize : BOOLEAN := true;
-- Turns on NAN processing (invalid numbers and overflow) true of false
constant float_check_error : BOOLEAN := true;
-- Guard bits are added to the bottom of every operation for rounding.
-- any natural number (including 0) are valid.
constant float_guard_bits : NATURAL := 3;
-- If TRUE, then turn off warnings on "X" propagation
constant no_warning : BOOLEAN := (false
);
-- Author David Bishop (dbishop@vhdl.org)
-- Note that the size of the vector is not defined here, but in
-- the package which calls this one.
type UNRESOLVED_float is array (INTEGER range <>) of STD_ULOGIC; -- main type
subtype U_float is UNRESOLVED_float;
subtype float is UNRESOLVED_float;
-----------------------------------------------------------------------------
-- Use the float type to define your own floating point numbers.
-- There must be a negative index or the packages will error out.
-- Minimum supported is "subtype float7 is float (3 downto -3);"
-- "subtype float16 is float (6 downto -9);" is probably the smallest
-- practical one to use.
-----------------------------------------------------------------------------
-- IEEE 754 single precision
subtype UNRESOLVED_float32 is UNRESOLVED_float (8 downto -23);
alias U_float32 is UNRESOLVED_float32;
subtype float32 is float (8 downto -23);
-----------------------------------------------------------------------------
-- IEEE-754 single precision floating point. This is a "float"
-- in C, and a FLOAT in Fortran. The exponent is 8 bits wide, and
-- the fraction is 23 bits wide. This format can hold roughly 7 decimal
-- digits. Infinity is 2**127 = 1.7E38 in this number system.
-- The bit representation is as follows:
-- 1 09876543 21098765432109876543210
-- 8 76543210 12345678901234567890123
-- 0 00000000 00000000000000000000000
-- 8 7 0 -1 -23
-- +/- exp. fraction
-----------------------------------------------------------------------------
-- IEEE 754 double precision
subtype UNRESOLVED_float64 is UNRESOLVED_float (11 downto -52);
alias U_float64 is UNRESOLVED_float64;
subtype float64 is float (11 downto -52);
-----------------------------------------------------------------------------
-- IEEE-754 double precision floating point. This is a "double float"
-- in C, and a FLOAT*8 in Fortran. The exponent is 11 bits wide, and
-- the fraction is 52 bits wide. This format can hold roughly 15 decimal
-- digits. Infinity is 2**2047 in this number system.
-- The bit representation is as follows:
-- 3 21098765432 1098765432109876543210987654321098765432109876543210
-- 1 09876543210 1234567890123456789012345678901234567890123456789012
-- S EEEEEEEEEEE FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
-- 11 10 0 -1 -52
-- +/- exponent fraction
-----------------------------------------------------------------------------
-- IEEE 854 & C extended precision
subtype UNRESOLVED_float128 is UNRESOLVED_float (15 downto -112);
alias U_float128 is UNRESOLVED_float128;
subtype float128 is float (15 downto -112);
-----------------------------------------------------------------------------
-- The 128 bit floating point number is "long double" in C (on
-- some systems this is a 70 bit floating point number) and FLOAT*32
-- in Fortran. The exponent is 15 bits wide and the fraction is 112
-- bits wide. This number can handle approximately 33 decimal digits.
-- Infinity is 2**32,767 in this number system.
-----------------------------------------------------------------------------
-- purpose: Checks for a valid floating point number
type valid_fpstate is (nan, -- Signaling NaN (C FP_NAN)
quiet_nan, -- Quiet NaN (C FP_NAN)
neg_inf, -- Negative infinity (C FP_INFINITE)
neg_normal, -- negative normalized nonzero
neg_denormal, -- negative denormalized (FP_SUBNORMAL)
neg_zero, -- -0 (C FP_ZERO)
pos_zero, -- +0 (C FP_ZERO)
pos_denormal, -- Positive denormalized (FP_SUBNORMAL)
pos_normal, -- positive normalized nonzero
pos_inf, -- positive infinity
isx); -- at least one input is unknown
-- This deferred constant will tell you if the package body is synthesizable
-- or implemented as real numbers.
constant fphdlsynth_or_real : BOOLEAN; -- deferred constant
-- Returns the class which X falls into
function Classfp (
x : UNRESOLVED_float; -- floating point input
check_error : BOOLEAN := float_check_error) -- check for errors
return valid_fpstate;
-- Arithmetic functions, these operators do not require parameters.
function "abs" (arg : UNRESOLVED_float) return UNRESOLVED_float;
function "-" (arg : UNRESOLVED_float) return UNRESOLVED_float;
-- These allows the base math functions to use the default values
-- of their parameters. Thus they do full IEEE floating point.
function "+" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "-" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "*" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "/" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "rem" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "mod" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
-- Basic parameter list
-- round_style - Selects the rounding algorithm to use
-- guard - extra bits added to the end if the operation to add precision
-- check_error - When "false" turns off NAN and overflow checks
-- denormalize - When "false" turns off denormal number processing
function add (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function subtract (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function multiply (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function divide (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function remainder (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function modulo (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- reciprocal
function reciprocal (
arg : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function dividebyp2 (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- Multiply accumulate result = l*r + c
function mac (
l, r, c : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- Square root (all 754 based implementations need this)
function sqrt (
arg : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style;
constant guard : NATURAL := float_guard_bits;
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_float;
function Is_Negative (arg : UNRESOLVED_float) return BOOLEAN;
-----------------------------------------------------------------------------
-- compare functions
-- =, /=, >=, <=, <, >, maximum, minimum
function eq ( -- equal =
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN;
function ne ( -- not equal /=
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN;
function lt ( -- less than <
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN;
function gt ( -- greater than >
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN;
function le ( -- less than or equal to <=
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN;
function ge ( -- greater than or equal to >=
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN;
-- Need to overload the default versions of these
function "=" (l, r : UNRESOLVED_float) return BOOLEAN;
function "/=" (l, r : UNRESOLVED_float) return BOOLEAN;
function ">=" (l, r : UNRESOLVED_float) return BOOLEAN;
function "<=" (l, r : UNRESOLVED_float) return BOOLEAN;
function ">" (l, r : UNRESOLVED_float) return BOOLEAN;
function "<" (l, r : UNRESOLVED_float) return BOOLEAN;
function \?=\ (l, r : UNRESOLVED_float) return STD_ULOGIC;
function \?/=\ (l, r : UNRESOLVED_float) return STD_ULOGIC;
function \?>\ (l, r : UNRESOLVED_float) return STD_ULOGIC;
function \?>=\ (l, r : UNRESOLVED_float) return STD_ULOGIC;
function \?<\ (l, r : UNRESOLVED_float) return STD_ULOGIC;
function \?<=\ (l, r : UNRESOLVED_float) return STD_ULOGIC;
function std_match (l, r : UNRESOLVED_float) return BOOLEAN;
function find_rightmost (arg : UNRESOLVED_float; y : STD_ULOGIC)
return INTEGER;
function find_leftmost (arg : UNRESOLVED_float; y : STD_ULOGIC)
return INTEGER;
function maximum (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function minimum (l, r : UNRESOLVED_float) return UNRESOLVED_float;
-- conversion functions
-- Converts one floating point number into another.
function resize (
arg : UNRESOLVED_float; -- Floating point input
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function resize (
arg : UNRESOLVED_float; -- Floating point input
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
function to_float32 (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float32;
function to_float64 (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float64;
function to_float128 (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float128;
-- Converts an fp into an SLV (needed for synthesis)
function to_slv (arg : UNRESOLVED_float) return STD_LOGIC_VECTOR;
alias to_StdLogicVector is to_slv [UNRESOLVED_float return STD_LOGIC_VECTOR];
alias to_Std_Logic_Vector is to_slv [UNRESOLVED_float return STD_LOGIC_VECTOR];
-- Converts an fp into an SULV
function to_suv (arg : UNRESOLVED_float) return STD_ULOGIC_VECTOR;
alias to_StdULogicVector is to_suv [UNRESOLVED_float return STD_ULOGIC_VECTOR];
alias to_Std_ULogic_Vector is to_suv [UNRESOLVED_float return STD_ULOGIC_VECTOR];
-- std_ulogic_vector to float
function to_float (
arg : STD_ULOGIC_VECTOR;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width) -- length of FP output fraction
return UNRESOLVED_float;
-- Integer to float
function to_float (
arg : INTEGER;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float;
-- real to float
function to_float (
arg : REAL;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- unsigned to float
function to_float (
arg : UNSIGNED;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float;
-- signed to float
function to_float (
arg : SIGNED;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float;
-- unsigned fixed point to float
function to_float (
arg : UNRESOLVED_ufixed; -- unsigned fixed point input
constant exponent_width : NATURAL := float_exponent_width; -- width of exponent
constant fraction_width : NATURAL := float_fraction_width; -- width of fraction
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- use ieee extensions
return UNRESOLVED_float;
-- signed fixed point to float
function to_float (
arg : UNRESOLVED_sfixed;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- rounding option
return UNRESOLVED_float;
-- size_res functions
-- Integer to float
function to_float (
arg : INTEGER;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float;
-- real to float
function to_float (
arg : REAL;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- unsigned to float
function to_float (
arg : UNSIGNED;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float;
-- signed to float
function to_float (
arg : SIGNED;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float;
-- sulv to float
function to_float (
arg : STD_ULOGIC_VECTOR;
size_res : UNRESOLVED_float)
return UNRESOLVED_float;
-- unsigned fixed point to float
function to_float (
arg : UNRESOLVED_ufixed; -- unsigned fixed point input
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- use ieee extensions
return UNRESOLVED_float;
-- signed fixed point to float
function to_float (
arg : UNRESOLVED_sfixed;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- rounding option
return UNRESOLVED_float;
-- float to unsigned
function to_unsigned (
arg : UNRESOLVED_float; -- floating point input
constant size : NATURAL; -- length of output
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return UNSIGNED;
-- float to signed
function to_signed (
arg : UNRESOLVED_float; -- floating point input
constant size : NATURAL; -- length of output
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return SIGNED;
-- purpose: Converts a float to unsigned fixed point
function to_ufixed (
arg : UNRESOLVED_float; -- fp input
constant left_index : INTEGER; -- integer part
constant right_index : INTEGER; -- fraction part
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_ufixed;
-- float to signed fixed point
function to_sfixed (
arg : UNRESOLVED_float; -- fp input
constant left_index : INTEGER; -- integer part
constant right_index : INTEGER; -- fraction part
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_sfixed;
-- size_res versions
-- float to unsigned
function to_unsigned (
arg : UNRESOLVED_float; -- floating point input
size_res : UNSIGNED;
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return UNSIGNED;
-- float to signed
function to_signed (
arg : UNRESOLVED_float; -- floating point input
size_res : SIGNED;
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return SIGNED;
-- purpose: Converts a float to unsigned fixed point
function to_ufixed (
arg : UNRESOLVED_float; -- fp input
size_res : UNRESOLVED_ufixed;
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_ufixed;
-- float to signed fixed point
function to_sfixed (
arg : UNRESOLVED_float; -- fp input
size_res : UNRESOLVED_sfixed;
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_sfixed;
-- float to real
function to_real (
arg : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return REAL;
-- float to integer
function to_integer (
arg : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return INTEGER;
-- Maps metalogical values
function to_01 (
arg : UNRESOLVED_float; -- floating point input
XMAP : STD_LOGIC := '0')
return UNRESOLVED_float;
function Is_X (arg : UNRESOLVED_float) return BOOLEAN;
function to_X01 (arg : UNRESOLVED_float) return UNRESOLVED_float;
function to_X01Z (arg : UNRESOLVED_float) return UNRESOLVED_float;
function to_UX01 (arg : UNRESOLVED_float) return UNRESOLVED_float;
-- These two procedures were copied out of the body because they proved
-- very useful for vendor specific algorithm development
-- Break_number converts a floating point number into it's parts
-- Exponent is biased by -1
procedure break_number (
arg : in UNRESOLVED_float;
denormalize : in BOOLEAN := float_denormalize;
check_error : in BOOLEAN := float_check_error;
fract : out UNSIGNED;
expon : out SIGNED; -- NOTE: Add 1 to get the real exponent!
sign : out STD_ULOGIC);
procedure break_number (
arg : in UNRESOLVED_float;
denormalize : in BOOLEAN := float_denormalize;
check_error : in BOOLEAN := float_check_error;
fract : out ufixed; -- a number between 1.0 and 2.0
expon : out SIGNED; -- NOTE: Add 1 to get the real exponent!
sign : out STD_ULOGIC);
-- Normalize takes a fraction and and exponent and converts them into
-- a floating point number. Does the shifting and the rounding.
-- Exponent is assumed to be biased by -1
function normalize (
fract : UNSIGNED; -- fraction, unnormalized
expon : SIGNED; -- exponent - 1, normalized
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
constant exponent_width : NATURAL := float_exponent_width; -- size of output exponent
constant fraction_width : NATURAL := float_fraction_width; -- size of output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float;
-- Exponent is assumed to be biased by -1
function normalize (
fract : ufixed; -- unsigned fixed point
expon : SIGNED; -- exponent - 1, normalized
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
constant exponent_width : NATURAL := float_exponent_width; -- size of output exponent
constant fraction_width : NATURAL := float_fraction_width; -- size of output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float;
function normalize (
fract : UNSIGNED; -- unsigned
expon : SIGNED; -- exponent - 1, normalized
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
size_res : UNRESOLVED_float; -- used for sizing only
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float;
-- Exponent is assumed to be biased by -1
function normalize (
fract : ufixed; -- unsigned fixed point
expon : SIGNED; -- exponent - 1, normalized
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
size_res : UNRESOLVED_float; -- used for sizing only
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float;
-- overloaded versions
function "+" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function "+" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function "+" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function "+" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
function "-" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function "-" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function "-" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function "-" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
function "*" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function "*" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function "*" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function "*" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
function "/" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function "/" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function "/" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function "/" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
function "rem" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function "rem" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function "rem" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function "rem" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
function "mod" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function "mod" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function "mod" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function "mod" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
-- overloaded compare functions
function "=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN;
function "/=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN;
function ">=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN;
function "<=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN;
function ">" (l : UNRESOLVED_float; r : REAL) return BOOLEAN;
function "<" (l : UNRESOLVED_float; r : REAL) return BOOLEAN;
function "=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN;
function "/=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN;
function ">=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN;
function "<=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN;
function ">" (l : REAL; r : UNRESOLVED_float) return BOOLEAN;
function "<" (l : REAL; r : UNRESOLVED_float) return BOOLEAN;
function "=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN;
function "/=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN;
function ">=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN;
function "<=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN;
function ">" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN;
function "<" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN;
function "=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN;
function "/=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN;
function ">=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN;
function "<=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN;
function ">" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN;
function "<" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN;
function \?=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC;
function \?/=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC;
function \?>\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC;
function \?>=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC;
function \?<\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC;
function \?<=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC;
function \?=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC;
function \?/=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC;
function \?>\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC;
function \?>=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC;
function \?<\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC;
function \?<=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC;
function \?=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC;
function \?/=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC;
function \?>\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC;
function \?>=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC;
function \?<\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC;
function \?<=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC;
function \?=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC;
function \?/=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC;
function \?>\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC;
function \?>=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC;
function \?<\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC;
function \?<=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC;
-- minimum and maximum overloads
function maximum (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function minimum (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float;
function maximum (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function minimum (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float;
function maximum (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function minimum (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float;
function maximum (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
function minimum (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float;
----------------------------------------------------------------------------
-- logical functions
----------------------------------------------------------------------------
function "not" (l : UNRESOLVED_float) return UNRESOLVED_float;
function "and" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "or" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "nand" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "nor" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "xor" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
function "xnor" (l, r : UNRESOLVED_float) return UNRESOLVED_float;
-- Vector and std_ulogic functions, same as functions in numeric_std
function "and" (l : STD_ULOGIC; r : UNRESOLVED_float)
return UNRESOLVED_float;
function "and" (l : UNRESOLVED_float; r : STD_ULOGIC)
return UNRESOLVED_float;
function "or" (l : STD_ULOGIC; r : UNRESOLVED_float)
return UNRESOLVED_float;
function "or" (l : UNRESOLVED_float; r : STD_ULOGIC)
return UNRESOLVED_float;
function "nand" (l : STD_ULOGIC; r : UNRESOLVED_float)
return UNRESOLVED_float;
function "nand" (l : UNRESOLVED_float; r : STD_ULOGIC)
return UNRESOLVED_float;
function "nor" (l : STD_ULOGIC; r : UNRESOLVED_float)
return UNRESOLVED_float;
function "nor" (l : UNRESOLVED_float; r : STD_ULOGIC)
return UNRESOLVED_float;
function "xor" (l : STD_ULOGIC; r : UNRESOLVED_float)
return UNRESOLVED_float;
function "xor" (l : UNRESOLVED_float; r : STD_ULOGIC)
return UNRESOLVED_float;
function "xnor" (l : STD_ULOGIC; r : UNRESOLVED_float)
return UNRESOLVED_float;
function "xnor" (l : UNRESOLVED_float; r : STD_ULOGIC)
return UNRESOLVED_float;
-- Reduction operators, same as numeric_std functions
function and_reduce (l : UNRESOLVED_float) return STD_ULOGIC;
function nand_reduce (l : UNRESOLVED_float) return STD_ULOGIC;
function or_reduce (l : UNRESOLVED_float) return STD_ULOGIC;
function nor_reduce (l : UNRESOLVED_float) return STD_ULOGIC;
function xor_reduce (l : UNRESOLVED_float) return STD_ULOGIC;
function xnor_reduce (l : UNRESOLVED_float) return STD_ULOGIC;
-- Note: "sla", "sra", "sll", "slr", "rol" and "ror" not implemented.
-----------------------------------------------------------------------------
-- Recommended Functions from the IEEE 754 Appendix
-----------------------------------------------------------------------------
-- returns x with the sign of y.
function Copysign (x, y : UNRESOLVED_float) return UNRESOLVED_float;
-- Returns y * 2**n for integral values of N without computing 2**n
function Scalb (
y : UNRESOLVED_float; -- floating point input
N : INTEGER; -- exponent to add
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- Returns y * 2**n for integral values of N without computing 2**n
function Scalb (
y : UNRESOLVED_float; -- floating point input
N : SIGNED; -- exponent to add
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float;
-- returns the unbiased exponent of x
function Logb (x : UNRESOLVED_float) return INTEGER;
function Logb (x : UNRESOLVED_float) return SIGNED;
-- returns the next representable neighbor of x in the direction toward y
function Nextafter (
x, y : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_float;
-- Returns TRUE if X is unordered with Y.
function Unordered (x, y : UNRESOLVED_float) return BOOLEAN;
function Finite (x : UNRESOLVED_float) return BOOLEAN;
function Isnan (x : UNRESOLVED_float) return BOOLEAN;
-- Function to return constants.
function zerofp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float;
function nanfp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float;
function qnanfp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float;
function pos_inffp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float;
function neg_inffp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float;
function neg_zerofp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float;
-- size_res versions
function zerofp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float;
function nanfp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float;
function qnanfp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float;
function pos_inffp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float;
function neg_inffp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float;
function neg_zerofp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float;
--===========================================================================
-- string and textio Functions
--===========================================================================
-- rtl_synthesis off
-- pragma synthesis_off
-- writes S:EEEE:FFFFFFFF
procedure WRITE (
L : inout LINE; -- access type (pointer)
VALUE : in UNRESOLVED_float; -- value to write
JUSTIFIED : in SIDE := right; -- which side to justify text
FIELD : in WIDTH := 0); -- width of field
-- Reads SEEEEFFFFFFFF, "." and ":" are ignored
procedure READ (L : inout LINE; VALUE : out UNRESOLVED_float);
procedure READ (L : inout LINE; VALUE : out UNRESOLVED_float;
GOOD : out BOOLEAN);
alias BREAD is READ [LINE, UNRESOLVED_float, BOOLEAN];
alias BREAD is READ [LINE, UNRESOLVED_float];
alias BWRITE is WRITE [LINE, UNRESOLVED_float, SIDE, WIDTH];
alias BINARY_READ is READ [LINE, UNRESOLVED_FLOAT, BOOLEAN];
alias BINARY_READ is READ [LINE, UNRESOLVED_FLOAT];
alias BINARY_WRITE is WRITE [LINE, UNRESOLVED_float, SIDE, WIDTH];
procedure OWRITE (
L : inout LINE; -- access type (pointer)
VALUE : in UNRESOLVED_float; -- value to write
JUSTIFIED : in SIDE := right; -- which side to justify text
FIELD : in WIDTH := 0); -- width of field
-- Octal read with padding, no separators used
procedure OREAD (L : inout LINE; VALUE : out UNRESOLVED_float);
procedure OREAD (L : inout LINE; VALUE : out UNRESOLVED_float;
GOOD : out BOOLEAN);
alias OCTAL_READ is OREAD [LINE, UNRESOLVED_FLOAT, BOOLEAN];
alias OCTAL_READ is OREAD [LINE, UNRESOLVED_FLOAT];
alias OCTAL_WRITE is OWRITE [LINE, UNRESOLVED_FLOAT, SIDE, WIDTH];
-- Hex write with padding, no separators
procedure HWRITE (
L : inout LINE; -- access type (pointer)
VALUE : in UNRESOLVED_float; -- value to write
JUSTIFIED : in SIDE := right; -- which side to justify text
FIELD : in WIDTH := 0); -- width of field
-- Hex read with padding, no separators used
procedure HREAD (L : inout LINE; VALUE : out UNRESOLVED_float);
procedure HREAD (L : inout LINE; VALUE : out UNRESOLVED_float;
GOOD : out BOOLEAN);
alias HEX_READ is HREAD [LINE, UNRESOLVED_FLOAT, BOOLEAN];
alias HEX_READ is HREAD [LINE, UNRESOLVED_FLOAT];
alias HEX_WRITE is HWRITE [LINE, UNRESOLVED_FLOAT, SIDE, WIDTH];
-- returns "S:EEEE:FFFFFFFF"
function to_string (value : UNRESOLVED_float) return STRING;
alias TO_BSTRING is TO_STRING [UNRESOLVED_FLOAT return STRING];
alias TO_BINARY_STRING is TO_STRING [UNRESOLVED_FLOAT return STRING];
-- Returns a HEX string, with padding
function to_hstring (value : UNRESOLVED_float) return STRING;
alias TO_HEX_STRING is TO_HSTRING [UNRESOLVED_FLOAT return STRING];
-- Returns and octal string, with padding
function to_ostring (value : UNRESOLVED_float) return STRING;
alias TO_OCTAL_STRING is TO_OSTRING [UNRESOLVED_FLOAT return STRING];
function from_string (
bstring : STRING; -- binary string
constant exponent_width : NATURAL := float_exponent_width;
constant fraction_width : NATURAL := float_fraction_width)
return UNRESOLVED_float;
alias from_bstring is from_string [STRING, NATURAL, NATURAL
return UNRESOLVED_float];
alias from_binary_string is from_string [STRING, NATURAL, NATURAL
return UNRESOLVED_float];
function from_ostring (
ostring : STRING; -- Octal string
constant exponent_width : NATURAL := float_exponent_width;
constant fraction_width : NATURAL := float_fraction_width)
return UNRESOLVED_float;
alias from_octal_string is from_ostring [STRING, NATURAL, NATURAL
return UNRESOLVED_float];
function from_hstring (
hstring : STRING; -- hex string
constant exponent_width : NATURAL := float_exponent_width;
constant fraction_width : NATURAL := float_fraction_width)
return UNRESOLVED_float;
alias from_hex_string is from_hstring [STRING, NATURAL, NATURAL
return UNRESOLVED_float];
function from_string (
bstring : STRING; -- binary string
size_res : UNRESOLVED_float) -- used for sizing only
return UNRESOLVED_float;
alias from_bstring is from_string [STRING, UNRESOLVED_float
return UNRESOLVED_float];
alias from_binary_string is from_string [STRING, UNRESOLVED_float
return UNRESOLVED_float];
function from_ostring (
ostring : STRING; -- Octal string
size_res : UNRESOLVED_float) -- used for sizing only
return UNRESOLVED_float;
alias from_octal_string is from_ostring [STRING, UNRESOLVED_float
return UNRESOLVED_float];
function from_hstring (
hstring : STRING; -- hex string
size_res : UNRESOLVED_float) -- used for sizing only
return UNRESOLVED_float;
alias from_hex_string is from_hstring [STRING, UNRESOLVED_float
return UNRESOLVED_float];
-- rtl_synthesis on
-- pragma synthesis_on
-- IN VHDL-2006 std_logic_vector is a subtype of std_ulogic_vector, so these
-- extra functions are needed for compatability.
function to_float (
arg : STD_LOGIC_VECTOR;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width) -- length of FP output fraction
return UNRESOLVED_float;
function to_float (
arg : STD_LOGIC_VECTOR;
size_res : UNRESOLVED_float)
return UNRESOLVED_float;
end package float_pkg;
-------------------------------------------------------------------------------
-- Proposed package body for the VHDL-200x-FT float_pkg package
-- This version is optimized for Synthesis, and not for simulation.
