jens
ee04924d42
Committed on the Free edition of March Hare Software CVSNT Server. Upgrade to CVS Suite for more features and support: http://march-hare.com/cvsnt/ git-svn-id: http://moon:8086/svn/vhdl/trunk@576 cc03376c-175c-47c8-b038-4cd826a8556b
119 lines
2.5 KiB
VHDL
119 lines
2.5 KiB
VHDL
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-- $Header: /tmp/cvsroot/VHDL/lib/misc/utils_pkg.vhd,v 1.3 2009-11-03 20:38:30 Jens Exp $
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-----------------------------------------------------------------------
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library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use IEEE.NUMERIC_STD.ALL;
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use IEEE.MATH_REAL.ALL;
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package utils_pkg is
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-- Constants
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-- Functions
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function NextPowerOfTwo(x : real) return real;
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function NextExpBaseTwo(x : real) return real;
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function NextPowerOfTwo(x : natural) return natural;
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function NextExpBaseTwo(x : natural) return natural;
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function GCD(a, b : natural) return natural;
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function LCM(a, b : natural) return natural;
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function UTILS_PERIOD_NS(f_in_hz : natural) return real;
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function UTILS_FREQ_M(f_in_hz, f_out_hz : natural) return natural;
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function UTILS_FREQ_D(f_in_hz, f_out_hz : natural) return natural;
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end utils_pkg;
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package body utils_pkg is
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function NextExpBaseTwo(x : real) return real is
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begin
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return ceil(log2(x));
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end NextExpBaseTwo;
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function NextPowerOfTwo(x : real) return real is
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begin
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return 2.0**NextExpBaseTwo(x);
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end NextPowerOfTwo;
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function NextExpBaseTwo(x : natural) return natural is
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begin
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return natural(NextExpBaseTwo(real(x)));
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end NextExpBaseTwo;
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function NextPowerOfTwo(x : natural) return natural is
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begin
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return 2**NextExpBaseTwo(x);
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end NextPowerOfTwo;
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function GCD(a, b : natural) return natural is
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variable aa : natural;
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variable bb : natural;
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begin
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aa := a;
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bb := b;
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while bb /= 0 loop
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if aa > bb then
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aa := aa - bb;
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else
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bb := bb - aa;
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end if;
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end loop;
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return aa;
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end GCD;
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function LCM(a, b : natural) return natural is
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begin
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return (a * b)/GCD(a, b);
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end LCM;
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function UTILS_PERIOD_NS(f_in_hz : natural) return real is
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begin
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return 1.0E9/real(f_in_hz);
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end UTILS_PERIOD_NS;
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function UTILS_FREQ_M(f_in_hz, f_out_hz : natural) return natural is
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variable f_in_mhz : natural;
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variable f_out_mhz : natural;
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variable m : natural;
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begin
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f_in_mhz := f_in_hz/1E6;
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f_out_mhz := f_out_hz/1E6;
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m := f_out_mhz/GCD(f_in_mhz, f_out_mhz);
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if m = 1 then
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m := 2;
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end if;
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return m;
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end UTILS_FREQ_M;
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function UTILS_FREQ_D(f_in_hz, f_out_hz : natural) return natural is
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variable f_in_mhz : natural;
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variable f_out_mhz : natural;
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variable m : natural;
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variable d : natural;
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begin
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m := UTILS_FREQ_M(f_in_hz, f_out_hz);
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f_in_mhz := f_in_hz/1E6;
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f_out_mhz := f_out_hz/1E6;
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d := m*f_in_mhz/f_out_mhz;
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return d;
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end UTILS_FREQ_D;
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end utils_pkg;
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