-- Note that there are functional differences between the synthesis and
-- simulation packages bodies. The Synthesis version is preferred.
-- This package body supplies a recommended implementation of these functions
-- Version : $Revision: 1.9 $
-- Date : $Date: 2007-04-04 13:59:52-04 $
--
-- Created for VHDL-200X par, David Bishop (dbishop@vhdl.org)
-------------------------------------------------------------------------------
package body float_pkg is
-- Author David Bishop (dbishop@vhdl.org)
-----------------------------------------------------------------------------
-- type declarations
-----------------------------------------------------------------------------
-- This deferred constant will tell you if the package body is synthesizable
-- or implemented as real numbers, set to "true" if synthesizable.
constant fphdlsynth_or_real : BOOLEAN := true; -- deferred constant
-- types of boundary conditions
type boundary_type is (normal, infinity, zero, denormal);
-- null range array constant
constant NAFP : UNRESOLVED_float (0 downto 1) := (others => '0');
constant NSLV : STD_ULOGIC_VECTOR (0 downto 1) := (others => '0');
-- %%% Replicated functions
-- These funcitons are replicated so that we don't need to reference the new
-- 2006 package std.standard, std_logic_1164 and numeric_std.
function maximum (
l, r : integer) -- inputs
return integer is
begin -- function max
if l > r then return l;
else return r;
end if;
end function maximum;
function minimum (
l, r : integer) -- inputs
return integer is
begin -- function min
if l > r then return r;
else return l;
end if;
end function minimum;
function or_reduce (arg : STD_ULOGIC_VECTOR)
return STD_LOGIC is
variable Upper, Lower : STD_ULOGIC;
variable Half : INTEGER;
variable BUS_int : STD_ULOGIC_VECTOR (arg'length - 1 downto 0);
variable Result : STD_ULOGIC;
begin
if (arg'length < 1) then -- In the case of a NULL range
Result := '0';
else
BUS_int := to_ux01 (arg);
if (BUS_int'length = 1) then
Result := BUS_int (BUS_int'left);
elsif (BUS_int'length = 2) then
Result := BUS_int (BUS_int'right) or BUS_int (BUS_int'left);
else
Half := (BUS_int'length + 1) / 2 + BUS_int'right;
Upper := or_reduce (BUS_int (BUS_int'left downto Half));
Lower := or_reduce (BUS_int (Half - 1 downto BUS_int'right));
Result := Upper or Lower;
end if;
end if;
return Result;
end function or_reduce;
function or_reduce (arg : UNSIGNED)
return STD_ULOGIC is
begin
return or_reduce (std_ulogic_vector (arg));
end function or_reduce;
function or_reduce (arg : SIGNED)
return STD_ULOGIC is
begin
return or_reduce (std_ulogic_vector (arg));
end function or_reduce;
function or_reduce (arg : std_logic_vector)
return STD_ULOGIC is
begin
return or_reduce (std_ulogic_vector (arg));
end function or_reduce;
-- purpose: AND all of the bits in a vector together
-- This is a copy of the proposed "and_reduce" from 1076.3
function and_reduce (arg : STD_ULOGIC_VECTOR)
return STD_LOGIC is
variable Upper, Lower : STD_ULOGIC;
variable Half : INTEGER;
variable BUS_int : STD_ULOGIC_VECTOR (arg'length - 1 downto 0);
variable Result : STD_ULOGIC;
begin
if (arg'length < 1) then -- In the case of a NULL range
Result := '1';
else
BUS_int := to_ux01 (arg);
if (BUS_int'length = 1) then
Result := BUS_int (BUS_int'left);
elsif (BUS_int'length = 2) then
Result := BUS_int (BUS_int'right) and BUS_int (BUS_int'left);
else
Half := (BUS_int'length + 1) / 2 + BUS_int'right;
Upper := and_reduce (BUS_int (BUS_int'left downto Half));
Lower := and_reduce (BUS_int (Half - 1 downto BUS_int'right));
Result := Upper and Lower;
end if;
end if;
return Result;
end function and_reduce;
function and_reduce (arg : UNSIGNED)
return STD_ULOGIC is
begin
return and_reduce (std_ulogic_vector (arg));
end function and_reduce;
function and_reduce (arg : SIGNED)
return STD_ULOGIC is
begin
return and_reduce (std_ulogic_vector (arg));
end function and_reduce;
function xor_reduce (arg : STD_ULOGIC_VECTOR) return STD_ULOGIC is
variable Upper, Lower : STD_ULOGIC;
variable Half : INTEGER;
variable BUS_int : STD_ULOGIC_VECTOR (arg'length - 1 downto 0);
variable Result : STD_ULOGIC := '0'; -- In the case of a NULL range
begin
if (arg'length >= 1) then
BUS_int := to_ux01 (arg);
if (BUS_int'length = 1) then
Result := BUS_int (BUS_int'left);
elsif (BUS_int'length = 2) then
Result := BUS_int(BUS_int'right) xor BUS_int(BUS_int'left);
else
Half := (BUS_int'length + 1) / 2 + BUS_int'right;
Upper := xor_reduce (BUS_int (BUS_int'left downto Half));
Lower := xor_reduce (BUS_int (Half - 1 downto BUS_int'right));
Result := Upper xor Lower;
end if;
end if;
return Result;
end function xor_reduce;
function nand_reduce(arg : std_ulogic_vector) return STD_ULOGIC is
begin
return not and_reduce (arg);
end function nand_reduce;
function nor_reduce(arg : std_ulogic_vector) return STD_ULOGIC is
begin
return not or_reduce (arg);
end function nor_reduce;
function xnor_reduce(arg : std_ulogic_vector) return STD_ULOGIC is
begin
return not xor_reduce (arg);
end function xnor_reduce;
function find_leftmost (ARG : UNSIGNED; Y : STD_ULOGIC)
return INTEGER is
begin
for INDEX in ARG'range loop
if ARG(INDEX) = Y then
return INDEX;
end if;
end loop;
return -1;
end function find_leftmost;
-- Match table, copied form new std_logic_1164
type stdlogic_table is array(STD_ULOGIC, STD_ULOGIC) of STD_ULOGIC;
constant match_logic_table : stdlogic_table := (
-----------------------------------------------------
-- U X 0 1 Z W L H - | |
-----------------------------------------------------
('U', 'U', 'U', 'U', 'U', 'U', 'U', 'U', '1'), -- | U |
('U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', '1'), -- | X |
('U', 'X', '1', '0', 'X', 'X', '1', '0', '1'), -- | 0 |
('U', 'X', '0', '1', 'X', 'X', '0', '1', '1'), -- | 1 |
('U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', '1'), -- | Z |
('U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', '1'), -- | W |
('U', 'X', '1', '0', 'X', 'X', '1', '0', '1'), -- | L |
('U', 'X', '0', '1', 'X', 'X', '0', '1', '1'), -- | H |
('1', '1', '1', '1', '1', '1', '1', '1', '1') -- | - |
);
constant no_match_logic_table : stdlogic_table := (
-----------------------------------------------------
-- U X 0 1 Z W L H - | |
-----------------------------------------------------
('U', 'U', 'U', 'U', 'U', 'U', 'U', 'U', '0'), -- | U |
('U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', '0'), -- | X |
('U', 'X', '0', '1', 'X', 'X', '0', '1', '0'), -- | 0 |
('U', 'X', '1', '0', 'X', 'X', '1', '0', '0'), -- | 1 |
('U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', '0'), -- | Z |
('U', 'X', 'X', 'X', 'X', 'X', 'X', 'X', '0'), -- | W |
('U', 'X', '0', '1', 'X', 'X', '0', '1', '0'), -- | L |
('U', 'X', '1', '0', 'X', 'X', '1', '0', '0'), -- | H |
('0', '0', '0', '0', '0', '0', '0', '0', '0') -- | - |
);
-------------------------------------------------------------------
-- ?= functions, Similar to "std_match", but returns "std_ulogic".
-------------------------------------------------------------------
-- %%% FUNCTION "?=" ( l, r : std_ulogic ) RETURN std_ulogic IS
function \?=\ (l, r : STD_ULOGIC) return STD_ULOGIC is
begin
return match_logic_table (l, r);
end function \?=\;
-- %%% END FUNCTION "?=";
-- %%% FUNCTION "?/=" ( l, r : std_ulogic ) RETURN std_ulogic is
function \?/=\ (l, r : STD_ULOGIC) return STD_ULOGIC is
begin
return no_match_logic_table (l, r);
end function \?/=\;
-- %%% END FUNCTION "?/=";
function \?=\ (l, r : STD_ULOGIC_VECTOR) return STD_ULOGIC is
begin
return \?=\ (ufixed(l), ufixed(r));
end function \?=\;
function Is_X ( s : UNSIGNED ) return BOOLEAN is
begin
return Is_X (STD_LOGIC_VECTOR (s));
end function Is_X;
function Is_X ( s : SIGNED ) return BOOLEAN is
begin
return Is_X (STD_LOGIC_VECTOR (s));
end function Is_X;
-- %%% END replicated functions
-- Special version of "minimum" to do some boundary checking
function mine (L, R : INTEGER)
return INTEGER is
begin -- function minimum
if (L = INTEGER'low or R = INTEGER'low) then
report float_pkg'instance_name
& " Unbounded number passed, was a literal used?"
severity error;
return 0;
end if;
return minimum (L, R);
end function mine;
-- Generates the base number for the exponent normalization offset.
function gen_expon_base (
constant exponent_width : NATURAL)
return SIGNED is
variable result : SIGNED (exponent_width-1 downto 0);
begin
result := (others => '1');
result (exponent_width-1) := '0';
return result;
end function gen_expon_base;
-- Integer version of the "log2" command (contributed by Peter Ashenden)
function log2 (A : NATURAL) return NATURAL is
variable quotient : NATURAL;
variable result : NATURAL := 0;
begin
quotient := A / 2;
while quotient > 0 loop
quotient := quotient / 2;
result := result + 1;
end loop;
return result;
end function log2;
-- Function similar to the ILOGB function in MATH_REAL
function log2 (A : REAL) return INTEGER is
variable Y : REAL;
variable N : INTEGER := 0;
begin
if (A = 1.0 or A = 0.0) then
return 0;
end if;
Y := A;
if(A > 1.0) then
while Y >= 2.0 loop
Y := Y / 2.0;
N := N + 1;
end loop;
return N;
end if;
-- O < Y < 1
while Y < 1.0 loop
Y := Y * 2.0;
N := N - 1;
end loop;
return N;
end function log2;
-- purpose: Test the boundary conditions of a Real number
procedure test_boundary (
arg : in REAL; -- Input, converted to real
constant fraction_width : in NATURAL; -- length of FP output fraction
constant exponent_width : in NATURAL; -- length of FP exponent
constant denormalize : in BOOLEAN := true; -- Use IEEE extended FP
variable btype : out boundary_type;
variable log2i : out INTEGER
) is
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
constant exp_min : SIGNED (12 downto 0) :=
-(resize(expon_base, 13)) + 1; -- Minimum normal exponent
constant exp_ext_min : SIGNED (12 downto 0) :=
exp_min - fraction_width; -- Minimum for denormal exponent
variable log2arg : INTEGER; -- log2 of argument
begin -- function test_boundary
-- Check to see if the exponent is big enough
-- Note that the argument is always an absolute value at this point.
log2arg := log2(arg);
if arg = 0.0 then
btype := zero;
elsif exponent_width > 11 then -- Exponent for Real is 11 (64 bit)
btype := normal;
else
if log2arg < to_integer(exp_min) then
if denormalize then
if log2arg < to_integer(exp_ext_min) then
btype := zero;
else
btype := denormal;
end if;
else
if log2arg < to_integer(exp_min)-1 then
btype := zero;
else
btype := normal; -- Can still represent this number
end if;
end if;
elsif exponent_width < 11 then
if log2arg > to_integer(expon_base)+1 then
btype := infinity;
else
btype := normal;
end if;
else
btype := normal;
end if;
end if;
log2i := log2arg;
end procedure test_boundary;
-- purpose: Rounds depending on the state of the "round_style"
-- Logic taken from
-- "What Every Computer Scientist Should Know About Floating Point Arithmetic"
-- by David Goldberg (1991)
function check_round (
fract_in : STD_ULOGIC; -- input fraction
sign : STD_ULOGIC; -- sign bit
remainder : UNSIGNED; -- remainder to round from
sticky : STD_ULOGIC := '0'; -- Sticky bit
constant round_style : round_type) -- rounding type
return BOOLEAN is
variable result : BOOLEAN;
variable or_reduced : STD_ULOGIC;
begin -- function check_round
result := false;
if (remainder'length > 0) then -- if remainder in a null array
or_reduced := or_reduce (remainder & sticky);
rounding_case : case round_style is
when round_nearest => -- Round Nearest, default mode
if remainder(remainder'high) = '1' then -- round
if (remainder'length > 1) then
if ((or_reduce (remainder(remainder'high-1
downto remainder'low)) = '1'
or sticky = '1')
or fract_in = '1') then
-- Make the bottom bit zero if possible if we are at 1/2
result := true;
end if;
else
result := (fract_in = '1' or sticky = '1');
end if;
end if;
when round_inf => -- round up if positive, else truncate.
if or_reduced = '1' and sign = '0' then
result := true;
end if;
when round_neginf => -- round down if negative, else truncate.
if or_reduced = '1' and sign = '1' then
result := true;
end if;
when round_zero => -- round toward 0 Truncate
null;
end case rounding_case;
end if;
return result;
end function check_round;
-- purpose: Rounds depending on the state of the "round_style"
-- unsigned version
procedure fp_round (
fract_in : in UNSIGNED; -- input fraction
expon_in : in SIGNED; -- input exponent
fract_out : out UNSIGNED; -- output fraction
expon_out : out SIGNED) is -- output exponent
begin -- procedure fp_round
if and_reduce (fract_in) = '1' then -- Fraction is all "1"
expon_out := expon_in + 1;
fract_out := to_unsigned(0, fract_out'high+1);
else
expon_out := expon_in;
fract_out := fract_in + 1;
end if;
end procedure fp_round;
-- This version of break_number doesn't call "classfp"
procedure break_number ( -- internal version
arg : in UNRESOLVED_float;
fptyp : in valid_fpstate;
denormalize : in BOOLEAN := true;
fract : out UNSIGNED;
expon : out SIGNED) is
constant fraction_width : NATURAL := -arg'low; -- length of FP output fraction
constant exponent_width : NATURAL := arg'high; -- length of FP output exponent
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable exp : SIGNED (expon'range);
begin
fract (fraction_width-1 downto 0) :=
UNSIGNED (to_slv(arg(-1 downto -fraction_width)));
breakcase : case fptyp is
when pos_zero | neg_zero =>
fract (fraction_width) := '0';
exp := -expon_base;
when pos_denormal | neg_denormal =>
if denormalize then
exp := -expon_base;
fract (fraction_width) := '0';
else
exp := -expon_base - 1;
fract (fraction_width) := '1';
end if;
when pos_normal | neg_normal | pos_inf | neg_inf =>
fract (fraction_width) := '1';
exp := SIGNED(arg(exponent_width-1 downto 0));
exp (exponent_width-1) := not exp(exponent_width-1);
when others =>
assert NO_WARNING
report float_pkg'instance_name
& "BREAK_NUMBER: " &
"Meta state detected in fp_break_number process"
severity warning;
-- complete the case, if a NAN goes in, a NAN comes out.
exp := (others => '1');
fract (fraction_width) := '1';
end case breakcase;
expon := exp;
end procedure break_number;
-- purpose: floating point to UNSIGNED
-- Used by to_integer, to_unsigned, and to_signed functions
procedure float_to_unsigned (
arg : in UNRESOLVED_float; -- floating point input
variable sign : out STD_ULOGIC; -- sign of output
variable frac : out UNSIGNED; -- unsigned biased output
constant denormalize : in BOOLEAN; -- turn on denormalization
constant bias : in NATURAL; -- bias for fixed point
constant round_style : in round_type) is -- rounding method
constant fraction_width : INTEGER := -mine(arg'low, arg'low); -- length of FP output fraction
constant exponent_width : INTEGER := arg'high; -- length of FP output exponent
variable fract : UNSIGNED (frac'range); -- internal version of frac
variable isign : STD_ULOGIC; -- internal version of sign
variable exp : INTEGER; -- Exponent
variable expon : SIGNED (exponent_width-1 downto 0); -- Vectorized exp
-- Base to divide fraction by
variable frac_shift : UNSIGNED (frac'high+3 downto 0); -- Fraction shifted
variable shift : INTEGER;
variable remainder : UNSIGNED (2 downto 0);
variable round : STD_ULOGIC; -- round BIT
begin
isign := to_x01(arg(arg'high));
-- exponent /= '0', normal floating point
expon := to_01(SIGNED(arg (exponent_width-1 downto 0)), 'X');
expon(exponent_width-1) := not expon(exponent_width-1);
exp := to_integer (expon);
-- Figure out the fraction
fract := (others => '0'); -- fill with zero
fract (fract'high) := '1'; -- Add the "1.0".
shift := (fract'high-1) - exp;
if fraction_width > fract'high then -- Can only use size-2 bits
fract (fract'high-1 downto 0) := UNSIGNED (to_slv (arg(-1 downto
-fract'high)));
else -- can use all bits
fract (fract'high-1 downto fract'high-fraction_width) :=
UNSIGNED (to_slv (arg(-1 downto -fraction_width)));
end if;
frac_shift := fract & "000";
if shift < 0 then -- Overflow
fract := (others => '1');
else
frac_shift := shift_right (frac_shift, shift);
fract := frac_shift (frac_shift'high downto 3);
remainder := frac_shift (2 downto 0);
-- round (round_zero will bypass this and truncate)
case round_style is
when round_nearest =>
round := remainder(2) and
(fract (0) or (or_reduce (remainder (1 downto 0))));
when round_inf =>
round := remainder(2) and not isign;
when round_neginf =>
round := remainder(2) and isign;
when others =>
round := '0';
end case;
if round = '1' then
fract := fract + 1;
end if;
end if;
frac := fract;
sign := isign;
end procedure float_to_unsigned;
-- purpose: returns a part of a vector, this function is here because
-- or (fractr (to_integer(shiftx) downto 0));
-- can't be synthesized in some synthesis tools.
function smallfract (
arg : UNSIGNED;
shift : NATURAL)
return STD_ULOGIC is
variable orx : STD_ULOGIC;
begin
orx := arg(shift);
for i in arg'range loop
if i < shift then
orx := arg(i) or orx;
end if;
end loop;
return orx;
end function smallfract;
---------------------------------------------------------------------------
-- Visible functions
---------------------------------------------------------------------------
-- purpose: converts the negative index to a positive one
-- negative indices are illegal in 1164 and 1076.3
function to_suv (
arg : UNRESOLVED_float) -- fp vector
return STD_ULOGIC_VECTOR is
variable result : STD_ULOGIC_VECTOR (arg'length-1 downto 0);
begin -- function to_std_ulogic_vector
if arg'length < 1 then
return NSLV;
end if;
result := STD_ULOGIC_VECTOR (arg);
return result;
end function to_suv;
-- Converts an fp into an SULV
function to_slv (arg : UNRESOLVED_float) return STD_LOGIC_VECTOR is
begin
return to_stdlogicvector (to_suv (arg));
end function to_slv;
-- purpose: normalizes a floating point number
-- This version assumes an "unsigned" input with
function normalize (
fract : UNSIGNED; -- fraction, unnormalized
expon : SIGNED; -- exponent, normalized by -1
sign : STD_ULOGIC; -- sign BIT
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
constant exponent_width : NATURAL := float_exponent_width; -- size of output exponent
constant fraction_width : NATURAL := float_fraction_width; -- size of output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float is
variable sfract : UNSIGNED (fract'high downto 0); -- shifted fraction
variable rfract : UNSIGNED (fraction_width-1 downto 0); -- fraction
variable exp : SIGNED (exponent_width+1 downto 0); -- exponent
variable rexp : SIGNED (exponent_width+1 downto 0); -- result exponent
variable rexpon : UNSIGNED (exponent_width-1 downto 0); -- exponent
variable result : UNRESOLVED_float (exponent_width downto -fraction_width); -- result
variable shiftr : INTEGER; -- shift amount
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable round : BOOLEAN;
begin -- function normalize
result (exponent_width) := sign; -- sign bit
round := false;
shiftr := find_leftmost (to_01(fract), '1') -- Find the first "1"
- fraction_width - nguard; -- subtract the length we want
exp := resize (expon, exp'length) + shiftr;
if (or_reduce (fract) = '0') then -- Zero
result := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif ((exp <= -resize(expon_base, exp'length)-1) and denormalize)
or ((exp < -resize(expon_base, exp'length)-1) and not denormalize) then
if (exp >= -resize(expon_base, exp'length)-fraction_width-1)
and denormalize then
exp := -resize(expon_base, exp'length);
shiftr := to_integer (expon + expon_base); -- new shift
sfract := fract sll shiftr; -- shift
if nguard > 0 then
round := check_round (
fract_in => sfract (nguard),
sign => sign,
remainder => sfract(nguard-1 downto 0),
round_style => round_style);
end if;
if round then
fp_round(fract_in => sfract (fraction_width-1+nguard downto nguard),
expon_in => exp,
fract_out => rfract,
expon_out => rexp);
else
rfract := sfract (fraction_width-1+nguard downto nguard);
rexp := exp;
end if;
rexpon := UNSIGNED ((rexp(exponent_width-1 downto 0))-1);
rexpon(exponent_width-1) := not rexpon(exponent_width-1);
result (rexpon'range) := UNRESOLVED_float(rexpon);
result (-1 downto -fraction_width) := UNRESOLVED_float(rfract);
else -- return zero
result := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
elsif (exp > expon_base-1) then -- infinity
result := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
result (exponent_width) := sign; -- redo sign bit for neg inf.
else -- normal number
sfract := fract srl shiftr; -- shift
if nguard > 0 then
round := check_round (
fract_in => sfract (nguard),
sign => sign,
remainder => sfract(nguard-1 downto 0),
sticky => sticky,
round_style => round_style);
end if;
if round then
fp_round(fract_in => sfract (fraction_width-1+nguard downto nguard),
expon_in => exp(rexp'range),
fract_out => rfract,
expon_out => rexp);
else
rfract := sfract (fraction_width-1+nguard downto nguard);
rexp := exp(rexp'range);
end if;
-- result
rexpon := UNSIGNED (rexp(exponent_width-1 downto 0));
rexpon(exponent_width-1) := not rexpon(exponent_width-1);
result (rexpon'range) := UNRESOLVED_float(rexpon);
result (-1 downto -fraction_width) := UNRESOLVED_float(rfract);
end if;
return result;
end function normalize;
-- purpose: normalizes a floating point number
-- This version assumes a "ufixed" input
function normalize (
fract : ufixed; -- unsigned fixed point
expon : SIGNED; -- exponent, normalized by -1
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
constant exponent_width : NATURAL := float_exponent_width; -- size of output exponent
constant fraction_width : NATURAL := float_fraction_width; -- size of output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable arguns : UNSIGNED (fract'high + fraction_width + nguard
downto 0) := (others => '0');
begin -- function normalize
arguns (arguns'high downto maximum (arguns'high-fract'length+1, 0)) :=
UNSIGNED (to_slv (fract));
result := normalize (fract => arguns,
expon => expon,
sign => sign,
sticky => sticky,
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => nguard);
return result;
end function normalize;
-- purpose: normalizes a floating point number
-- This version assumes a "ufixed" input with a "size_res" input
function normalize (
fract : ufixed; -- unsigned fixed point
expon : SIGNED; -- exponent, normalized by -1
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
size_res : UNRESOLVED_float; -- used for sizing only
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float is
constant fraction_width : NATURAL := -size_res'low;
constant exponent_width : NATURAL := size_res'high;
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable arguns : UNSIGNED (fract'high + fraction_width + nguard
downto 0) := (others => '0');
begin -- function normalize
arguns (arguns'high downto maximum (arguns'high-fract'length+1, 0)) :=
UNSIGNED (to_slv (fract));
result := normalize (fract => arguns,
expon => expon,
sign => sign,
sticky => sticky,
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => nguard);
return result;
end function normalize;
-- Regular "normalize" function with a "size_res" input.
function normalize (
fract : UNSIGNED; -- unsigned
expon : SIGNED; -- exponent - 1, normalized
sign : STD_ULOGIC; -- sign bit
sticky : STD_ULOGIC := '0'; -- Sticky bit (rounding)
size_res : UNRESOLVED_float; -- used for sizing only
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant nguard : NATURAL := float_guard_bits) -- guard bits
return UNRESOLVED_float is
begin
return normalize (fract => fract,
expon => expon,
sign => sign,
sticky => sticky,
fraction_width => -size_res'low,
exponent_width => size_res'high,
round_style => round_style,
denormalize => denormalize,
nguard => nguard);
end function normalize;
-- Returns the class which X falls into
function Classfp (
x : UNRESOLVED_float; -- floating point input
check_error : BOOLEAN := float_check_error) -- check for errors
return valid_fpstate is
constant fraction_width : INTEGER := -mine(x'low, x'low); -- length of FP output fraction
constant exponent_width : INTEGER := x'high; -- length of FP output exponent
variable arg : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- classfp
if (arg'length < 1 or fraction_width < 3 or exponent_width < 3
or x'left < x'right) then
report float_pkg'instance_name
& "CLASSFP: " &
"Floating point number detected with a bad range"
severity error;
return isx;
end if;
-- Check for "X".
arg := to_01 (x, 'X');
if (arg(0) = 'X') then
return isx; -- If there is an X in the number
-- Special cases, check for illegal number
elsif check_error and
(and_reduce (STD_ULOGIC_VECTOR (arg (exponent_width-1 downto 0)))
= '1') then -- Exponent is all "1".
if or_reduce (to_slv (arg (-1 downto -fraction_width)))
/= '0' then -- Fraction must be all "0" or this is not a number.
if (arg(-1) = '1') then -- From "W. Khan - IEEE standard
return nan; -- 754 binary FP Signaling nan (Not a number)
else
return quiet_nan;
end if;
-- Check for infinity
elsif arg(exponent_width) = '0' then
return pos_inf; -- Positive infinity
else
return neg_inf; -- Negative infinity
end if;
-- check for "0"
elsif or_reduce (STD_LOGIC_VECTOR (arg (exponent_width-1 downto 0)))
= '0' then -- Exponent is all "0"
if or_reduce (to_slv (arg (-1 downto -fraction_width)))
= '0' then -- Fraction is all "0"
if arg(exponent_width) = '0' then
return pos_zero; -- Zero
else
return neg_zero;
end if;
else
if arg(exponent_width) = '0' then
return pos_denormal; -- Denormal number (ieee extended fp)
else
return neg_denormal;
end if;
end if;
else
if arg(exponent_width) = '0' then
return pos_normal; -- Normal FP number
else
return neg_normal;
end if;
end if;
end function Classfp;
procedure break_number (
arg : in UNRESOLVED_float;
denormalize : in BOOLEAN := float_denormalize;
check_error : in BOOLEAN := float_check_error;
fract : out UNSIGNED;
expon : out SIGNED;
sign : out STD_ULOGIC) is
constant fraction_width : NATURAL := -mine(arg'low, arg'low); -- length of FP output fraction
variable fptyp : valid_fpstate;
begin
fptyp := Classfp (arg, check_error);
sign := to_x01(arg(arg'high));
break_number (
arg => arg,
fptyp => fptyp,
denormalize => denormalize,
fract => fract,
expon => expon);
end procedure break_number;
procedure break_number (
arg : in UNRESOLVED_float;
denormalize : in BOOLEAN := float_denormalize;
check_error : in BOOLEAN := float_check_error;
fract : out ufixed; -- 1 downto -fraction_width
expon : out SIGNED; -- exponent_width-1 downto 0
sign : out STD_ULOGIC) is
constant fraction_width : NATURAL := -mine(arg'low, arg'low); -- length of FP output fraction
variable fptyp : valid_fpstate;
variable ufract : UNSIGNED (fraction_width downto 0); -- unsigned fraction
begin
fptyp := Classfp (arg, check_error);
sign := to_x01(arg(arg'high));
break_number (
arg => arg,
fptyp => fptyp,
denormalize => denormalize,
fract => ufract,
expon => expon);
fract (0 downto -fraction_width) := ufixed (ufract);
end procedure break_number;
-- Arithmetic functions
function "abs" (
arg : UNRESOLVED_float) -- floating point input
return UNRESOLVED_float is
variable result : UNRESOLVED_float (arg'range); -- result
begin
if (arg'length > 0) then
result := to_01 (arg, 'X');
result (arg'high) := '0'; -- set the sign bit to positive
return result;
else
return NAFP;
end if;
end function "abs";
-- IEEE 754 "negative" function
function "-" (
arg : UNRESOLVED_float) -- floating point input
return UNRESOLVED_float is
variable result : UNRESOLVED_float (arg'range); -- result
begin
if (arg'length > 0) then
result := to_01 (arg, 'X');
result (arg'high) := not result (arg'high); -- invert sign bit
return result;
else
return NAFP;
end if;
end function "-";
-- Addition, adds two floating point numbers
function add (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
constant addguard : NATURAL := guard; -- add one guard bit
variable lfptype, rfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable fractl, fractr : UNSIGNED (fraction_width+1+addguard downto 0); -- fractions
variable fractc, fracts : UNSIGNED (fractl'range); -- constant and shifted variables
variable urfract, ulfract : UNSIGNED (fraction_width downto 0);
variable ufract : UNSIGNED (fraction_width+1+addguard downto 0);
variable exponl, exponr : SIGNED (exponent_width-1 downto 0); -- exponents
variable rexpon : SIGNED (exponent_width downto 0); -- result exponent
variable shiftx : SIGNED (exponent_width downto 0); -- shift fractions
variable sign : STD_ULOGIC; -- sign of the output
variable leftright : BOOLEAN; -- left or right used
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
variable sticky : STD_ULOGIC; -- Holds precision for rounding
begin -- addition
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
if (lfptype = isx or rfptype = isx) then
fpresult := (others => 'X');
elsif (lfptype = nan or lfptype = quiet_nan or
rfptype = nan or rfptype = quiet_nan)
-- Return quiet NAN, IEEE754-1985-7.1,1
or (lfptype = pos_inf and rfptype = neg_inf)
or (lfptype = neg_inf and rfptype = pos_inf) then
-- Return quiet NAN, IEEE754-1985-7.1,2
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (lfptype = pos_inf or rfptype = pos_inf) then -- x + inf = inf
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (lfptype = neg_inf or rfptype = neg_inf) then -- x - inf = -inf
fpresult := neg_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
lfptype := classfp (lresize, false); -- errors already checked
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rfptype := classfp (rresize, false); -- errors already checked
break_number (
arg => lresize,
fptyp => lfptype,
denormalize => denormalize,
fract => ulfract,
expon => exponl);
fractl := (others => '0');
fractl (fraction_width+addguard downto addguard) := ulfract;
break_number (
arg => rresize,
fptyp => rfptype,
denormalize => denormalize,
fract => urfract,
expon => exponr);
fractr := (others => '0');
fractr (fraction_width+addguard downto addguard) := urfract;
shiftx := (exponl(exponent_width-1) & exponl) - exponr;
if shiftx < -fractl'high then
rexpon := exponr(exponent_width-1) & exponr;
fractc := fractr;
fracts := (others => '0'); -- add zero
leftright := false;
sticky := or_reduce (fractl);
elsif shiftx < 0 then
shiftx := - shiftx;
fracts := shift_right (fractl, to_integer(shiftx));
fractc := fractr;
rexpon := exponr(exponent_width-1) & exponr;
leftright := false;
-- sticky := or_reduce (fractl (to_integer(shiftx) downto 0));
sticky := smallfract (fractl, to_integer(shiftx));
elsif shiftx = 0 then
rexpon := exponl(exponent_width-1) & exponl;
sticky := '0';
if fractr > fractl then
fractc := fractr;
fracts := fractl;
leftright := false;
else
fractc := fractl;
fracts := fractr;
leftright := true;
end if;
elsif shiftx > fractr'high then
rexpon := exponl(exponent_width-1) & exponl;
fracts := (others => '0'); -- add zero
fractc := fractl;
leftright := true;
sticky := or_reduce (fractr);
elsif shiftx > 0 then
fracts := shift_right (fractr, to_integer(shiftx));
fractc := fractl;
rexpon := exponl(exponent_width-1) & exponl;
leftright := true;
-- sticky := or_reduce (fractr (to_integer(shiftx) downto 0));
sticky := smallfract (fractr, to_integer(shiftx));
end if;
-- add
fracts (0) := fracts (0) or sticky; -- Or the sticky bit into the LSB
if l(l'high) = r(r'high) then
ufract := fractc + fracts;
sign := l(l'high);
else -- signs are different
ufract := fractc - fracts; -- always positive result
if leftright then -- Figure out which sign to use
sign := l(l'high);
else
sign := r(r'high);
end if;
end if;
-- normalize
fpresult := normalize (fract => ufract,
expon => rexpon,
sign => sign,
sticky => sticky,
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => addguard);
end if;
return fpresult;
end function add;
-- Subtraction, Calls "add".
function subtract (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
variable negr : UNRESOLVED_float (r'range); -- negative version of r
begin
negr := -r; -- r := -r
return add (l => l,
r => negr,
round_style => round_style,
guard => guard,
check_error => check_error,
denormalize => denormalize);
end function subtract;
-- Floating point multiply
function multiply (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
constant multguard : NATURAL := guard; -- guard bits
variable lfptype, rfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable fractl, fractr : UNSIGNED (fraction_width downto 0); -- fractions
variable rfract : UNSIGNED ((2*(fraction_width))+1 downto 0); -- result fraction
variable sfract : UNSIGNED (fraction_width+1+multguard downto 0); -- result fraction
variable exponl, exponr : SIGNED (exponent_width-1 downto 0); -- exponents
variable rexpon : SIGNED (exponent_width downto 0); -- result exponent
variable fp_sign : STD_ULOGIC; -- sign of result
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
variable sticky : STD_ULOGIC; -- Holds precision for rounding
begin -- multiply
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
if (lfptype = isx or rfptype = isx) then
fpresult := (others => 'X');
elsif ((lfptype = nan or lfptype = quiet_nan or
rfptype = nan or rfptype = quiet_nan)) then
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (((lfptype = pos_inf or lfptype = neg_inf) and
(rfptype = pos_zero or rfptype = neg_zero)) or
((rfptype = pos_inf or rfptype = neg_inf) and
(lfptype = pos_zero or lfptype = neg_zero))) then -- 0 * inf
-- Return quiet NAN, IEEE754-1985-7.1,3
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (lfptype = pos_inf or rfptype = pos_inf
or lfptype = neg_inf or rfptype = neg_inf) then -- x * inf = inf
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
-- figure out the sign
fpresult (exponent_width) := l(l'high) xor r(r'high);
else
fp_sign := l(l'high) xor r(r'high); -- figure out the sign
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
lfptype := classfp (lresize, false); -- errors already checked
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rfptype := classfp (rresize, false); -- errors already checked
break_number (
arg => lresize,
fptyp => lfptype,
denormalize => denormalize,
fract => fractl,
expon => exponl);
break_number (
arg => rresize,
fptyp => rfptype,
denormalize => denormalize,
fract => fractr,
expon => exponr);
-- multiply
rfract := fractl * fractr; -- Multiply the fraction
sfract := rfract (rfract'high downto
rfract'high - (fraction_width+1+multguard));
sticky := or_reduce (rfract (rfract'high-(fraction_width+1+multguard)
downto 0));
-- add the exponents
rexpon := (exponl(exponl'high)&exponl) + (exponr(exponr'high)&exponr) +1;
-- normalize
fpresult := normalize (fract => sfract,
expon => rexpon,
sign => fp_sign,
sticky => sticky,
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => multguard);
end if;
return fpresult;
end function multiply;
function short_divide (
lx, rx : UNSIGNED)
return UNSIGNED is
-- This is a special divider for the floating point routines.
-- For a true unsigned divider, "stages" needs to = lx'high
constant stages : INTEGER := lx'high - rx'high; -- number of stages
variable partial : UNSIGNED (lx'range);
variable q : UNSIGNED (stages downto 0);
variable partial_argl : SIGNED (rx'high + 2 downto 0);
variable partial_arg : SIGNED (rx'high + 2 downto 0);
begin
partial := lx;
for i in stages downto 0 loop
partial_argl := resize ("0" & SIGNED (partial(lx'high downto i)),
partial_argl'length);
partial_arg := partial_argl - SIGNED ("0" & rx);
if (partial_arg (partial_arg'high) = '1') then -- negative
q(i) := '0';
else
q(i) := '1';
partial (lx'high+i-stages downto lx'high+i-stages-rx'high) :=
UNSIGNED (partial_arg(rx'range));
end if;
end loop;
-- to make the output look like that of the unsigned IEEE divide.
return resize (q, lx'length);
end function short_divide;
-- 1/X function. Needed for algorithm development.
function reciprocal (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(arg'low, arg'low); -- length of FP output fraction
constant exponent_width : NATURAL := arg'high; -- length of FP output exponent
constant divguard : NATURAL := guard; -- guard bits
function onedivy (
arg : UNSIGNED)
return UNSIGNED is
variable q : UNSIGNED((2*arg'high)+1 downto 0);
variable one : UNSIGNED (q'range);
begin
one := (others => '0');
one(one'high) := '1';
q := short_divide (one, arg); -- Unsigned divide
return resize (q, arg'length+1);
end function onedivy;
variable fptype : valid_fpstate;
variable expon : SIGNED (exponent_width-1 downto 0); -- exponents
variable denorm_offset : NATURAL range 0 to 2;
variable fract : UNSIGNED (fraction_width downto 0);
variable fractg : UNSIGNED (fraction_width+divguard downto 0);
variable sfract : UNSIGNED (fraction_width+1+divguard downto 0); -- result fraction
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- reciprocal
fptype := classfp(arg, check_error);
classcase : case fptype is
when isx =>
fpresult := (others => 'X');
when nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_inf | neg_inf => -- 1/inf, return 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
when neg_zero | pos_zero => -- 1/0
report float_pkg'instance_name
& "RECIPROCAL: Floating Point divide by zero"
severity error;
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
when others =>
if (fptype = pos_denormal or fptype = neg_denormal)
and ((arg (-1) or arg(-2)) /= '1') then
-- 1/denormal = infinity, with the exception of 2**-expon_base
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
fpresult (exponent_width) := to_x01 (arg (exponent_width));
else
break_number (
arg => arg,
fptyp => fptype,
denormalize => denormalize,
fract => fract,
expon => expon);
fractg := (others => '0');
if (fptype = pos_denormal or fptype = neg_denormal) then
-- The reciprocal of a denormal number is typically zero,
-- except for two special cases which are trapped here.
if (to_x01(arg (-1)) = '1') then
fractg (fractg'high downto divguard+1) :=
fract (fract'high-1 downto 0); -- Shift to not denormal
denorm_offset := 1; -- add 1 to exponent compensate
else -- arg(-2) = '1'
fractg (fractg'high downto divguard+2) :=
fract (fract'high-2 downto 0); -- Shift to not denormal
denorm_offset := 2; -- add 2 to exponent compensate
end if;
else
fractg (fractg'high downto divguard) := fract;
denorm_offset := 0;
end if;
expon := - expon - 3 + denorm_offset;
sfract := onedivy (fractg);
-- normalize
fpresult := normalize (fract => sfract,
expon => expon,
sign => arg(exponent_width),
sticky => '1',
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => divguard);
end if;
end case classcase;
return fpresult;
end function reciprocal;
-- floating point division
function divide (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
constant divguard : NATURAL := guard; -- division guard bits
variable lfptype, rfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable ulfract, urfract : UNSIGNED (fraction_width downto 0);
variable fractl : UNSIGNED ((2*(fraction_width+divguard)+1) downto 0); -- left
variable fractr : UNSIGNED (fraction_width+divguard downto 0); -- right
variable rfract : UNSIGNED (fractl'range); -- result fraction
variable sfract : UNSIGNED (fraction_width+1+divguard downto 0); -- result fraction
variable exponl, exponr : SIGNED (exponent_width-1 downto 0); -- exponents
variable rexpon : SIGNED (exponent_width downto 0); -- result exponent
variable fp_sign : STD_ULOGIC; -- sign of result
variable shifty : INTEGER; -- denormal number shift
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- divide
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
classcase : case rfptype is
when isx =>
fpresult := (others => 'X');
when nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_inf | neg_inf =>
if lfptype = pos_inf or lfptype = neg_inf -- inf / inf
or lfptype = quiet_nan or lfptype = nan then
-- Return quiet NAN, IEEE754-1985-7.1,4
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
else -- x / inf = 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
when pos_zero | neg_zero =>
if lfptype = pos_zero or lfptype = neg_zero -- 0 / 0
or lfptype = quiet_nan or lfptype = nan then
-- Return quiet NAN, IEEE754-1985-7.1,4
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
report float_pkg'instance_name
& "DIVIDE: Floating Point divide by zero"
severity error;
-- Infinity, define in 754-1985-7.2
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
when others =>
fp_sign := l(l'high) xor r(r'high); -- sign
classcase2 : case lfptype is
when isx =>
fpresult := (others => 'X');
when nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_inf | neg_inf => -- inf / x = inf
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
fpresult(exponent_width) := fp_sign;
when pos_zero | neg_zero => -- 0 / X = 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
when others =>
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
lfptype := classfp (lresize, false); -- errors already checked
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rfptype := classfp (rresize, false); -- errors already checked
fractl := (others => '0');
break_number (
arg => lresize,
fptyp => lfptype,
denormalize => denormalize,
fract => ulfract,
expon => exponl);
fractl (fractl'high downto fractl'high-fraction_width) := ulfract;
-- right side
fractr := (others => '0');
break_number (
arg => rresize,
fptyp => rfptype,
denormalize => denormalize,
fract => urfract,
expon => exponr);
fractr (fraction_width+divguard downto divguard) := urfract;
rexpon := (exponl(exponl'high)&exponl)
- (exponr(exponr'high)&exponr) - 2;
if (rfptype = pos_denormal or rfptype = neg_denormal) then
-- Do the shifting here not after. That way we have a smaller
-- shifter, and need a smaller divider, because the top
-- bit in the divisor will always be a "1".
shifty := fraction_width - find_leftmost(urfract, '1');
fractr := shift_left (fractr, shifty);
rexpon := rexpon + shifty;
end if;
-- divide
rfract := short_divide (fractl, fractr); -- unsigned divide
sfract := rfract (sfract'range); -- lower bits
-- normalize
fpresult := normalize (fract => sfract,
expon => rexpon,
sign => fp_sign,
sticky => '1',
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => divguard);
end case classcase2;
end case classcase;
return fpresult;
end function divide;
-- division by a power of 2
function dividebyp2 (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lfptype, rfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable ulfract, urfract : UNSIGNED (fraction_width downto 0);
variable exponl, exponr : SIGNED(exponent_width-1 downto 0); -- exponents
variable rexpon : SIGNED(exponent_width downto 0); -- result exponent
variable fp_sign : STD_ULOGIC; -- sign of result
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- divisionbyp2
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
classcase : case rfptype is
when isx =>
fpresult := (others => 'X');
when nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_inf | neg_inf =>
if lfptype = pos_inf or lfptype = neg_inf then -- inf / inf
-- Return quiet NAN, IEEE754-1985-7.1,4
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
else -- x / inf = 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
when pos_zero | neg_zero =>
if lfptype = pos_zero or lfptype = neg_zero then -- 0 / 0
-- Return quiet NAN, IEEE754-1985-7.1,4
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
report float_pkg'instance_name
& "DIVIDEBYP2: Floating Point divide by zero"
severity error;
-- Infinity, define in 754-1985-7.2
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
when others =>
classcase2 : case lfptype is
when isx =>
fpresult := (others => 'X');
when nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_inf | neg_inf => -- inf / x = inf
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
fpresult(exponent_width) := l(exponent_width) xor r(exponent_width);
when pos_zero | neg_zero => -- 0 / X = 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
when others =>
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
lfptype := classfp (lresize, false); -- errors already checked
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rfptype := classfp (rresize, false); -- errors already checked
fp_sign := l(l'high) xor r(r'high); -- sign
break_number (
arg => lresize,
fptyp => lfptype,
denormalize => denormalize,
fract => ulfract,
expon => exponl);
-- right side
break_number (
arg => rresize,
fptyp => rfptype,
denormalize => denormalize,
fract => urfract,
expon => exponr);
assert (or_reduce (urfract (fraction_width-1 downto 0)) = '0')
report float_pkg'instance_name
& "DIVIDEBYP2: "
& "Dividebyp2 called with a non power of two divisor"
severity error;
rexpon := (exponl(exponl'high)&exponl)
- (exponr(exponr'high)&exponr) - 1;
-- normalize
fpresult := normalize (fract => ulfract,
expon => rexpon,
sign => fp_sign,
sticky => '1',
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => 0);
end case classcase2;
end case classcase;
return fpresult;
end function dividebyp2;
-- Multiply accumulate result = l*r + c
function mac (
l, r, c : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL :=
-mine (mine(l'low, r'low), c'low); -- length of FP output fraction
constant exponent_width : NATURAL :=
maximum (maximum(l'high, r'high), c'high); -- length of FP output exponent
variable lfptype, rfptype, cfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable fractl, fractr : UNSIGNED (fraction_width downto 0); -- fractions
variable fractx : UNSIGNED (fraction_width+guard downto 0);
variable fractc, fracts : UNSIGNED (fraction_width+1+guard downto 0);
variable rfract : UNSIGNED ((2*(fraction_width))+1 downto 0); -- result fraction
variable sfract, ufract : UNSIGNED (fraction_width+1+guard downto 0); -- result fraction
variable exponl, exponr, exponc : SIGNED (exponent_width-1 downto 0); -- exponents
variable shiftx : SIGNED (exponent_width downto 0); -- shift fractions
variable rexpon, rexpon2 : SIGNED (exponent_width downto 0); -- result exponent
variable fp_sign : STD_ULOGIC; -- sign of result
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
variable cresize : UNRESOLVED_float (exponent_width downto -fraction_width - guard);
variable leftright : BOOLEAN; -- left or right used
variable sticky : STD_ULOGIC; -- Holds precision for rounding
begin -- multiply
if (fraction_width = 0 or l'length < 7 or r'length < 7 or c'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
cfptype := classfp (c, check_error);
end if;
if (lfptype = isx or rfptype = isx or cfptype = isx) then
fpresult := (others => 'X');
elsif (lfptype = nan or lfptype = quiet_nan or
rfptype = nan or rfptype = quiet_nan or
cfptype = nan or cfptype = quiet_nan) then
-- Return quiet NAN, IEEE754-1985-7.1,1
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (((lfptype = pos_inf or lfptype = neg_inf) and
(rfptype = pos_zero or rfptype = neg_zero)) or
((rfptype = pos_inf or rfptype = neg_inf) and
(lfptype = pos_zero or lfptype = neg_zero))) then -- 0 * inf
-- Return quiet NAN, IEEE754-1985-7.1,3
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (lfptype = pos_inf or rfptype = pos_inf
or lfptype = neg_inf or rfptype = neg_inf -- x * inf = inf
or cfptype = neg_inf or cfptype = pos_inf) then -- x + inf = inf
fpresult := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
-- figure out the sign
fpresult (exponent_width) := l(l'high) xor r(r'high);
else
fp_sign := l(l'high) xor r(r'high); -- figure out the sign
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
lfptype := classfp (lresize, false); -- errors already checked
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rfptype := classfp (rresize, false); -- errors already checked
cresize := resize (arg => to_x01(c),
exponent_width => exponent_width,
fraction_width => -cresize'low,
denormalize_in => denormalize,
denormalize => denormalize);
cfptype := classfp (cresize, false); -- errors already checked
break_number (
arg => lresize,
fptyp => lfptype,
denormalize => denormalize,
fract => fractl,
expon => exponl);
break_number (
arg => rresize,
fptyp => rfptype,
denormalize => denormalize,
fract => fractr,
expon => exponr);
break_number (
arg => cresize,
fptyp => cfptype,
denormalize => denormalize,
fract => fractx,
expon => exponc);
-- multiply
rfract := fractl * fractr; -- Multiply the fraction
-- add the exponents
rexpon := (exponl(exponl'high)&exponl) + (exponr(exponr'high)&exponr) +1;
shiftx := rexpon - exponc;
if shiftx < -fractl'high then
rexpon2 := exponc(exponent_width-1) & exponc;
fractc := "0" & fractx;
fracts := (others => '0');
sticky := or_reduce (rfract);
elsif shiftx < 0 then
shiftx := - shiftx;
fracts := shift_right (rfract (rfract'high downto rfract'high
- fracts'length+1),
to_integer(shiftx));
fractc := "0" & fractx;
rexpon2 := exponc(exponent_width-1) & exponc;
leftright := false;
sticky := or_reduce (rfract (to_integer(shiftx)+rfract'high
- fracts'length downto 0));
elsif shiftx = 0 then
rexpon2 := exponc(exponent_width-1) & exponc;
sticky := or_reduce (rfract (rfract'high - fractc'length downto 0));
if rfract (rfract'high downto rfract'high - fractc'length+1) > fractx
then
fractc := "0" & fractx;
fracts := rfract (rfract'high downto rfract'high
- fracts'length+1);
leftright := false;
else
fractc := rfract (rfract'high downto rfract'high
- fractc'length+1);
fracts := "0" & fractx;
leftright := true;
end if;
elsif shiftx > fractx'high then
rexpon2 := rexpon;
fracts := (others => '0');
fractc := rfract (rfract'high downto rfract'high - fractc'length+1);
leftright := true;
sticky := or_reduce (fractx & rfract (rfract'high - fractc'length
downto 0));
else -- fractx'high > shiftx > 0
rexpon2 := rexpon;
fracts := "0" & shift_right (fractx, to_integer (shiftx));
fractc := rfract (rfract'high downto rfract'high - fractc'length+1);
leftright := true;
sticky := or_reduce (fractx (to_integer (shiftx) downto 0)
& rfract (rfract'high - fractc'length downto 0));
end if;
fracts (0) := fracts (0) or sticky; -- Or the sticky bit into the LSB
if fp_sign = to_X01(c(c'high)) then
ufract := fractc + fracts;
fp_sign := fp_sign;
else -- signs are different
ufract := fractc - fracts; -- always positive result
if leftright then -- Figure out which sign to use
fp_sign := fp_sign;
else
fp_sign := c(c'high);
end if;
end if;
-- normalize
fpresult := normalize (fract => ufract,
expon => rexpon2,
sign => fp_sign,
sticky => sticky,
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => guard);
end if;
return fpresult;
end function mac;
-- "rem" function
function remainder (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
constant divguard : NATURAL := guard; -- division guard bits
variable lfptype, rfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable ulfract, urfract : UNSIGNED (fraction_width downto 0);
variable fractr, fractl : UNSIGNED (fraction_width+divguard downto 0); -- right
variable rfract : UNSIGNED (fractr'range); -- result fraction
variable sfract : UNSIGNED (fraction_width+divguard downto 0); -- result fraction
variable exponl, exponr : SIGNED (exponent_width-1 downto 0); -- exponents
variable rexpon : SIGNED (exponent_width downto 0); -- result exponent
variable fp_sign : STD_ULOGIC; -- sign of result
variable shifty : INTEGER; -- denormal number shift
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- remainder
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
if (lfptype = isx or rfptype = isx) then
fpresult := (others => 'X');
elsif (lfptype = nan or lfptype = quiet_nan)
or (rfptype = nan or rfptype = quiet_nan)
-- Return quiet NAN, IEEE754-1985-7.1,1
or (lfptype = pos_inf or lfptype = neg_inf) -- inf rem x
-- Return quiet NAN, IEEE754-1985-7.1,5
or (rfptype = pos_zero or rfptype = neg_zero) then -- x rem 0
-- Return quiet NAN, IEEE754-1985-7.1,5
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (rfptype = pos_inf or rfptype = neg_inf) then -- x rem inf = 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (abs(l) < abs(r)) then
fpresult := l;
else
fp_sign := to_X01(l(l'high)); -- sign
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
lfptype := classfp (lresize, false); -- errors already checked
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rfptype := classfp (rresize, false); -- errors already checked
fractl := (others => '0');
break_number (
arg => lresize,
fptyp => lfptype,
denormalize => denormalize,
fract => ulfract,
expon => exponl);
fractl (fraction_width+divguard downto divguard) := ulfract;
-- right side
fractr := (others => '0');
break_number (
arg => rresize,
fptyp => rfptype,
denormalize => denormalize,
fract => urfract,
expon => exponr);
fractr (fraction_width+divguard downto divguard) := urfract;
rexpon := (exponr(exponr'high)&exponr);
shifty := to_integer(exponl - rexpon);
if (shifty > 0) then
fractr := shift_right (fractr, shifty);
rexpon := rexpon + shifty;
end if;
if (fractr /= 0) then
-- rem
rfract := fractl rem fractr; -- unsigned rem
sfract := rfract (sfract'range); -- lower bits
-- normalize
fpresult := normalize (fract => sfract,
expon => rexpon,
sign => fp_sign,
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => divguard);
else
-- If we shift "fractr" so far that it becomes zero, return zero.
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
end if;
return fpresult;
end function remainder;
-- "mod" function
function modulo (
l, r : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant guard : NATURAL := float_guard_bits; -- number of guard bits
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := - mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lfptype, rfptype : valid_fpstate;
variable fpresult : UNRESOLVED_float (exponent_width downto -fraction_width);
variable remres : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- remainder
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
lfptype := isx;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
if (lfptype = isx or rfptype = isx) then
fpresult := (others => 'X');
elsif (lfptype = nan or lfptype = quiet_nan)
or (rfptype = nan or rfptype = quiet_nan)
-- Return quiet NAN, IEEE754-1985-7.1,1
or (lfptype = pos_inf or lfptype = neg_inf) -- inf rem x
-- Return quiet NAN, IEEE754-1985-7.1,5
or (rfptype = pos_zero or rfptype = neg_zero) then -- x rem 0
-- Return quiet NAN, IEEE754-1985-7.1,5
fpresult := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (rfptype = pos_inf or rfptype = neg_inf) then -- x rem inf = 0
fpresult := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
remres := remainder (l => abs(l),
r => abs(r),
round_style => round_style,
guard => guard,
check_error => false,
denormalize => denormalize);
-- MOD is the same as REM, but you do something different with
-- negative values
if (is_negative (l)) then
remres := - remres;
end if;
if (is_negative (l) = is_negative (r) or remres = 0) then
fpresult := remres;
else
fpresult := add (l => remres,
r => r,
round_style => round_style,
guard => guard,
check_error => false,
denormalize => denormalize);
end if;
end if;
return fpresult;
end function modulo;
-- Square root of a floating point number. Done using Newton's Iteration.
function sqrt (
arg : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style;
constant guard : NATURAL := float_guard_bits;
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_float is
constant fraction_width : NATURAL := guard-arg'low; -- length of FP output fraction
constant exponent_width : NATURAL := arg'high; -- length of FP output exponent
variable sign : STD_ULOGIC;
variable fpresult : float (arg'range);
variable fptype : valid_fpstate;
variable iexpon : SIGNED(exponent_width-1 downto 0); -- exponents
variable expon : SIGNED(exponent_width downto 0); -- exponents
variable ufact : ufixed (0 downto arg'low);
variable fact : ufixed (2 downto -fraction_width); -- fraction
variable resb : ufixed (fact'high+1 downto fact'low);
begin -- square root
fptype := Classfp (arg, check_error);
classcase : case fptype is
when isx =>
fpresult := (others => 'X');
when nan | quiet_nan |
-- Return quiet NAN, IEEE754-1985-7.1,1
neg_normal | neg_denormal | neg_inf => -- sqrt (neg)
-- Return quiet NAN, IEEE754-1985-7.1.6
fpresult := qnanfp (fraction_width => fraction_width-guard,
exponent_width => exponent_width);
when pos_inf => -- Sqrt (inf), return infinity
fpresult := pos_inffp (fraction_width => fraction_width-guard,
exponent_width => exponent_width);
when pos_zero => -- return 0
fpresult := zerofp (fraction_width => fraction_width-guard,
exponent_width => exponent_width);
when neg_zero => -- IEEE754-1985-6.3 return -0
fpresult := neg_zerofp (fraction_width => fraction_width-guard,
exponent_width => exponent_width);
when others =>
break_number (arg => arg,
denormalize => denormalize,
check_error => false,
fract => ufact,
expon => iexpon,
sign => sign);
expon := resize (iexpon+1, expon'length); -- get exponent
fact := resize (ufact, fact'high, fact'low);
if (expon(0) = '1') then
fact := fact sla 1; -- * 2.0
end if;
expon := shift_right (expon, 1); -- exponent/2
-- Newton's iteration - root := (1 + arg) / 2
resb := (fact + 1) sra 1;
for j in 0 to fraction_width/4 loop
-- root := (root + (arg/root))/2
resb := resize (arg => (resb + (fact/resb)) sra 1,
left_index => resb'high,
right_index => resb'low,
round_style => fixed_truncate,
overflow_style => fixed_wrap);
end loop;
fpresult := normalize (fract => resb,
expon => expon-1,
sign => '0',
exponent_width => arg'high,
fraction_width => -arg'low,
round_style => round_style,
denormalize => denormalize,
nguard => guard);
end case classcase;
return fpresult;
end function sqrt;
function Is_Negative (arg : UNRESOLVED_float) return BOOLEAN is
begin
return (to_x01(arg(arg'high)) = '1');
end function Is_Negative;
-- compare functions
-- =, /=, >=, <=, <, >
function eq ( -- equal =
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN is
variable lfptype, rfptype : valid_fpstate;
variable is_equal, is_unordered : BOOLEAN;
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- equal
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return false;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
end if;
if (lfptype = neg_zero or lfptype = pos_zero) and
(rfptype = neg_zero or rfptype = pos_zero) then
is_equal := true;
else
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
is_equal := (to_slv(lresize) = to_slv(rresize));
end if;
if (check_error) then
is_unordered := Unordered (x => l,
y => r);
else
is_unordered := false;
end if;
return is_equal and not is_unordered;
end function eq;
function lt ( -- less than <
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lfptype, rfptype : valid_fpstate;
variable expl, expr : UNSIGNED (exponent_width-1 downto 0);
variable fractl, fractr : UNSIGNED (fraction_width-1 downto 0);
variable is_less_than, is_unordered : BOOLEAN;
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
is_less_than := false;
else
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
if to_x01(l(l'high)) = to_x01(r(r'high)) then -- sign bits
expl := UNSIGNED(lresize(exponent_width-1 downto 0));
expr := UNSIGNED(rresize(exponent_width-1 downto 0));
if expl = expr then
fractl := UNSIGNED (to_slv(lresize(-1 downto -fraction_width)));
fractr := UNSIGNED (to_slv(rresize(-1 downto -fraction_width)));
if to_x01(l(l'high)) = '0' then -- positive number
is_less_than := (fractl < fractr);
else
is_less_than := (fractl > fractr); -- negative
end if;
else
if to_x01(l(l'high)) = '0' then -- positive number
is_less_than := (expl < expr);
else
is_less_than := (expl > expr); -- negative
end if;
end if;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
if (lfptype = neg_zero and rfptype = pos_zero) then
is_less_than := false; -- -0 < 0 returns false.
else
is_less_than := (to_x01(l(l'high)) > to_x01(r(r'high)));
end if;
end if;
end if;
if check_error then
is_unordered := Unordered (x => l,
y => r);
else
is_unordered := false;
end if;
return is_less_than and not is_unordered;
end function lt;
function gt ( -- greater than >
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lfptype, rfptype : valid_fpstate;
variable expl, expr : UNSIGNED (exponent_width-1 downto 0);
variable fractl, fractr : UNSIGNED (fraction_width-1 downto 0);
variable is_greater_than : BOOLEAN;
variable is_unordered : BOOLEAN;
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- greater_than
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
is_greater_than := false;
else
lresize := resize (arg => to_x01(l),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
rresize := resize (arg => to_x01(r),
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => denormalize,
denormalize => denormalize);
if to_x01(l(l'high)) = to_x01(r(r'high)) then -- sign bits
expl := UNSIGNED(lresize(exponent_width-1 downto 0));
expr := UNSIGNED(rresize(exponent_width-1 downto 0));
if expl = expr then
fractl := UNSIGNED (to_slv(lresize(-1 downto -fraction_width)));
fractr := UNSIGNED (to_slv(rresize(-1 downto -fraction_width)));
if to_x01(l(l'high)) = '0' then -- positive number
is_greater_than := fractl > fractr;
else
is_greater_than := fractl < fractr; -- negative
end if;
else
if to_x01(l(l'high)) = '0' then -- positive number
is_greater_than := expl > expr;
else
is_greater_than := expl < expr; -- negative
end if;
end if;
else
lfptype := classfp (l, check_error);
rfptype := classfp (r, check_error);
if (lfptype = pos_zero and rfptype = neg_zero) then
is_greater_than := false; -- 0 > -0 returns false.
else
is_greater_than := to_x01(l(l'high)) < to_x01(r(r'high));
end if;
end if;
end if;
if check_error then
is_unordered := Unordered (x => l,
y => r);
else
is_unordered := false;
end if;
return is_greater_than and not is_unordered;
end function gt;
-- purpose: /= function
function ne ( -- not equal /=
l, r : UNRESOLVED_float;
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN is
variable is_equal, is_unordered : BOOLEAN;
begin
is_equal := eq (l => l,
r => r,
check_error => false,
denormalize => denormalize);
if check_error then
is_unordered := Unordered (x => l,
y => r);
else
is_unordered := false;
end if;
return not (is_equal and not is_unordered);
end function ne;
function le ( -- less than or equal to <=
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN is
variable is_greater_than, is_unordered : BOOLEAN;
begin
is_greater_than := gt (l => l,
r => r,
check_error => false,
denormalize => denormalize);
if check_error then
is_unordered := Unordered (x => l,
y => r);
else
is_unordered := false;
end if;
return not is_greater_than and not is_unordered;
end function le;
function ge ( -- greater than or equal to >=
l, r : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error;
constant denormalize : BOOLEAN := float_denormalize)
return BOOLEAN is
variable is_less_than, is_unordered : BOOLEAN;
begin
is_less_than := lt (l => l,
r => r,
check_error => false,
denormalize => denormalize);
if check_error then
is_unordered := Unordered (x => l,
y => r);
else
is_unordered := false;
end if;
return not is_less_than and not is_unordered;
end function ge;
function \?=\ (L, R : UNRESOLVED_float) return STD_ULOGIC is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lfptype, rfptype : valid_fpstate;
variable is_equal, is_unordered : STD_ULOGIC;
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- ?=
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return 'X';
else
lfptype := classfp (l, float_check_error);
rfptype := classfp (r, float_check_error);
end if;
if (lfptype = neg_zero or lfptype = pos_zero) and
(rfptype = neg_zero or rfptype = pos_zero) then
is_equal := '1';
else
lresize := resize (arg => l,
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => float_denormalize,
denormalize => float_denormalize);
rresize := resize (arg => r,
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => float_denormalize,
denormalize => float_denormalize);
is_equal := \?=\ (to_suv(lresize), to_suv(rresize));
end if;
if (float_check_error) then
if (lfptype = nan or lfptype = quiet_nan or
rfptype = nan or rfptype = quiet_nan) then
is_unordered := '1';
else
is_unordered := '0';
end if;
else
is_unordered := '0';
end if;
return is_equal and not is_unordered;
end function \?=\;
function \?/=\ (L, R : UNRESOLVED_float) return STD_ULOGIC is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lfptype, rfptype : valid_fpstate;
variable is_equal, is_unordered : STD_ULOGIC;
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin -- ?/=
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return 'X';
else
lfptype := classfp (l, float_check_error);
rfptype := classfp (r, float_check_error);
end if;
if (lfptype = neg_zero or lfptype = pos_zero) and
(rfptype = neg_zero or rfptype = pos_zero) then
is_equal := '1';
else
lresize := resize (arg => l,
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => float_denormalize,
denormalize => float_denormalize);
rresize := resize (arg => r,
exponent_width => exponent_width,
fraction_width => fraction_width,
denormalize_in => float_denormalize,
denormalize => float_denormalize);
is_equal := \?=\ (to_suv(lresize), to_suv(rresize));
end if;
if (float_check_error) then
if (lfptype = nan or lfptype = quiet_nan or
rfptype = nan or rfptype = quiet_nan) then
is_unordered := '1';
else
is_unordered := '0';
end if;
else
is_unordered := '0';
end if;
return not (is_equal and not is_unordered);
end function \?/=\;
function \?>\ (L, R : UNRESOLVED_float) return STD_ULOGIC is
constant fraction_width : NATURAL := -mine(l'low, r'low);
variable founddash : BOOLEAN := false;
begin
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return 'X';
else
for i in L'range loop
if L(i) = '-' then
founddash := true;
end if;
end loop;
for i in R'range loop
if R(i) = '-' then
founddash := true;
end if;
end loop;
if founddash then
report float_pkg'instance_name
& " ""?>"": '-' found in compare string"
severity error;
return 'X';
elsif is_x(l) or is_x(r) then
return 'X';
elsif l > r then
return '1';
else
return '0';
end if;
end if;
end function \?>\;
function \?>=\ (L, R : UNRESOLVED_float) return STD_ULOGIC is
constant fraction_width : NATURAL := -mine(l'low, r'low);
variable founddash : BOOLEAN := false;
begin
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return 'X';
else
for i in L'range loop
if L(i) = '-' then
founddash := true;
end if;
end loop;
for i in R'range loop
if R(i) = '-' then
founddash := true;
end if;
end loop;
if founddash then
report float_pkg'instance_name
& " ""?>="": '-' found in compare string"
severity error;
return 'X';
elsif is_x(l) or is_x(r) then
return 'X';
elsif l >= r then
return '1';
else
return '0';
end if;
end if;
end function \?>=\;
function \?<\ (L, R : UNRESOLVED_float) return STD_ULOGIC is
constant fraction_width : NATURAL := -mine(l'low, r'low);
variable founddash : BOOLEAN := false;
begin
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return 'X';
else
for i in L'range loop
if L(i) = '-' then
founddash := true;
end if;
end loop;
for i in R'range loop
if R(i) = '-' then
founddash := true;
end if;
end loop;
if founddash then
report float_pkg'instance_name
& " ""?<"": '-' found in compare string"
severity error;
return 'X';
elsif is_x(l) or is_x(r) then
return 'X';
elsif l < r then
return '1';
else
return '0';
end if;
end if;
end function \?<\;
function \?<=\ (L, R : UNRESOLVED_float) return STD_ULOGIC is
constant fraction_width : NATURAL := -mine(l'low, r'low);
variable founddash : BOOLEAN := false;
begin
if (fraction_width = 0 or l'length < 7 or r'length < 7) then
return 'X';
else
for i in L'range loop
if L(i) = '-' then
founddash := true;
end if;
end loop;
for i in R'range loop
if R(i) = '-' then
founddash := true;
end if;
end loop;
if founddash then
report float_pkg'instance_name
& " ""?<="": '-' found in compare string"
severity error;
return 'X';
elsif is_x(l) or is_x(r) then
return 'X';
elsif l <= r then
return '1';
else
return '0';
end if;
end if;
end function \?<=\;
function std_match (L, R : UNRESOLVED_float) return BOOLEAN is
begin
if (L'high = R'high and L'low = R'low) then
return std_match(to_suv(L), to_suv(R));
else
report float_pkg'instance_name
& "STD_MATCH: L'RANGE /= R'RANGE, returning FALSE"
severity warning;
return false;
end if;
end function std_match;
function find_rightmost (arg : UNRESOLVED_float; y : STD_ULOGIC) return INTEGER is
begin
for_loop : for i in arg'reverse_range loop
if \?=\ (arg(i), y) = '1' then
return i;
end if;
end loop;
return arg'high+1; -- return out of bounds 'high
end function find_rightmost;
function find_leftmost (arg : UNRESOLVED_float; y : STD_ULOGIC) return INTEGER is
begin
for_loop : for i in arg'range loop
if \?=\ (arg(i), y) = '1' then
return i;
end if;
end loop;
return arg'low-1; -- return out of bounds 'low
end function find_leftmost;
-- These override the defaults for the compare operators.
function "=" (l, r : UNRESOLVED_float) return BOOLEAN is
begin
return eq(l, r);
end function "=";
function "/=" (l, r : UNRESOLVED_float) return BOOLEAN is
begin
return ne(l, r);
end function "/=";
function ">=" (l, r : UNRESOLVED_float) return BOOLEAN is
begin
return ge(l, r);
end function ">=";
function "<=" (l, r : UNRESOLVED_float) return BOOLEAN is
begin
return le(l, r);
end function "<=";
function ">" (l, r : UNRESOLVED_float) return BOOLEAN is
begin
return gt(l, r);
end function ">";
function "<" (l, r : UNRESOLVED_float) return BOOLEAN is
begin
return lt(l, r);
end function "<";
-- purpose: maximum of two numbers (overrides default)
function maximum (
L, R : UNRESOLVED_float)
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin
if ((L'length < 1) or (R'length < 1)) then return NAFP;
end if;
lresize := resize (l, exponent_width, fraction_width);
rresize := resize (r, exponent_width, fraction_width);
if lresize > rresize then return lresize;
else return rresize;
end if;
end function maximum;
function minimum (
L, R : UNRESOLVED_float)
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(l'low, r'low); -- length of FP output fraction
constant exponent_width : NATURAL := maximum(l'high, r'high); -- length of FP output exponent
variable lresize, rresize : UNRESOLVED_float (exponent_width downto -fraction_width);
begin
if ((L'length < 1) or (R'length < 1)) then return NAFP;
end if;
lresize := resize (l, exponent_width, fraction_width);
rresize := resize (r, exponent_width, fraction_width);
if lresize > rresize then return rresize;
else return lresize;
end if;
end function minimum;
-----------------------------------------------------------------------------
-- conversion functions
-----------------------------------------------------------------------------
-- Converts a floating point number of one format into another format
function resize (
arg : UNRESOLVED_float; -- Floating point input
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant in_fraction_width : NATURAL := -arg'low; -- length of FP output fraction
constant in_exponent_width : NATURAL := arg'high; -- length of FP output exponent
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
-- result value
variable fptype : valid_fpstate;
variable expon_in : SIGNED (in_exponent_width-1 downto 0);
variable fract_in : UNSIGNED (in_fraction_width downto 0);
variable round : BOOLEAN;
variable expon_out : SIGNED (exponent_width-1 downto 0); -- output fract
variable fract_out : UNSIGNED (fraction_width downto 0); -- output fract
variable passguard : NATURAL;
begin
fptype := classfp(arg, check_error);
if ((fptype = pos_denormal or fptype = neg_denormal) and denormalize_in
and (in_exponent_width < exponent_width
or in_fraction_width < fraction_width))
or in_exponent_width > exponent_width
or in_fraction_width > fraction_width then
-- size reduction
classcase : case fptype is
when isx =>
result := (others => 'X');
when nan | quiet_nan =>
result := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_inf =>
result := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
when neg_inf =>
result := neg_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
when pos_zero | neg_zero =>
result := zerofp (fraction_width => fraction_width, -- hate -0
exponent_width => exponent_width);
when others =>
break_number (
arg => arg,
fptyp => fptype,
denormalize => denormalize_in,
fract => fract_in,
expon => expon_in);
if fraction_width > in_fraction_width and denormalize_in then
-- You only get here if you have a denormal input
fract_out := (others => '0'); -- pad with zeros
fract_out (fraction_width downto
fraction_width - in_fraction_width) := fract_in;
result := normalize (
fract => fract_out,
expon => expon_in,
sign => arg(arg'high),
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => 0);
else
result := normalize (
fract => fract_in,
expon => expon_in,
sign => arg(arg'high),
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => in_fraction_width - fraction_width);
end if;
end case classcase;
else -- size increase or the same size
if exponent_width > in_exponent_width then
expon_in := SIGNED(arg (in_exponent_width-1 downto 0));
if fptype = pos_zero or fptype = neg_zero then
result (exponent_width-1 downto 0) := (others => '0');
elsif expon_in = -1 then -- inf or nan (shorts out check_error)
result (exponent_width-1 downto 0) := (others => '1');
else
-- invert top BIT
expon_in(expon_in'high) := not expon_in(expon_in'high);
expon_out := resize (expon_in, expon_out'length); -- signed expand
-- Flip it back.
expon_out(expon_out'high) := not expon_out(expon_out'high);
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon_out);
end if;
result (exponent_width) := arg (in_exponent_width); -- sign
else -- exponent_width = in_exponent_width
result (exponent_width downto 0) := arg (in_exponent_width downto 0);
end if;
if fraction_width > in_fraction_width then
result (-1 downto -fraction_width) := (others => '0'); -- zeros
result (-1 downto -in_fraction_width) :=
arg (-1 downto -in_fraction_width);
else -- fraction_width = in_fraciton_width
result (-1 downto -fraction_width) :=
arg (-1 downto -in_fraction_width);
end if;
end if;
return result;
end function resize;
function resize (
arg : UNRESOLVED_float; -- floating point input
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := resize (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style,
check_error => check_error,
denormalize_in => denormalize_in,
denormalize => denormalize);
return result;
end if;
end function resize;
function to_float32 (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float32 is
begin
return resize (arg => arg,
exponent_width => float32'high,
fraction_width => -float32'low,
round_style => round_style,
check_error => check_error,
denormalize_in => denormalize_in,
denormalize => denormalize);
end function to_float32;
function to_float64 (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float64 is
begin
return resize (arg => arg,
exponent_width => float64'high,
fraction_width => -float64'low,
round_style => round_style,
check_error => check_error,
denormalize_in => denormalize_in,
denormalize => denormalize);
end function to_float64;
function to_float128 (
arg : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error;
constant denormalize_in : BOOLEAN := float_denormalize; -- Use IEEE extended FP
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float128 is
begin
return resize (arg => arg,
exponent_width => float128'high,
fraction_width => -float128'low,
round_style => round_style,
check_error => check_error,
denormalize_in => denormalize_in,
denormalize => denormalize);
end function to_float128;
-- to_float (Real)
-- typically not Synthesizable unless the input is a constant.
function to_float (
arg : REAL;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable arg_real : REAL; -- Real version of argument
variable validfp : boundary_type; -- Check for valid results
variable exp : INTEGER; -- Integer version of exponent
variable expon : UNSIGNED (exponent_width - 1 downto 0);
-- Unsigned version of exp.
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable fract : UNSIGNED (fraction_width-1 downto 0);
variable frac : REAL; -- Real version of fraction
constant roundfrac : REAL := 2.0 ** (-2 - fract'high); -- used for rounding
variable round : BOOLEAN; -- to round or not to round
begin
result := (others => '0');
arg_real := arg;
if arg_real < 0.0 then
result (exponent_width) := '1';
arg_real := - arg_real; -- Make it positive.
else
result (exponent_width) := '0';
end if;
test_boundary (arg => arg_real,
fraction_width => fraction_width,
exponent_width => exponent_width,
denormalize => denormalize,
btype => validfp,
log2i => exp);
if validfp = zero then
return result; -- Result initialized to "0".
elsif validfp = infinity then
result (exponent_width - 1 downto 0) := (others => '1'); -- Exponent all "1"
-- return infinity.
return result;
else
if validfp = denormal then -- Exponent will default to "0".
expon := (others => '0');
frac := arg_real * (2.0 ** (to_integer(expon_base)-1));
else -- Number less than 1. "normal" number
expon := UNSIGNED (to_signed (exp-1, exponent_width));
expon(exponent_width-1) := not expon(exponent_width-1);
frac := (arg_real / 2.0 ** exp) - 1.0; -- Number less than 1.
end if;
for i in 0 to fract'high loop
if frac >= 2.0 ** (-1 - i) then
fract (fract'high - i) := '1';
frac := frac - 2.0 ** (-1 - i);
else
fract (fract'high - i) := '0';
end if;
end loop;
round := false;
case round_style is
when round_nearest =>
if frac > roundfrac or ((frac = roundfrac) and fract(0) = '1') then
round := true;
end if;
when round_inf =>
if frac /= 0.0 and result(exponent_width) = '0' then
round := true;
end if;
when round_neginf =>
if frac /= 0.0 and result(exponent_width) = '1' then
round := true;
end if;
when others =>
null; -- don't round
end case;
if (round) then
if and_reduce (fract) = '1' then -- fraction is all "1"
expon := expon + 1;
fract := (others => '0');
else
fract := fract + 1;
end if;
end if;
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon);
result (-1 downto -fraction_width) := UNRESOLVED_float(fract);
return result;
end if;
end function to_float;
-- to_float (Integer)
function to_float (
arg : INTEGER;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable arg_int : NATURAL; -- Natural version of argument
variable expon : SIGNED (exponent_width-1 downto 0);
variable exptmp : SIGNED (exponent_width-1 downto 0);
-- Unsigned version of exp.
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable fract : UNSIGNED (fraction_width-1 downto 0) := (others => '0');
variable fracttmp : UNSIGNED (fraction_width-1 downto 0);
variable round : BOOLEAN;
variable shift : NATURAL;
variable shiftr : NATURAL;
variable roundfrac : NATURAL; -- used in rounding
begin
if arg < 0 then
result (exponent_width) := '1';
arg_int := -arg; -- Make it positive.
else
result (exponent_width) := '0';
arg_int := arg;
end if;
if arg_int = 0 then
result := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
-- If the number is larger than we can represent in this number system
-- we need to return infinity.
shift := log2(arg_int);
if shift > to_integer(expon_base) then
-- worry about infinity
if result (exponent_width) = '0' then
result := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
-- return negative infinity.
result := neg_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
end if;
else -- Normal number (can't be denormal)
-- Compute Exponent
expon := to_signed (shift-1, expon'length); -- positive fraction.
-- Compute Fraction
arg_int := arg_int - 2**shift; -- Subtract off the 1.0
shiftr := shift;
for I in fract'high downto maximum (fract'high - shift + 1, 0) loop
shiftr := shiftr - 1;
if (arg_int >= 2**shiftr) then
arg_int := arg_int - 2**shiftr;
fract(I) := '1';
else
fract(I) := '0';
end if;
end loop;
-- Rounding routine
round := false;
if arg_int > 0 then
roundfrac := 2**(shiftr-1);
case round_style is
when round_nearest =>
if arg_int > roundfrac or
((arg_int = roundfrac) and fract(0) = '1') then
round := true;
end if;
when round_inf =>
if arg_int /= 0 and result (exponent_width) = '0' then
round := true;
end if;
when round_neginf =>
if arg_int /= 0 and result (exponent_width) = '1' then
round := true;
end if;
when others =>
null;
end case;
end if;
if round then
fp_round(fract_in => fract,
expon_in => expon,
fract_out => fracttmp,
expon_out => exptmp);
fract := fracttmp;
expon := exptmp;
end if;
-- Put the number together and return
expon(exponent_width-1) := not expon(exponent_width-1);
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon);
result (-1 downto -fraction_width) := UNRESOLVED_float(fract);
end if;
end if;
return result;
end function to_float;
-- to_float (unsigned)
function to_float (
arg : UNSIGNED;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
constant ARG_LEFT : INTEGER := ARG'length-1;
alias XARG : UNSIGNED(ARG_LEFT downto 0) is ARG;
variable arg_int : UNSIGNED(xarg'range); -- Real version of argument
variable argb2 : UNSIGNED(xarg'high/2 downto 0); -- log2 of input
variable rexp : SIGNED (exponent_width - 1 downto 0);
variable exp : SIGNED (exponent_width - 1 downto 0);
-- signed version of exp.
variable expon : UNSIGNED (exponent_width - 1 downto 0);
-- Unsigned version of exp.
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable round : BOOLEAN;
variable fract : UNSIGNED (fraction_width-1 downto 0);
variable rfract : UNSIGNED (fraction_width-1 downto 0);
begin
arg_int := UNSIGNED(to_x01(STD_LOGIC_VECTOR (xarg)));
if Is_X (arg_int) then
result := (others => 'X');
elsif (arg_int = 0) then
result := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
else -- Normal number (can't be denormal)
result (exponent_width) := '0'; -- positive sign
-- Compute Exponent
argb2 := to_unsigned(find_leftmost(arg_int, '1'), argb2'length); -- Log2
if argb2 > UNSIGNED(expon_base) then
result := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
exp := SIGNED(resize(argb2, exp'length));
arg_int := shift_left (arg_int, arg_int'high-to_integer(exp));
if (arg_int'high > fraction_width) then
fract := arg_int (arg_int'high-1 downto (arg_int'high-fraction_width));
round := check_round (
fract_in => fract (0),
sign => '0',
remainder => arg_int((arg_int'high-fraction_width-1)
downto 0),
round_style => round_style);
if round then
fp_round(fract_in => fract,
expon_in => exp,
fract_out => rfract,
expon_out => rexp);
else
rfract := fract;
rexp := exp;
end if;
else
rexp := exp;
rfract := (others => '0');
rfract (fraction_width-1 downto fraction_width-1-(arg_int'high-1)) :=
arg_int (arg_int'high-1 downto 0);
end if;
expon := UNSIGNED (rexp-1);
expon(exponent_width-1) := not expon(exponent_width-1);
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon);
result (-1 downto -fraction_width) := UNRESOLVED_float(rfract);
end if;
end if;
return result;
end function to_float;
-- to_float (signed)
function to_float (
arg : SIGNED;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
constant ARG_LEFT : INTEGER := ARG'length-1;
alias XARG : SIGNED(ARG_LEFT downto 0) is ARG;
variable arg_int : UNSIGNED(xarg'range); -- Real version of argument
variable argb2 : UNSIGNED(xarg'high/2 downto 0); -- log2 of input
variable rexp : SIGNED (exponent_width - 1 downto 0);
variable exp : SIGNED (exponent_width - 1 downto 0);
-- signed version of exp.
variable expon : UNSIGNED (exponent_width - 1 downto 0);
-- Unsigned version of exp.
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable round : BOOLEAN;
variable fract : UNSIGNED (fraction_width-1 downto 0);
variable rfract : UNSIGNED (fraction_width-1 downto 0);
begin
if Is_X (xarg) then
result := (others => 'X');
elsif (xarg = 0) then
result := zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
else -- Normal number (can't be denormal)
result (exponent_width) := to_X01(xarg (xarg'high));
arg_int := UNSIGNED(abs (to_01(xarg)));
-- Compute Exponent
argb2 := to_unsigned(find_leftmost(arg_int, '1'), argb2'length); -- Log2
if argb2 > UNSIGNED(expon_base) then
result := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
exp := SIGNED(resize(argb2, exp'length));
arg_int := shift_left (arg_int, arg_int'high-to_integer(exp));
if (arg_int'high > fraction_width) then
fract := arg_int (arg_int'high-1 downto (arg_int'high-fraction_width));
round := check_round (
fract_in => fract (0),
sign => result (exponent_width),
remainder => arg_int((arg_int'high-fraction_width-1)
downto 0),
round_style => round_style);
if round then
fp_round(fract_in => fract,
expon_in => exp,
fract_out => rfract,
expon_out => rexp);
else
rfract := fract;
rexp := exp;
end if;
else
rexp := exp;
rfract := (others => '0');
rfract (fraction_width-1 downto fraction_width-1-(arg_int'high-1)) :=
arg_int (arg_int'high-1 downto 0);
end if;
expon := UNSIGNED (rexp-1);
expon(exponent_width-1) := not expon(exponent_width-1);
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon);
result (-1 downto -fraction_width) := UNRESOLVED_float(rfract);
end if;
end if;
return result;
end function to_float;
-- std_logic_vector to float
function to_float (
arg : STD_ULOGIC_VECTOR;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width) -- length of FP output fraction
return UNRESOLVED_float is
variable fpvar : UNRESOLVED_float (exponent_width downto -fraction_width);
begin
fpvar := UNRESOLVED_float(arg);
return fpvar;
end function to_float;
-- purpose: converts a ufixed to a floating point
function to_float (
arg : UNRESOLVED_ufixed; -- unsigned fixed point input
constant exponent_width : NATURAL := float_exponent_width; -- width of exponent
constant fraction_width : NATURAL := float_fraction_width; -- width of fraction
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- use ieee extensions
return UNRESOLVED_float is
constant integer_width : INTEGER := arg'high;
constant in_fraction_width : INTEGER := arg'low;
variable xresult : ufixed (integer_width downto in_fraction_width);
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable arg_int : UNSIGNED (integer_width - in_fraction_width downto 0);
variable exp, exptmp : SIGNED (exponent_width downto 0);
variable expon : UNSIGNED (exponent_width - 1 downto 0); -- Unsigned version of exp.
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable fract, fracttmp : UNSIGNED (fraction_width-1 downto 0) :=
(others => '0');
variable round : BOOLEAN := false;
begin -- function to_float
xresult := to_01(arg, 'X');
arg_int := UNSIGNED(to_slv(xresult));
if Is_X (arg_int) then
result := (others => 'X');
elsif (arg_int = 0) then
result := (others => '0'); -- return zero
else
result := (others => '0'); -- positive sign
-- Compute Exponent
exp := to_signed(find_leftmost(arg_int, '1'), exp'length); -- Log2
if exp + in_fraction_width > expon_base then -- return infinity
result := pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
return result;
elsif (denormalize and
(exp + in_fraction_width <= -resize(expon_base, exp'length))) then
-- denormal number
exp := -resize(expon_base, exp'length);
-- shift by a constant
arg_int := shift_left (arg_int,
(arg_int'high + to_integer(expon_base)
+ in_fraction_width - 1));
if (arg_int'high > fraction_width) then
fract := arg_int (arg_int'high-1 downto (arg_int'high-fraction_width));
round := check_round (
fract_in => arg_int(arg_int'high-fraction_width),
sign => '0',
remainder => arg_int((arg_int'high-fraction_width-1)
downto 0),
round_style => round_style);
if (round) then
fp_round (fract_in => arg_int (arg_int'high-1 downto
(arg_int'high-fraction_width)),
expon_in => exp,
fract_out => fract,
expon_out => exptmp);
exp := exptmp;
end if;
else
fract (fraction_width-1 downto fraction_width-1-(arg_int'high-1)) :=
arg_int (arg_int'high-1 downto 0);
end if;
else
arg_int := shift_left (arg_int, arg_int'high-to_integer(exp));
exp := exp + in_fraction_width;
if (arg_int'high > fraction_width) then
fract := arg_int (arg_int'high-1 downto (arg_int'high-fraction_width));
round := check_round (
fract_in => fract(0),
sign => '0',
remainder => arg_int((arg_int'high-fraction_width-1)
downto 0),
round_style => round_style);
if (round) then
fp_round (fract_in => fract,
expon_in => exp,
fract_out => fracttmp,
expon_out => exptmp);
fract := fracttmp;
exp := exptmp;
end if;
else
fract (fraction_width-1 downto fraction_width-1-(arg_int'high-1)) :=
arg_int (arg_int'high-1 downto 0);
end if;
end if;
expon := UNSIGNED (resize (exp-1, exponent_width));
expon(exponent_width-1) := not expon(exponent_width-1);
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon);
result (-1 downto -fraction_width) := UNRESOLVED_float(fract);
end if;
return result;
end function to_float;
function to_float (
arg : UNRESOLVED_sfixed; -- signed fixed point
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width; -- length of FP output fraction
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- rounding option
return UNRESOLVED_float is
constant integer_width : INTEGER := arg'high;
constant in_fraction_width : INTEGER := arg'low;
variable xresult : sfixed (integer_width downto in_fraction_width);
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable arg_int : UNSIGNED(integer_width - in_fraction_width - 1
downto 0); -- signed version of argument
variable argx : SIGNED (integer_width - in_fraction_width downto 0);
variable exp, exptmp : SIGNED (exponent_width downto 0);
variable expon : UNSIGNED (exponent_width - 1 downto 0);
-- Unsigned version of exp.
constant expon_base : SIGNED (exponent_width-1 downto 0) :=
gen_expon_base(exponent_width); -- exponent offset
variable fract, fracttmp : UNSIGNED (fraction_width-1 downto 0) :=
(others => '0');
variable round : BOOLEAN := false;
begin
xresult := to_01(arg, 'X');
argx := SIGNED(to_slv(xresult));
if (or_reduce (UNSIGNED(argx)) = 'X') then
result := (others => 'X');
elsif (argx = 0) then
result := (others => '0');
else
result := (others => '0'); -- zero out the result
if argx(argx'left) = '1' then -- toss the sign bit
result (exponent_width) := '1'; -- Negative number
argx := -argx; -- Make it positive.
else
result (exponent_width) := '0';
end if;
arg_int := UNSIGNED(to_x01(STD_LOGIC_VECTOR (argx(arg_int'range))));
-- Compute Exponent
exp := to_signed(find_leftmost(arg_int, '1'), exp'length); -- Log2
if exp + in_fraction_width > expon_base then -- return infinity
result (-1 downto -fraction_width) := (others => '0');
result (exponent_width -1 downto 0) := (others => '1');
return result;
elsif (denormalize and
(exp + in_fraction_width <= -resize(expon_base, exp'length))) then
exp := -resize(expon_base, exp'length);
-- shift by a constant
arg_int := shift_left (arg_int,
(arg_int'high + to_integer(expon_base)
+ in_fraction_width - 1));
if (arg_int'high > fraction_width) then
fract := arg_int (arg_int'high-1 downto (arg_int'high-fraction_width));
round := check_round (
fract_in => arg_int(arg_int'high-fraction_width),
sign => result(result'high),
remainder => arg_int((arg_int'high-fraction_width-1)
downto 0),
round_style => round_style);
if (round) then
fp_round (fract_in => arg_int (arg_int'high-1 downto
(arg_int'high-fraction_width)),
expon_in => exp,
fract_out => fract,
expon_out => exptmp);
exp := exptmp;
end if;
else
fract (fraction_width-1 downto fraction_width-1-(arg_int'high-1)) :=
arg_int (arg_int'high-1 downto 0);
end if;
else
arg_int := shift_left (arg_int, arg_int'high-to_integer(exp));
exp := exp + in_fraction_width;
if (arg_int'high > fraction_width) then
fract := arg_int (arg_int'high-1 downto (arg_int'high-fraction_width));
round := check_round (
fract_in => fract(0),
sign => result(result'high),
remainder => arg_int((arg_int'high-fraction_width-1)
downto 0),
round_style => round_style);
if (round) then
fp_round (fract_in => fract,
expon_in => exp,
fract_out => fracttmp,
expon_out => exptmp);
fract := fracttmp;
exp := exptmp;
end if;
else
fract (fraction_width-1 downto fraction_width-1-(arg_int'high-1)) :=
arg_int (arg_int'high-1 downto 0);
end if;
end if;
expon := UNSIGNED (resize(exp-1, exponent_width));
expon(exponent_width-1) := not expon(exponent_width-1);
result (exponent_width-1 downto 0) := UNRESOLVED_float(expon);
result (-1 downto -fraction_width) := UNRESOLVED_float(fract);
end if;
return result;
end function to_float;
-- size_res functions
-- Integer to float
function to_float (
arg : INTEGER;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style);
return result;
end if;
end function to_float;
-- real to float
function to_float (
arg : REAL;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding option
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style,
denormalize => denormalize);
return result;
end if;
end function to_float;
-- unsigned to float
function to_float (
arg : UNSIGNED;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style) -- rounding option
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style);
return result;
end if;
end function to_float;
-- signed to float
function to_float (
arg : SIGNED;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style) -- rounding
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style);
return result;
end if;
end function to_float;
-- std_ulogic_vector to float
function to_float (
arg : STD_ULOGIC_VECTOR;
size_res : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low);
return result;
end if;
end function to_float;
-- unsigned fixed point to float
function to_float (
arg : UNRESOLVED_ufixed; -- unsigned fixed point input
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- use ieee extensions
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style,
denormalize => denormalize);
return result;
end if;
end function to_float;
-- signed fixed point to float
function to_float (
arg : UNRESOLVED_sfixed;
size_res : UNRESOLVED_float;
constant round_style : round_type := float_round_style; -- rounding
constant denormalize : BOOLEAN := float_denormalize) -- rounding option
return UNRESOLVED_float is
variable result : UNRESOLVED_float (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_float (arg => arg,
exponent_width => size_res'high,
fraction_width => -size_res'low,
round_style => round_style,
denormalize => denormalize);
return result;
end if;
end function to_float;
-- to_integer (float)
function to_integer (
arg : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return INTEGER is
variable validfp : valid_fpstate; -- Valid FP state
variable frac : UNSIGNED (-arg'low downto 0); -- Fraction
variable fract : UNSIGNED (1-arg'low downto 0); -- Fraction
variable expon : SIGNED (arg'high-1 downto 0);
variable isign : STD_ULOGIC; -- internal version of sign
variable round : STD_ULOGIC; -- is rounding needed?
variable result : INTEGER;
variable base : INTEGER; -- Integer exponent
begin
validfp := classfp (arg, check_error);
classcase : case validfp is
when isx | nan | quiet_nan | pos_zero | neg_zero | pos_denormal | neg_denormal =>
result := 0; -- return 0
when pos_inf =>
result := INTEGER'high;
when neg_inf =>
result := INTEGER'low;
when others =>
break_number (
arg => arg,
fptyp => validfp,
denormalize => false,
fract => frac,
expon => expon);
fract (fract'high) := '0'; -- Add extra bit for 0.6 case
fract (fract'high-1 downto 0) := frac;
isign := to_x01 (arg (arg'high));
base := to_integer (expon) + 1;
if base < -1 then
result := 0;
elsif base >= frac'high then
result := to_integer (fract) * 2**(base - frac'high);
else -- We need to round
if base = -1 then -- trap for 0.6 case.
result := 0;
else
result := to_integer (fract (frac'high downto frac'high-base));
end if;
-- rounding routine
case round_style is
when round_nearest =>
if frac'high - base > 1 then
round := fract (frac'high - base - 1) and
(fract (frac'high - base)
or (or_reduce (fract (frac'high - base - 2 downto 0))));
else
round := fract (frac'high - base - 1) and
fract (frac'high - base);
end if;
when round_inf =>
round := fract(frac'high - base - 1) and not isign;
when round_neginf =>
round := fract(frac'high - base - 1) and isign;
when others =>
round := '0';
end case;
if round = '1' then
result := result + 1;
end if;
end if;
if isign = '1' then
result := - result;
end if;
end case classcase;
return result;
end function to_integer;
-- to_unsigned (float)
function to_unsigned (
arg : UNRESOLVED_float; -- floating point input
constant size : NATURAL; -- length of output
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return UNSIGNED is
variable validfp : valid_fpstate; -- Valid FP state
variable frac : UNSIGNED (size-1 downto 0); -- Fraction
variable sign : STD_ULOGIC; -- not used
begin
validfp := classfp (arg, check_error);
classcase : case validfp is
when isx | nan | quiet_nan =>
frac := (others => 'X');
when pos_zero | neg_inf | neg_zero | neg_normal | pos_denormal | neg_denormal =>
frac := (others => '0'); -- return 0
when pos_inf =>
frac := (others => '1');
when others =>
float_to_unsigned (
arg => arg,
frac => frac,
sign => sign,
denormalize => false,
bias => 0,
round_style => round_style);
end case classcase;
return (frac);
end function to_unsigned;
-- to_signed (float)
function to_signed (
arg : UNRESOLVED_float; -- floating point input
constant size : NATURAL; -- length of output
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return SIGNED is
variable sign : STD_ULOGIC; -- true if negative
variable validfp : valid_fpstate; -- Valid FP state
variable frac : UNSIGNED (size-1 downto 0); -- Fraction
variable result : SIGNED (size-1 downto 0);
begin
validfp := classfp (arg, check_error);
classcase : case validfp is
when isx | nan | quiet_nan =>
result := (others => 'X');
when pos_zero | neg_zero | pos_denormal | neg_denormal =>
result := (others => '0'); -- return 0
when pos_inf =>
result := (others => '1');
result (result'high) := '0';
when neg_inf =>
result := (others => '0');
result (result'high) := '1';
when others =>
float_to_unsigned (
arg => arg,
sign => sign,
frac => frac,
denormalize => false,
bias => 0,
round_style => round_style);
result (size-1) := '0';
result (size-2 downto 0) := SIGNED(frac (size-2 downto 0));
if sign = '1' then
-- Because the most negative signed number is 1 less than the most
-- positive signed number, we need this code.
if frac(frac'high) = '1' then -- return most negative number
result := (others => '0');
result (result'high) := '1';
else
result := -result;
end if;
else
if frac(frac'high) = '1' then -- return most positive number
result := (others => '1');
result (result'high) := '0';
end if;
end if;
end case classcase;
return result;
end function to_signed;
-- purpose: Converts a float to ufixed
function to_ufixed (
arg : UNRESOLVED_float; -- fp input
constant left_index : INTEGER; -- integer part
constant right_index : INTEGER; -- fraction part
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_ufixed is
constant fraction_width : INTEGER := -mine(arg'low, arg'low); -- length of FP output fraction
constant exponent_width : INTEGER := arg'high; -- length of FP output exponent
constant size : INTEGER := left_index - right_index + 4; -- unsigned size
variable expon_base : INTEGER; -- exponent offset
variable validfp : valid_fpstate; -- Valid FP state
variable exp : INTEGER; -- Exponent
variable expon : UNSIGNED (exponent_width-1 downto 0); -- Vectorized exponent
-- Base to divide fraction by
variable frac : UNSIGNED (size-1 downto 0) := (others => '0'); -- Fraction
variable frac_shift : UNSIGNED (size-1 downto 0); -- Fraction shifted
variable shift : INTEGER;
variable result_big : UNRESOLVED_ufixed (left_index downto right_index-3);
variable result : UNRESOLVED_ufixed (left_index downto right_index); -- result
begin -- function to_ufixed
validfp := classfp (arg, check_error);
classcase : case validfp is
when isx | nan | quiet_nan =>
frac := (others => 'X');
when pos_zero | neg_inf | neg_zero | neg_normal | neg_denormal =>
frac := (others => '0'); -- return 0
when pos_inf =>
frac := (others => '1'); -- always saturate
when others =>
expon_base := 2**(exponent_width-1) -1; -- exponent offset
-- Figure out the fraction
if (validfp = pos_denormal) and denormalize then
exp := -expon_base +1;
frac (frac'high) := '0'; -- Remove the "1.0".
else
-- exponent /= '0', normal floating point
expon := UNSIGNED(arg (exponent_width-1 downto 0));
expon(exponent_width-1) := not expon(exponent_width-1);
exp := to_integer (SIGNED(expon)) +1;
frac (frac'high) := '1'; -- Add the "1.0".
end if;
shift := (frac'high - 3 + right_index) - exp;
if fraction_width > frac'high then -- Can only use size-2 bits
frac (frac'high-1 downto 0) := UNSIGNED (to_slv (arg(-1 downto
-frac'high)));
else -- can use all bits
frac (frac'high-1 downto frac'high-fraction_width) :=
UNSIGNED (to_slv (arg(-1 downto -fraction_width)));
end if;
frac_shift := frac srl shift;
if shift < 0 then -- Overflow
frac := (others => '1');
else
frac := frac_shift;
end if;
end case classcase;
result_big := to_ufixed (
arg => STD_ULOGIC_VECTOR(frac),
left_index => left_index,
right_index => (right_index-3));
result := resize (arg => result_big,
left_index => left_index,
right_index => right_index,
round_style => round_style,
overflow_style => overflow_style);
return result;
end function to_ufixed;
-- purpose: Converts a float to sfixed
function to_sfixed (
arg : UNRESOLVED_float; -- fp input
constant left_index : INTEGER; -- integer part
constant right_index : INTEGER; -- fraction part
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_sfixed is
constant fraction_width : INTEGER := -mine(arg'low, arg'low); -- length of FP output fraction
constant exponent_width : INTEGER := arg'high; -- length of FP output exponent
constant size : INTEGER := left_index - right_index + 4; -- unsigned size
variable expon_base : INTEGER; -- exponent offset
variable validfp : valid_fpstate; -- Valid FP state
variable exp : INTEGER; -- Exponent
variable sign : BOOLEAN; -- true if negative
variable expon : UNSIGNED (exponent_width-1 downto 0); -- Vectorized exponent
-- Base to divide fraction by
variable frac : UNSIGNED (size-2 downto 0) := (others => '0'); -- Fraction
variable frac_shift : UNSIGNED (size-2 downto 0); -- Fraction shifted
variable shift : INTEGER;
variable rsigned : SIGNED (size-1 downto 0); -- signed version of result
variable result_big : UNRESOLVED_sfixed (left_index downto right_index-3);
variable result : UNRESOLVED_sfixed (left_index downto right_index)
:= (others => '0'); -- result
begin -- function to_ufixed
validfp := classfp (arg, check_error);
classcase : case validfp is
when isx | nan | quiet_nan =>
result := (others => 'X');
when pos_zero | neg_zero =>
result := (others => '0'); -- return 0
when neg_inf =>
result (left_index) := '1'; -- return smallest negative number
when pos_inf =>
result := (others => '1'); -- return largest number
result (left_index) := '0';
when others =>
expon_base := 2**(exponent_width-1) -1; -- exponent offset
if arg(exponent_width) = '0' then
sign := false;
else
sign := true;
end if;
-- Figure out the fraction
if (validfp = pos_denormal or validfp = neg_denormal)
and denormalize then
exp := -expon_base +1;
frac (frac'high) := '0'; -- Add the "1.0".
else
-- exponent /= '0', normal floating point
expon := UNSIGNED(arg (exponent_width-1 downto 0));
expon(exponent_width-1) := not expon(exponent_width-1);
exp := to_integer (SIGNED(expon)) +1;
frac (frac'high) := '1'; -- Add the "1.0".
end if;
shift := (frac'high - 3 + right_index) - exp;
if fraction_width > frac'high then -- Can only use size-2 bits
frac (frac'high-1 downto 0) := UNSIGNED (to_slv (arg(-1 downto
-frac'high)));
else -- can use all bits
frac (frac'high-1 downto frac'high-fraction_width) :=
UNSIGNED (to_slv (arg(-1 downto -fraction_width)));
end if;
frac_shift := frac srl shift;
if shift < 0 then -- Overflow
frac := (others => '1');
else
frac := frac_shift;
end if;
if not sign then
rsigned := SIGNED("0" & frac);
else
rsigned := -(SIGNED("0" & frac));
end if;
result_big := to_sfixed (
arg => STD_LOGIC_VECTOR(rsigned),
left_index => left_index,
right_index => (right_index-3));
result := resize (arg => result_big,
left_index => left_index,
right_index => right_index,
round_style => round_style,
overflow_style => overflow_style);
end case classcase;
return result;
end function to_sfixed;
-- size_res versions
-- float to unsigned
function to_unsigned (
arg : UNRESOLVED_float; -- floating point input
size_res : UNSIGNED;
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return UNSIGNED is
variable result : UNSIGNED (size_res'range);
begin
if (SIZE_RES'length = 0) then
return result;
else
result := to_unsigned (
arg => arg,
size => size_res'length,
check_error => check_error,
round_style => round_style);
return result;
end if;
end function to_unsigned;
-- float to signed
function to_signed (
arg : UNRESOLVED_float; -- floating point input
size_res : SIGNED;
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant round_style : round_type := float_round_style) -- rounding option
return SIGNED is
variable result : SIGNED (size_res'range);
begin
if (SIZE_RES'length = 0) then
return result;
else
result := to_signed (
arg => arg,
size => size_res'length,
check_error => check_error,
round_style => round_style);
return result;
end if;
end function to_signed;
-- purpose: Converts a float to unsigned fixed point
function to_ufixed (
arg : UNRESOLVED_float; -- fp input
size_res : UNRESOLVED_ufixed;
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_ufixed is
variable result : UNRESOLVED_ufixed (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_ufixed (
arg => arg,
left_index => size_res'high,
right_index => size_res'low,
round_style => round_style,
overflow_style => overflow_style,
check_error => check_error,
denormalize => denormalize);
return result;
end if;
end function to_ufixed;
-- float to signed fixed point
function to_sfixed (
arg : UNRESOLVED_float; -- fp input
size_res : UNRESOLVED_sfixed;
constant round_style : fixed_round_style_type := fixed_round_style; -- rounding
constant overflow_style : fixed_overflow_style_type := fixed_overflow_style; -- saturate
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_sfixed is
variable result : UNRESOLVED_sfixed (size_res'left downto size_res'right);
begin
if (result'length < 1) then
return result;
else
result := to_sfixed (
arg => arg,
left_index => size_res'high,
right_index => size_res'low,
round_style => round_style,
overflow_style => overflow_style,
check_error => check_error,
denormalize => denormalize);
return result;
end if;
end function to_sfixed;
-- to_real (float)
-- typically not Synthesizable unless the input is a constant.
function to_real (
arg : UNRESOLVED_float; -- floating point input
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return REAL is
constant fraction_width : INTEGER := -mine(arg'low, arg'low); -- length of FP output fraction
constant exponent_width : INTEGER := arg'high; -- length of FP output exponent
variable sign : REAL; -- Sign, + or - 1
variable exp : INTEGER; -- Exponent
variable expon_base : INTEGER; -- exponent offset
variable frac : REAL := 0.0; -- Fraction
variable validfp : valid_fpstate; -- Valid FP state
variable expon : UNSIGNED (exponent_width - 1 downto 0)
:= (others => '1'); -- Vectorized exponent
begin
validfp := classfp (arg, check_error);
classcase : case validfp is
when isx | pos_zero | neg_zero | nan | quiet_nan =>
return 0.0;
when neg_inf =>
return REAL'low; -- Negative infinity.
when pos_inf =>
return REAL'high; -- Positive infinity
when others =>
expon_base := 2**(exponent_width-1) -1;
if to_X01(arg(exponent_width)) = '0' then
sign := 1.0;
else
sign := -1.0;
end if;
-- Figure out the fraction
for i in 0 to fraction_width-1 loop
if to_X01(arg (-1 - i)) = '1' then
frac := frac + (2.0 **(-1 - i));
end if;
end loop; -- i
if validfp = pos_normal or validfp = neg_normal or not denormalize then
-- exponent /= '0', normal floating point
expon := UNSIGNED(arg (exponent_width-1 downto 0));
expon(exponent_width-1) := not expon(exponent_width-1);
exp := to_integer (SIGNED(expon)) +1;
sign := sign * (2.0 ** exp) * (1.0 + frac);
else -- exponent = '0', IEEE extended floating point
exp := 1 - expon_base;
sign := sign * (2.0 ** exp) * frac;
end if;
return sign;
end case classcase;
end function to_real;
-- purpose: Removes meta-logical values from FP string
function to_01 (
arg : UNRESOLVED_float; -- floating point input
XMAP : STD_LOGIC := '0')
return UNRESOLVED_float is
variable result : UNRESOLVED_float (arg'range);
begin -- function to_01
if (arg'length < 1) then
assert NO_WARNING
report float_pkg'instance_name
& "TO_01: null detected, returning NULL"
severity warning;
return NAFP;
end if;
result := UNRESOLVED_float (STD_LOGIC_VECTOR(to_01(UNSIGNED(to_slv(arg)), XMAP)));
return result;
end function to_01;
function Is_X
(arg : UNRESOLVED_float)
return BOOLEAN is
begin
return Is_X (to_slv(arg));
end function Is_X;
function to_X01 (arg : UNRESOLVED_float) return UNRESOLVED_float is
variable result : UNRESOLVED_float (arg'range);
begin
if (arg'length < 1) then
assert NO_WARNING
report float_pkg'instance_name
& "TO_X01: null detected, returning NULL"
severity warning;
return NAFP;
else
result := UNRESOLVED_float (to_X01(to_slv(arg)));
return result;
end if;
end function to_X01;
function to_X01Z (arg : UNRESOLVED_float) return UNRESOLVED_float is
variable result : UNRESOLVED_float (arg'range);
begin
if (arg'length < 1) then
assert NO_WARNING
report float_pkg'instance_name
& "TO_X01Z: null detected, returning NULL"
severity warning;
return NAFP;
else
result := UNRESOLVED_float (to_X01Z(to_slv(arg)));
return result;
end if;
end function to_X01Z;
function to_UX01 (arg : UNRESOLVED_float) return UNRESOLVED_float is
variable result : UNRESOLVED_float (arg'range);
begin
if (arg'length < 1) then
assert NO_WARNING
report float_pkg'instance_name
& "TO_UX01: null detected, returning NULL"
severity warning;
return NAFP;
else
result := UNRESOLVED_float (to_UX01(to_slv(arg)));
return result;
end if;
end function to_UX01;
-- These allows the base math functions to use the default values
-- of their parameters. Thus they do full IEEE floating point.
function "+" (l, r : UNRESOLVED_float) return UNRESOLVED_float is
begin
return add (l, r);
end function "+";
function "-" (l, r : UNRESOLVED_float) return UNRESOLVED_float is
begin
return subtract (l, r);
end function "-";
function "*" (l, r : UNRESOLVED_float) return UNRESOLVED_float is
begin
return multiply (l, r);
end function "*";
function "/" (l, r : UNRESOLVED_float) return UNRESOLVED_float is
begin
return divide (l, r);
end function "/";
function "rem" (l, r : UNRESOLVED_float) return UNRESOLVED_float is
begin
return remainder (l, r);
end function "rem";
function "mod" (l, r : UNRESOLVED_float) return UNRESOLVED_float is
begin
return modulo (l, r);
end function "mod";
-- overloaded versions
function "+" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return add (l, r_float);
end function "+";
function "+" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return add (l_float, r);
end function "+";
function "+" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return add (l, r_float);
end function "+";
function "+" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return add (l_float, r);
end function "+";
function "-" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return subtract (l, r_float);
end function "-";
function "-" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return subtract (l_float, r);
end function "-";
function "-" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return subtract (l, r_float);
end function "-";
function "-" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return subtract (l_float, r);
end function "-";
function "*" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return multiply (l, r_float);
end function "*";
function "*" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return multiply (l_float, r);
end function "*";
function "*" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return multiply (l, r_float);
end function "*";
function "*" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return multiply (l_float, r);
end function "*";
function "/" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return divide (l, r_float);
end function "/";
function "/" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return divide (l_float, r);
end function "/";
function "/" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return divide (l, r_float);
end function "/";
function "/" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return divide (l_float, r);
end function "/";
function "rem" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return remainder (l, r_float);
end function "rem";
function "rem" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return remainder (l_float, r);
end function "rem";
function "rem" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return remainder (l, r_float);
end function "rem";
function "rem" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return remainder (l_float, r);
end function "rem";
function "mod" (l : UNRESOLVED_float; r : REAL) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return modulo (l, r_float);
end function "mod";
function "mod" (l : REAL; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return modulo (l_float, r);
end function "mod";
function "mod" (l : UNRESOLVED_float; r : INTEGER) return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return modulo (l, r_float);
end function "mod";
function "mod" (l : INTEGER; r : UNRESOLVED_float) return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return modulo (l_float, r);
end function "mod";
function "=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return eq (l, r_float);
end function "=";
function "/=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return ne (l, r_float);
end function "/=";
function ">=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return ge (l, r_float);
end function ">=";
function "<=" (l : UNRESOLVED_float; r : REAL) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return le (l, r_float);
end function "<=";
function ">" (l : UNRESOLVED_float; r : REAL) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return gt (l, r_float);
end function ">";
function "<" (l : UNRESOLVED_float; r : REAL) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return lt (l, r_float);
end function "<";
function "=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return eq (l_float, r);
end function "=";
function "/=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return ne (l_float, r);
end function "/=";
function ">=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return ge (l_float, r);
end function ">=";
function "<=" (l : REAL; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return le (l_float, r);
end function "<=";
function ">" (l : REAL; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return gt (l_float, r);
end function ">";
function "<" (l : REAL; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return lt (l_float, r);
end function "<";
function "=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return eq (l, r_float);
end function "=";
function "/=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return ne (l, r_float);
end function "/=";
function ">=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return ge (l, r_float);
end function ">=";
function "<=" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return le (l, r_float);
end function "<=";
function ">" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return gt (l, r_float);
end function ">";
function "<" (l : UNRESOLVED_float; r : INTEGER) return BOOLEAN is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return lt (l, r_float);
end function "<";
function "=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return eq (l_float, r);
end function "=";
function "/=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return ne (l_float, r);
end function "/=";
function ">=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return ge (l_float, r);
end function ">=";
function "<=" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return le (l_float, r);
end function "<=";
function ">" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return gt (l_float, r);
end function ">";
function "<" (l : INTEGER; r : UNRESOLVED_float) return BOOLEAN is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float(l, r'high, -r'low);
return lt (l_float, r);
end function "<";
-- ?= overloads
function \?=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?=\ (l, r_float);
end function \?=\;
function \?/=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?/=\ (l, r_float);
end function \?/=\;
function \?>\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?>\ (l, r_float);
end function \?>\;
function \?>=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?>=\ (l, r_float);
end function \?>=\;
function \?<\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?<\ (l, r_float);
end function \?<\;
function \?<=\ (l : UNRESOLVED_float; r : REAL) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?<=\ (l, r_float);
end function \?<=\;
-- real and float
function \?=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?=\ (l_float, r);
end function \?=\;
function \?/=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?/=\ (l_float, r);
end function \?/=\;
function \?>\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?>\ (l_float, r);
end function \?>\;
function \?>=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?>=\ (l_float, r);
end function \?>=\;
function \?<\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?<\ (l_float, r);
end function \?<\;
function \?<=\ (l : REAL; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?<=\ (l_float, r);
end function \?<=\;
-- ?= overloads
function \?=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?=\ (l, r_float);
end function \?=\;
function \?/=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?/=\ (l, r_float);
end function \?/=\;
function \?>\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?>\ (l, r_float);
end function \?>\;
function \?>=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?>=\ (l, r_float);
end function \?>=\;
function \?<\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?<\ (l, r_float);
end function \?<\;
function \?<=\ (l : UNRESOLVED_float; r : INTEGER) return STD_ULOGIC is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return \?<=\ (l, r_float);
end function \?<=\;
-- integer and float
function \?=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?=\ (l_float, r);
end function \?=\;
function \?/=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?/=\ (l_float, r);
end function \?/=\;
function \?>\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?>\ (l_float, r);
end function \?>\;
function \?>=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?>=\ (l_float, r);
end function \?>=\;
function \?<\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?<\ (l_float, r);
end function \?<\;
function \?<=\ (l : INTEGER; r : UNRESOLVED_float) return STD_ULOGIC is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return \?<=\ (l_float, r);
end function \?<=\;
-- minimum and maximum overloads
function minimum (l : UNRESOLVED_float; r : REAL)
return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return minimum (l, r_float);
end function minimum;
function maximum (l : UNRESOLVED_float; r : REAL)
return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return maximum (l, r_float);
end function maximum;
function minimum (l : REAL; r : UNRESOLVED_float)
return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return minimum (l_float, r);
end function minimum;
function maximum (l : REAL; r : UNRESOLVED_float)
return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return maximum (l_float, r);
end function maximum;
function minimum (l : UNRESOLVED_float; r : INTEGER)
return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return minimum (l, r_float);
end function minimum;
function maximum (l : UNRESOLVED_float; r : INTEGER)
return UNRESOLVED_float is
variable r_float : UNRESOLVED_float (l'range);
begin
r_float := to_float (r, l'high, -l'low);
return maximum (l, r_float);
end function maximum;
function minimum (l : INTEGER; r : UNRESOLVED_float)
return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return minimum (l_float, r);
end function minimum;
function maximum (l : INTEGER; r : UNRESOLVED_float)
return UNRESOLVED_float is
variable l_float : UNRESOLVED_float (r'range);
begin
l_float := to_float (l, r'high, -r'low);
return maximum (l_float, r);
end function maximum;
----------------------------------------------------------------------------
-- logical functions
----------------------------------------------------------------------------
function "not" (l : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(l'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (l'range); -- back to float
begin
RESULT := not to_suv(l);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "not";
function "and" (L, R : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(L'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (L'range); -- back to float
begin
RESULT := to_suv(L) and to_suv(R);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "and";
function "or" (L, R : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(L'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (L'range); -- back to float
begin
RESULT := to_suv(L) or to_suv(R);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "or";
function "nand" (L, R : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(L'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (L'range); -- back to float
begin
RESULT := to_suv(L) nand to_suv(R);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "nand";
function "nor" (L, R : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(L'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (L'range); -- back to float
begin
RESULT := to_suv(L) nor to_suv(R);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "nor";
function "xor" (L, R : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(L'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (L'range); -- back to float
begin
RESULT := to_suv(L) xor to_suv(R);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "xor";
function "xnor" (L, R : UNRESOLVED_float) return UNRESOLVED_float is
variable RESULT : STD_ULOGIC_VECTOR(L'length-1 downto 0); -- force downto
variable resfp : UNRESOLVED_float (L'range); -- back to float
begin
RESULT := to_suv(L) xnor to_suv(R);
resfp := UNRESOLVED_float (RESULT);
return resfp;
end function "xnor";
-- Vector and std_ulogic functions, same as functions in numeric_std
function "and" (L : STD_ULOGIC; R : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (R'range);
begin
for i in result'range loop
result(i) := L and R(i);
end loop;
return result;
end function "and";
function "and" (L : UNRESOLVED_float; R : STD_ULOGIC)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (L'range);
begin
for i in result'range loop
result(i) := L(i) and R;
end loop;
return result;
end function "and";
function "or" (L : STD_ULOGIC; R : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (R'range);
begin
for i in result'range loop
result(i) := L or R(i);
end loop;
return result;
end function "or";
function "or" (L : UNRESOLVED_float; R : STD_ULOGIC)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (L'range);
begin
for i in result'range loop
result(i) := L(i) or R;
end loop;
return result;
end function "or";
function "nand" (L : STD_ULOGIC; R : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (R'range);
begin
for i in result'range loop
result(i) := L nand R(i);
end loop;
return result;
end function "nand";
function "nand" (L : UNRESOLVED_float; R : STD_ULOGIC)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (L'range);
begin
for i in result'range loop
result(i) := L(i) nand R;
end loop;
return result;
end function "nand";
function "nor" (L : STD_ULOGIC; R : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (R'range);
begin
for i in result'range loop
result(i) := L nor R(i);
end loop;
return result;
end function "nor";
function "nor" (L : UNRESOLVED_float; R : STD_ULOGIC)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (L'range);
begin
for i in result'range loop
result(i) := L(i) nor R;
end loop;
return result;
end function "nor";
function "xor" (L : STD_ULOGIC; R : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (R'range);
begin
for i in result'range loop
result(i) := L xor R(i);
end loop;
return result;
end function "xor";
function "xor" (L : UNRESOLVED_float; R : STD_ULOGIC)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (L'range);
begin
for i in result'range loop
result(i) := L(i) xor R;
end loop;
return result;
end function "xor";
function "xnor" (L : STD_ULOGIC; R : UNRESOLVED_float)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (R'range);
begin
for i in result'range loop
result(i) := L xnor R(i);
end loop;
return result;
end function "xnor";
function "xnor" (L : UNRESOLVED_float; R : STD_ULOGIC)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (L'range);
begin
for i in result'range loop
result(i) := L(i) xnor R;
end loop;
return result;
end function "xnor";
-- Reduction operator_reduces, same as numeric_std functions
function and_reduce (l : UNRESOLVED_float) return STD_ULOGIC is
begin
return and_reduce (to_suv(l));
end function and_reduce;
function nand_reduce (l : UNRESOLVED_float) return STD_ULOGIC is
begin
return nand_reduce (to_suv(l));
end function nand_reduce;
function or_reduce (l : UNRESOLVED_float) return STD_ULOGIC is
begin
return or_reduce (to_suv(l));
end function or_reduce;
function nor_reduce (l : UNRESOLVED_float) return STD_ULOGIC is
begin
return nor_reduce (to_suv(l));
end function nor_reduce;
function xor_reduce (l : UNRESOLVED_float) return STD_ULOGIC is
begin
return xor_reduce (to_suv(l));
end function xor_reduce;
function xnor_reduce (l : UNRESOLVED_float) return STD_ULOGIC is
begin
return xnor_reduce (to_suv(l));
end function xnor_reduce;
-----------------------------------------------------------------------------
-- Recommended Functions from the IEEE 754 Appendix
-----------------------------------------------------------------------------
-- returns x with the sign of y.
function Copysign (
x, y : UNRESOLVED_float) -- floating point input
return UNRESOLVED_float is
begin
return y(y'high) & x (x'high-1 downto x'low);
end function Copysign;
-- Returns y * 2**n for integral values of N without computing 2**n
function Scalb (
y : UNRESOLVED_float; -- floating point input
N : INTEGER; -- exponent to add
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(y'low, y'low); -- length of FP output fraction
constant exponent_width : NATURAL := y'high; -- length of FP output exponent
variable arg, result : UNRESOLVED_float (exponent_width downto -fraction_width); -- internal argument
variable expon : SIGNED (exponent_width-1 downto 0); -- Vectorized exp
variable exp : SIGNED (exponent_width downto 0);
variable ufract : UNSIGNED (fraction_width downto 0);
constant expon_base : SIGNED (exponent_width-1 downto 0)
:= gen_expon_base(exponent_width); -- exponent offset
variable fptype : valid_fpstate;
begin
-- This can be done by simply adding N to the exponent.
arg := to_01 (y, 'X');
fptype := classfp(arg, check_error);
classcase : case fptype is
when isx =>
result := (others => 'X');
when nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
result := qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
when others =>
break_number (
arg => arg,
fptyp => fptype,
denormalize => denormalize,
fract => ufract,
expon => expon);
exp := resize (expon, exp'length) + N;
result := normalize (
fract => ufract,
expon => exp,
sign => to_x01 (arg (arg'high)),
fraction_width => fraction_width,
exponent_width => exponent_width,
round_style => round_style,
denormalize => denormalize,
nguard => 0);
end case classcase;
return result;
end function Scalb;
-- Returns y * 2**n for integral values of N without computing 2**n
function Scalb (
y : UNRESOLVED_float; -- floating point input
N : SIGNED; -- exponent to add
constant round_style : round_type := float_round_style; -- rounding option
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize) -- Use IEEE extended FP
return UNRESOLVED_float is
variable n_int : INTEGER;
begin
n_int := to_integer(N);
return Scalb (y => y,
N => n_int,
round_style => round_style,
check_error => check_error,
denormalize => denormalize);
end function Scalb;
-- returns the unbiased exponent of x
function Logb (
x : UNRESOLVED_float) -- floating point input
return INTEGER is
constant fraction_width : NATURAL := -mine (x'low, x'low); -- length of FP output fraction
constant exponent_width : NATURAL := x'high; -- length of FP output exponent
variable result : INTEGER; -- result
variable arg : UNRESOLVED_float (exponent_width downto -fraction_width); -- internal argument
variable expon : SIGNED (exponent_width - 1 downto 0);
variable fract : UNSIGNED (fraction_width downto 0);
constant expon_base : INTEGER := 2**(exponent_width-1) -1; -- exponent
-- offset +1
variable fptype : valid_fpstate;
begin
-- Just return the exponent.
arg := to_01 (x, 'X');
fptype := classfp(arg);
classcase : case fptype is
when isx | nan | quiet_nan =>
-- Return quiet NAN, IEEE754-1985-7.1,1
result := 0;
when pos_denormal | neg_denormal =>
fract (fraction_width) := '0';
fract (fraction_width-1 downto 0) :=
UNSIGNED (to_slv(arg(-1 downto -fraction_width)));
result := find_leftmost (fract, '1') -- Find the first "1"
- fraction_width; -- subtract the length we want
result := -expon_base + 1 + result;
when others =>
expon := SIGNED(arg (exponent_width - 1 downto 0));
expon(exponent_width-1) := not expon(exponent_width-1);
expon := expon + 1;
result := to_integer (expon);
end case classcase;
return result;
end function Logb;
-- returns the unbiased exponent of x
function Logb (
x : UNRESOLVED_float) -- floating point input
return SIGNED is
constant exponent_width : NATURAL := x'high; -- length of FP output exponent
variable result : SIGNED (exponent_width - 1 downto 0); -- result
begin
-- Just return the exponent.
result := to_signed (Logb (x), exponent_width);
return result;
end function Logb;
-- returns the next representable neighbor of x in the direction toward y
function Nextafter (
x, y : UNRESOLVED_float; -- floating point input
constant check_error : BOOLEAN := float_check_error; -- check for errors
constant denormalize : BOOLEAN := float_denormalize)
return UNRESOLVED_float is
constant fraction_width : NATURAL := -mine(x'low, x'low); -- length of FP output fraction
constant exponent_width : NATURAL := x'high; -- length of FP output exponent
function "=" (
l, r : UNRESOLVED_float) -- inputs
return BOOLEAN is
begin -- function "="
return eq (l => l,
r => r,
check_error => false);
end function "=";
function ">" (
l, r : UNRESOLVED_float) -- inputs
return BOOLEAN is
begin -- function ">"
return gt (l => l,
r => r,
check_error => false);
end function ">";
variable fract : UNSIGNED (fraction_width-1 downto 0);
variable expon : UNSIGNED (exponent_width-1 downto 0);
variable sign : STD_ULOGIC;
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable validfpx, validfpy : valid_fpstate; -- Valid FP state
begin -- fp_Nextafter
-- If Y > X, add one to the fraction, otherwise subtract.
validfpx := classfp (x, check_error);
validfpy := classfp (y, check_error);
if validfpx = isx or validfpy = isx then
result := (others => 'X');
return result;
elsif (validfpx = nan or validfpy = nan) then
return nanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif (validfpx = quiet_nan or validfpy = quiet_nan) then
return qnanfp (fraction_width => fraction_width,
exponent_width => exponent_width);
elsif x = y then -- Return X
return x;
else
fract := UNSIGNED (to_slv (x (-1 downto -fraction_width))); -- Fraction
expon := UNSIGNED (x (exponent_width - 1 downto 0)); -- exponent
sign := x(exponent_width); -- sign bit
if (y > x) then
-- Increase the number given
if validfpx = neg_inf then
-- return most negative number
expon := (others => '1');
expon (0) := '0';
fract := (others => '1');
elsif validfpx = pos_zero or validfpx = neg_zero then
-- return smallest denormal number
sign := '0';
expon := (others => '0');
fract := (others => '0');
fract(0) := '1';
elsif validfpx = pos_normal then
if and_reduce (fract) = '1' then -- fraction is all "1".
if and_reduce (expon (exponent_width-1 downto 1)) = '1'
and expon (0) = '0' then
-- Exponent is one away from infinity.
assert NO_WARNING
report float_pkg'instance_name
& "FP_NEXTAFTER: NextAfter overflow"
severity warning;
return pos_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
expon := expon + 1;
fract := (others => '0');
end if;
else
fract := fract + 1;
end if;
elsif validfpx = pos_denormal then
if and_reduce (fract) = '1' then -- fraction is all "1".
-- return smallest possible normal number
expon := (others => '0');
expon(0) := '1';
fract := (others => '0');
else
fract := fract + 1;
end if;
elsif validfpx = neg_normal then
if or_reduce (fract) = '0' then -- fraction is all "0".
if or_reduce (expon (exponent_width-1 downto 1)) = '0' and
expon (0) = '1' then -- Smallest exponent
-- return the largest negative denormal number
expon := (others => '0');
fract := (others => '1');
else
expon := expon - 1;
fract := (others => '1');
end if;
else
fract := fract - 1;
end if;
elsif validfpx = neg_denormal then
if or_reduce (fract(fract'high downto 1)) = '0'
and fract (0) = '1' then -- Smallest possible fraction
return zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
fract := fract - 1;
end if;
end if;
else
-- Decrease the number
if validfpx = pos_inf then
-- return most positive number
expon := (others => '1');
expon (0) := '0';
fract := (others => '1');
elsif validfpx = pos_zero
or classfp (x) = neg_zero then
-- return smallest negative denormal number
sign := '1';
expon := (others => '0');
fract := (others => '0');
fract(0) := '1';
elsif validfpx = neg_normal then
if and_reduce (fract) = '1' then -- fraction is all "1".
if and_reduce (expon (exponent_width-1 downto 1)) = '1'
and expon (0) = '0' then
-- Exponent is one away from infinity.
assert NO_WARNING
report float_pkg'instance_name
& "FP_NEXTAFTER: NextAfter overflow"
severity warning;
return neg_inffp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
expon := expon + 1; -- Fraction overflow
fract := (others => '0');
end if;
else
fract := fract + 1;
end if;
elsif validfpx = neg_denormal then
if and_reduce (fract) = '1' then -- fraction is all "1".
-- return smallest possible normal number
expon := (others => '0');
expon(0) := '1';
fract := (others => '0');
else
fract := fract + 1;
end if;
elsif validfpx = pos_normal then
if or_reduce (fract) = '0' then -- fraction is all "0".
if or_reduce (expon (exponent_width-1 downto 1)) = '0' and
expon (0) = '1' then -- Smallest exponent
-- return the largest positive denormal number
expon := (others => '0');
fract := (others => '1');
else
expon := expon - 1;
fract := (others => '1');
end if;
else
fract := fract - 1;
end if;
elsif validfpx = pos_denormal then
if or_reduce (fract(fract'high downto 1)) = '0'
and fract (0) = '1' then -- Smallest possible fraction
return zerofp (fraction_width => fraction_width,
exponent_width => exponent_width);
else
fract := fract - 1;
end if;
end if;
end if;
result (-1 downto -fraction_width) := UNRESOLVED_float(fract);
result (exponent_width -1 downto 0) := UNRESOLVED_float(expon);
result (exponent_width) := sign;
return result;
end if;
end function Nextafter;
-- Returns True if X is unordered with Y.
function Unordered (
x, y : UNRESOLVED_float) -- floating point input
return BOOLEAN is
variable lfptype, rfptype : valid_fpstate;
begin
lfptype := classfp (x);
rfptype := classfp (y);
if (lfptype = nan or lfptype = quiet_nan or
rfptype = nan or rfptype = quiet_nan or
lfptype = isx or rfptype = isx) then
return true;
else
return false;
end if;
end function Unordered;
function Finite (
x : UNRESOLVED_float)
return BOOLEAN is
variable fp_state : valid_fpstate; -- fp state
begin
fp_state := Classfp (x);
if (fp_state = pos_inf) or (fp_state = neg_inf) then
return true;
else
return false;
end if;
end function Finite;
function Isnan (
x : UNRESOLVED_float)
return BOOLEAN is
variable fp_state : valid_fpstate; -- fp state
begin
fp_state := Classfp (x);
if (fp_state = nan) or (fp_state = quiet_nan) then
return true;
else
return false;
end if;
end function Isnan;
-- Function to return constants.
function zerofp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float is
constant result : UNRESOLVED_float (exponent_width downto -fraction_width) :=
(others => '0'); -- zero
begin
return result;
end function zerofp;
function nanfp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width) :=
(others => '0'); -- zero
begin
result (exponent_width-1 downto 0) := (others => '1');
-- Exponent all "1"
result (-1) := '1'; -- MSB of Fraction "1"
-- Note: From W. Khan "IEEE Standard 754 for Binary Floating Point"
-- The difference between a signaling NAN and a quiet NAN is that
-- the MSB of the Fraction is a "1" in a Signaling NAN, and is a
-- "0" in a quiet NAN.
return result;
end function nanfp;
function qnanfp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width) :=
(others => '0'); -- zero
begin
result (exponent_width-1 downto 0) := (others => '1');
-- Exponent all "1"
result (-fraction_width) := '1'; -- LSB of Fraction "1"
-- (Could have been any bit)
return result;
end function qnanfp;
function pos_inffp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width) :=
(others => '0'); -- zero
begin
result (exponent_width-1 downto 0) := (others => '1'); -- Exponent all "1"
return result;
end function pos_inffp;
function neg_inffp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width) :=
(others => '0'); -- zero
begin
result (exponent_width downto 0) := (others => '1'); -- top bits all "1"
return result;
end function neg_inffp;
function neg_zerofp (
constant exponent_width : NATURAL := float_exponent_width; -- exponent
constant fraction_width : NATURAL := float_fraction_width) -- fraction
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width) :=
(others => '0'); -- zero
begin
result (exponent_width) := '1';
return result;
end function neg_zerofp;
-- size_res versions
function zerofp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float is
begin
return zerofp (
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function zerofp;
function nanfp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float is
begin
return nanfp (
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function nanfp;
function qnanfp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float is
begin
return qnanfp (
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function qnanfp;
function pos_inffp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float is
begin
return pos_inffp (
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function pos_inffp;
function neg_inffp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float is
begin
return neg_inffp (
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function neg_inffp;
function neg_zerofp (
size_res : UNRESOLVED_float) -- variable is only use for sizing
return UNRESOLVED_float is
begin
return neg_zerofp (
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function neg_zerofp;
-- rtl_synthesis off
-- pragma synthesis_off
-- Textio functions
-- purpose: writes float into a line (NOTE changed basetype)
type MVL9plus is ('U', 'X', '0', '1', 'Z', 'W', 'L', 'H', '-', error);
type char_indexed_by_MVL9 is array (STD_ULOGIC) of CHARACTER;
type MVL9_indexed_by_char is array (CHARACTER) of STD_ULOGIC;
type MVL9plus_indexed_by_char is array (CHARACTER) of MVL9plus;
constant MVL9_to_char : char_indexed_by_MVL9 := "UX01ZWLH-";
constant char_to_MVL9 : MVL9_indexed_by_char :=
('U' => 'U', 'X' => 'X', '0' => '0', '1' => '1', 'Z' => 'Z',
'W' => 'W', 'L' => 'L', 'H' => 'H', '-' => '-', others => 'U');
constant char_to_MVL9plus : MVL9plus_indexed_by_char :=
('U' => 'U', 'X' => 'X', '0' => '0', '1' => '1', 'Z' => 'Z',
'W' => 'W', 'L' => 'L', 'H' => 'H', '-' => '-', others => error);
constant NUS : STRING(2 to 1) := (others => ' ');
-- %%% Replicated textio functions
constant NBSP : CHARACTER := CHARACTER'val(160); -- space character
function to_ostring (value : STD_LOGIC_VECTOR) return STRING is
constant ne : INTEGER := (value'length+2)/3;
variable pad : STD_LOGIC_VECTOR(0 to (ne*3 - value'length) - 1);
variable ivalue : STD_LOGIC_VECTOR(0 to ne*3 - 1);
variable result : STRING(1 to ne);
variable tri : STD_LOGIC_VECTOR(0 to 2);
begin
if value'length < 1 then
return NUS;
else
if value (value'left) = 'Z' then
pad := (others => 'Z');
else
pad := (others => '0');
end if;
ivalue := pad & value;
for i in 0 to ne-1 loop
tri := To_X01Z(ivalue(3*i to 3*i+2));
case tri is
when o"0" => result(i+1) := '0';
when o"1" => result(i+1) := '1';
when o"2" => result(i+1) := '2';
when o"3" => result(i+1) := '3';
when o"4" => result(i+1) := '4';
when o"5" => result(i+1) := '5';
when o"6" => result(i+1) := '6';
when o"7" => result(i+1) := '7';
when "ZZZ" => result(i+1) := 'Z';
when others => result(i+1) := 'X';
end case;
end loop;
return result;
end if;
end function to_ostring;
-------------------------------------------------------------------
function to_hstring (value : STD_LOGIC_VECTOR) return STRING is
constant ne : INTEGER := (value'length+3)/4;
variable pad : STD_LOGIC_VECTOR(0 to (ne*4 - value'length) - 1);
variable ivalue : STD_LOGIC_VECTOR(0 to ne*4 - 1);
variable result : STRING(1 to ne);
variable quad : STD_LOGIC_VECTOR(0 to 3);
begin
if value'length < 1 then
return NUS;
else
if value (value'left) = 'Z' then
pad := (others => 'Z');
else
pad := (others => '0');
end if;
ivalue := pad & value;
for i in 0 to ne-1 loop
quad := To_X01Z(ivalue(4*i to 4*i+3));
case quad is
when x"0" => result(i+1) := '0';
when x"1" => result(i+1) := '1';
when x"2" => result(i+1) := '2';
when x"3" => result(i+1) := '3';
when x"4" => result(i+1) := '4';
when x"5" => result(i+1) := '5';
when x"6" => result(i+1) := '6';
when x"7" => result(i+1) := '7';
when x"8" => result(i+1) := '8';
when x"9" => result(i+1) := '9';
when x"A" => result(i+1) := 'A';
when x"B" => result(i+1) := 'B';
when x"C" => result(i+1) := 'C';
when x"D" => result(i+1) := 'D';
when x"E" => result(i+1) := 'E';
when x"F" => result(i+1) := 'F';
when "ZZZZ" => result(i+1) := 'Z';
when others => result(i+1) := 'X';
end case;
end loop;
return result;
end if;
end function to_hstring;
procedure Char2TriBits (C : CHARACTER;
RESULT : out STD_LOGIC_VECTOR(2 downto 0);
GOOD : out BOOLEAN;
ISSUE_ERROR : in BOOLEAN) is
begin
case c is
when '0' => result := o"0"; good := true;
when '1' => result := o"1"; good := true;
when '2' => result := o"2"; good := true;
when '3' => result := o"3"; good := true;
when '4' => result := o"4"; good := true;
when '5' => result := o"5"; good := true;
when '6' => result := o"6"; good := true;
when '7' => result := o"7"; good := true;
when 'Z' => result := "ZZZ"; good := true;
when 'X' => result := "XXX"; good := true;
when others =>
assert not ISSUE_ERROR
report float_pkg'instance_name
& "OREAD Error: Read a '" & c &
"', expected an Octal character (0-7)."
severity error;
result := "UUU";
good := false;
end case;
end procedure Char2TriBits;
-- Hex Read and Write procedures for STD_ULOGIC_VECTOR.
-- Modified from the original to be more forgiving.
procedure Char2QuadBits (C : CHARACTER;
RESULT : out STD_LOGIC_VECTOR(3 downto 0);
GOOD : out BOOLEAN;
ISSUE_ERROR : in BOOLEAN) is
begin
case c is
when '0' => result := x"0"; good := true;
when '1' => result := x"1"; good := true;
when '2' => result := x"2"; good := true;
when '3' => result := x"3"; good := true;
when '4' => result := x"4"; good := true;
when '5' => result := x"5"; good := true;
when '6' => result := x"6"; good := true;
when '7' => result := x"7"; good := true;
when '8' => result := x"8"; good := true;
when '9' => result := x"9"; good := true;
when 'A' | 'a' => result := x"A"; good := true;
when 'B' | 'b' => result := x"B"; good := true;
when 'C' | 'c' => result := x"C"; good := true;
when 'D' | 'd' => result := x"D"; good := true;
when 'E' | 'e' => result := x"E"; good := true;
when 'F' | 'f' => result := x"F"; good := true;
when 'Z' => result := "ZZZZ"; good := true;
when 'X' => result := "XXXX"; good := true;
when others =>
assert not ISSUE_ERROR
report float_pkg'instance_name
& "HREAD Error: Read a '" & c &
"', expected a Hex character (0-F)."
severity error;
result := "UUUU";
good := false;
end case;
end procedure Char2QuadBits;
procedure OREAD (L : inout LINE; VALUE : out STD_LOGIC_VECTOR;
GOOD : out BOOLEAN) is
variable ok : BOOLEAN;
variable c : CHARACTER;
constant ne : INTEGER := (VALUE'length+2)/3;
constant pad : INTEGER := ne*3 - VALUE'length;
variable sv : STD_LOGIC_VECTOR(0 to ne*3 - 1);
variable s : STRING(1 to ne-1);
begin
VALUE := (VALUE'range => 'U');
loop -- skip white space
read(L, c, ok);
exit when (ok = false) or ((c /= ' ') and (c /= NBSP) and (c /= HT));
end loop;
-- Bail out if there was a bad read
if not ok then
good := false;
return;
end if;
Char2TriBits(c, sv(0 to 2), ok, false);
if not ok then
good := false;
return;
end if;
read(L, s, ok);
if not ok then
good := false;
return;
end if;
for i in 1 to ne-1 loop
Char2TriBits(s(i), sv(3*i to 3*i+2), ok, false);
if not ok then
good := false;
return;
end if;
end loop;
if or_reduce (sv (0 to pad-1)) = '1' then -- %%% replace with "or"
good := false; -- vector was truncated.
else
good := true;
VALUE := sv (pad to sv'high);
end if;
end procedure OREAD;
procedure HREAD (L : inout LINE; VALUE : out STD_LOGIC_VECTOR;
GOOD : out BOOLEAN) is
variable ok : BOOLEAN;
variable c : CHARACTER;
constant ne : INTEGER := (VALUE'length+3)/4;
constant pad : INTEGER := ne*4 - VALUE'length;
variable sv : STD_LOGIC_VECTOR(0 to ne*4 - 1);
variable s : STRING(1 to ne-1);
begin
VALUE := (VALUE'range => 'U');
loop -- skip white space
read(l, c, ok);
exit when (ok = false) or ((c /= ' ') and (c /= NBSP) and (c /= HT));
end loop;
-- Bail out if there was a bad read
if not ok then
good := false;
return;
end if;
Char2QuadBits(c, sv(0 to 3), ok, false);
if not ok then
good := false;
return;
end if;
read(L, s, ok);
if not ok then
good := false;
return;
end if;
for i in 1 to ne-1 loop
Char2QuadBits(s(i), sv(4*i to 4*i+3), ok, false);
if not ok then
good := false;
return;
end if;
end loop;
if or_reduce (sv (0 to pad-1)) = '1' then -- %%% replace with "or"
good := false; -- vector was truncated.
else
VALUE := sv (pad to sv'high);
good := true;
end if;
end procedure HREAD;
-- %%% END replicated textio functions
procedure WRITE (
L : inout LINE; -- input line
VALUE : in UNRESOLVED_float; -- floating point input
JUSTIFIED : in SIDE := right;
FIELD : in WIDTH := 0) is
variable s : STRING(1 to value'high - value'low +3);
variable sindx : INTEGER;
begin -- function write
s(1) := MVL9_to_char(STD_ULOGIC(VALUE(VALUE'high)));
s(2) := ':';
sindx := 3;
for i in VALUE'high-1 downto 0 loop
s(sindx) := MVL9_to_char(STD_ULOGIC(VALUE(i)));
sindx := sindx + 1;
end loop;
s(sindx) := ':';
sindx := sindx + 1;
for i in -1 downto VALUE'low loop
s(sindx) := MVL9_to_char(STD_ULOGIC(VALUE(i)));
sindx := sindx + 1;
end loop;
WRITE (L, s, JUSTIFIED, FIELD);
end procedure WRITE;
procedure READ (L : inout LINE; VALUE : out UNRESOLVED_float) is
-- Possible data: 0:0000:0000000
-- 000000000000
variable c : CHARACTER;
variable readOk : BOOLEAN;
variable i : INTEGER; -- index variable
begin -- READ
loop -- skip white space
READ (l, c, readOk);
exit when ((readOk = false) or ((c /= ' ') and (c /= CR) and (c /= HT)));
end loop;
for i in value'high downto value'low loop
value(i) := 'X';
end loop;
i := value'high;
readloop : loop
if readOk = false then -- Bail out if there was a bad read
report float_pkg'instance_name
& "READ(float): "
& "Error end of file encountered."
severity error;
return;
elsif c = ' ' or c = CR or c = HT then -- reading done.
if (i /= value'low) then
report float_pkg'instance_name
& "READ(float): "
& "Warning: Value truncated."
severity warning;
return;
end if;
elsif c = ':' or c = '.' then -- separator, ignore
if not (i = -1 or i = value'high-1) then
report float_pkg'instance_name
& "READ(float): "
& "Warning: Separator point does not match number format: '"
& c & "' encountered at location " & INTEGER'image(i) & "."
severity warning;
end if;
elsif (char_to_MVL9plus(c) = error) then
report float_pkg'instance_name
& "READ(float): "
& "Error: Character '" & c & "' read, expected STD_ULOGIC literal."
severity error;
return;
else
value (i) := char_to_MVL9(c);
i := i - 1;
if i < value'low then
return;
end if;
end if;
READ (l, c, readOk);
end loop readloop;
end procedure READ;
procedure READ (L : inout LINE; VALUE : out UNRESOLVED_float; GOOD : out BOOLEAN) is
-- Possible data: 0:0000:0000000
-- 000000000000
variable c : CHARACTER;
variable i : INTEGER; -- index variable
variable readOk : BOOLEAN;
begin -- READ
loop -- skip white space
READ (l, c, readOk);
exit when ((readOk = false) or ((c /= ' ') and (c /= CR) and (c /= HT)));
end loop;
for i in value'high downto value'low loop
value(i) := 'X';
end loop;
i := value'high;
good := true;
readloop : loop
if readOk = false then -- Bail out if there was a bad read
good := false;
return;
elsif c = ' ' or c = CR or c = HT then -- reading done
good := false;
return;
elsif c = ':' or c = '.' then -- separator, ignore
good := (i = -1 or i = value'high-1);
elsif (char_to_MVL9plus(c) = error) then
good := false;
return;
else
value (i) := char_to_MVL9(c);
i := i - 1;
if i < value'low then
return;
end if;
end if;
READ (l, c, readOk);
end loop readloop;
end procedure READ;
procedure OWRITE (
L : inout LINE; -- access type (pointer)
VALUE : in UNRESOLVED_float; -- value to write
JUSTIFIED : in SIDE := right; -- which side to justify text
FIELD : in WIDTH := 0) is -- width of field
begin
WRITE (L => L,
VALUE => to_ostring(VALUE),
JUSTIFIED => JUSTIFIED,
FIELD => FIELD);
end procedure OWRITE;
procedure OREAD (L : inout LINE; VALUE : out UNRESOLVED_float) is
constant ne : INTEGER := ((value'length+2)/3) * 3; -- pad
variable slv : STD_LOGIC_VECTOR (ne-1 downto 0); -- slv
variable dummy : CHARACTER; -- to read the "."
variable igood : BOOLEAN;
variable nybble : STD_LOGIC_VECTOR (2 downto 0); -- 3 bits
variable i : INTEGER;
begin
OREAD (L => L,
VALUE => nybble,
good => igood);
assert (igood)
report float_pkg'instance_name
& "OREAD: Failed to skip white space " & L.all
severity error;
i := ne-1 - 3; -- Top - 3
slv (ne-1 downto i+1) := nybble;
while (i /= -1) and igood and L.all'length /= 0 loop
if (L.all(1) = '.') or (L.all(1) = ':') then
read (L, dummy);
else
OREAD (L => L,
VALUE => nybble,
good => igood);
assert (igood)
report float_pkg'instance_name
& "OREAD: Failed to read the string " & L.all
severity error;
slv (i downto i-2) := nybble;
i := i - 3;
end if;
end loop;
assert igood and -- We did not get another error
(i = -1) and -- We read everything, and high bits 0
(or_reduce (slv(ne-1 downto VALUE'high-VALUE'low+1)) = '0')
report float_pkg'instance_name
& "OREAD: Vector truncated."
severity error;
value := to_float (slv(VALUE'high-VALUE'low downto 0),
value'high, -value'low);
end procedure OREAD;
procedure OREAD(L : inout LINE; VALUE : out UNRESOLVED_float; GOOD : out BOOLEAN) is
constant ne : INTEGER := ((value'length+2)/3) * 3; -- pad
variable slv : STD_LOGIC_VECTOR (ne-1 downto 0); -- slv
variable dummy : CHARACTER; -- to read the "."
variable igood : BOOLEAN;
variable nybble : STD_LOGIC_VECTOR (2 downto 0); -- 3 bits
variable i : INTEGER;
begin
OREAD (L => L,
VALUE => nybble,
good => igood);
i := ne-1 - 3; -- Top - 3
slv (ne-1 downto i+1) := nybble;
while (i /= -1) and igood and L.all'length /= 0 loop
if (L.all(1) = '.') or (L.all(1) = ':') then
read (L, dummy, igood);
else
OREAD (L => L,
VALUE => nybble,
good => igood);
slv (i downto i-2) := nybble;
i := i - 3;
end if;
end loop;
good := igood and -- We did not get another error
(i = -1) and -- We read everything, and high bits 0
(or_reduce (slv(ne-1 downto VALUE'high-VALUE'low+1)) = '0');
value := to_float (slv(VALUE'high-VALUE'low downto 0),
value'high, -value'low);
end procedure OREAD;
procedure HWRITE (
L : inout LINE; -- access type (pointer)
VALUE : in UNRESOLVED_float; -- value to write
JUSTIFIED : in SIDE := right; -- which side to justify text
FIELD : in WIDTH := 0) is -- width of field
begin
WRITE (L => L,
VALUE => to_hstring(VALUE),
JUSTIFIED => JUSTIFIED,
FIELD => FIELD);
end procedure HWRITE;
procedure HREAD (L : inout LINE; VALUE : out UNRESOLVED_float) is
constant ne : INTEGER := ((value'length+3)/4) * 4; -- pad
variable slv : STD_LOGIC_VECTOR (ne-1 downto 0); -- slv
variable dummy : CHARACTER; -- to read the "."
variable igood : BOOLEAN;
variable nybble : STD_LOGIC_VECTOR (3 downto 0); -- 4 bits
variable i : INTEGER;
begin
HREAD (L => L,
VALUE => nybble,
good => igood);
assert (igood)
report float_pkg'instance_name
& "HREAD: Failed to skip white space " & L.all
severity error;
i := ne - 1 - 4; -- Top - 4
slv (ne -1 downto i+1) := nybble;
while (i /= -1) and igood and L.all'length /= 0 loop
if (L.all(1) = '.') or (L.all(1) = ':') then
read (L, dummy);
else
HREAD (L => L,
VALUE => nybble,
good => igood);
assert (igood)
report float_pkg'instance_name
& "HREAD: Failed to read the string " & L.all
severity error;
slv (i downto i-3) := nybble;
i := i - 4;
end if;
end loop;
assert igood and -- We did not get another error
(i = -1) and -- We read everything
(or_reduce (slv(ne-1 downto VALUE'high-VALUE'low+1)) = '0')
report float_pkg'instance_name
& "HREAD: Vector truncated."
severity error;
value := to_float (slv(VALUE'high-VALUE'low downto 0),
value'high, -value'low);
end procedure HREAD;
procedure HREAD (L : inout LINE; VALUE : out UNRESOLVED_float; GOOD : out BOOLEAN) is
constant ne : INTEGER := ((value'length+3)/4) * 4; -- pad
variable slv : STD_LOGIC_VECTOR (ne-1 downto 0); -- slv
variable dummy : CHARACTER; -- to read the "."
variable igood : BOOLEAN;
variable nybble : STD_LOGIC_VECTOR (3 downto 0); -- 4 bits
variable i : INTEGER;
begin
HREAD (L => L,
VALUE => nybble,
good => igood);
i := ne - 1 - 4; -- Top - 4
slv (ne-1 downto i+1) := nybble;
while (i /= -1) and igood and L.all'length /= 0 loop
if (L.all(1) = '.') or (L.all(1) = ':') then
read (L, dummy, igood);
else
HREAD (L => L,
VALUE => nybble,
good => igood);
slv (i downto i-3) := nybble;
i := i - 4;
end if;
end loop;
good := igood and -- We did not get another error
(i = -1) and -- We read everything, and high bits 0
(or_reduce (slv(ne-1 downto VALUE'high-VALUE'low+1)) = '0');
value := to_float (slv(VALUE'high-VALUE'low downto 0),
value'high, -value'low);
end procedure HREAD;
function to_string (value : UNRESOLVED_float) return STRING is
variable s : STRING(1 to value'high - value'low +3);
variable sindx : INTEGER;
begin -- function write
s(1) := MVL9_to_char(STD_ULOGIC(VALUE(VALUE'high)));
s(2) := ':';
sindx := 3;
for i in VALUE'high-1 downto 0 loop
s(sindx) := MVL9_to_char(STD_ULOGIC(VALUE(i)));
sindx := sindx + 1;
end loop;
s(sindx) := ':';
sindx := sindx + 1;
for i in -1 downto VALUE'low loop
s(sindx) := MVL9_to_char(STD_ULOGIC(VALUE(i)));
sindx := sindx + 1;
end loop;
return s;
end function to_string;
function to_hstring (value : UNRESOLVED_float) return STRING is
variable slv : STD_LOGIC_VECTOR (value'length-1 downto 0);
begin
floop : for i in slv'range loop
slv(i) := to_X01Z (value(i + value'low));
end loop floop;
return to_hstring (slv);
end function to_hstring;
function to_ostring (value : UNRESOLVED_float) return STRING is
variable slv : STD_LOGIC_VECTOR (value'length-1 downto 0);
begin
floop : for i in slv'range loop
slv(i) := to_X01Z (value(i + value'low));
end loop floop;
return to_ostring (slv);
end function to_ostring;
function from_string (
bstring : STRING; -- binary string
constant exponent_width : NATURAL := float_exponent_width;
constant fraction_width : NATURAL := float_fraction_width)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable L : LINE;
variable good : BOOLEAN;
begin
L := new STRING'(bstring);
READ (L, result, good);
deallocate (L);
assert (good)
report float_pkg'instance_name
& "from_string: Bad string " & bstring
severity error;
return result;
end function from_string;
function from_ostring (
ostring : STRING; -- Octal string
constant exponent_width : NATURAL := float_exponent_width;
constant fraction_width : NATURAL := float_fraction_width)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable L : LINE;
variable good : BOOLEAN;
begin
L := new STRING'(ostring);
OREAD (L, result, good);
deallocate (L);
assert (good)
report float_pkg'instance_name
& "from_ostring: Bad string " & ostring
severity error;
return result;
end function from_ostring;
function from_hstring (
hstring : STRING; -- hex string
constant exponent_width : NATURAL := float_exponent_width;
constant fraction_width : NATURAL := float_fraction_width)
return UNRESOLVED_float is
variable result : UNRESOLVED_float (exponent_width downto -fraction_width);
variable L : LINE;
variable good : BOOLEAN;
begin
L := new STRING'(hstring);
HREAD (L, result, good);
deallocate (L);
assert (good)
report float_pkg'instance_name
& "from_hstring: Bad string " & hstring
severity error;
return result;
end function from_hstring;
function from_string (
bstring : STRING; -- binary string
size_res : UNRESOLVED_float) -- used for sizing only
return UNRESOLVED_float is
begin
return from_string (bstring => bstring,
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function from_string;
function from_ostring (
ostring : STRING; -- Octal string
size_res : UNRESOLVED_float) -- used for sizing only
return UNRESOLVED_float is
begin
return from_ostring (ostring => ostring,
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function from_ostring;
function from_hstring (
hstring : STRING; -- hex string
size_res : UNRESOLVED_float) -- used for sizing only
return UNRESOLVED_float is
begin
return from_hstring (hstring => hstring,
exponent_width => size_res'high,
fraction_width => -size_res'low);
end function from_hstring;
-- rtl_synthesis on
-- pragma synthesis_on
function to_float (
arg : STD_LOGIC_VECTOR;
constant exponent_width : NATURAL := float_exponent_width; -- length of FP output exponent
constant fraction_width : NATURAL := float_fraction_width) -- length of FP output fraction
return UNRESOLVED_float is
begin
return to_float (
arg => to_stdulogicvector (arg),
exponent_width => exponent_width,
fraction_width => fraction_width);
end function to_float;
function to_float (
arg : STD_LOGIC_VECTOR;
size_res : UNRESOLVED_float)
return UNRESOLVED_float is
begin
return to_float (
arg => to_stdulogicvector (arg),
size_res => size_res);
end function to_float;
end package body float_pkg;
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