jens
2edaa4d7cb
git-svn-id: http://moon:8086/svn/vhdl/trunk@1290 cc03376c-175c-47c8-b038-4cd826a8556b
129 lines
4.0 KiB
VHDL
129 lines
4.0 KiB
VHDL
-- ----------------------------------------------------------------------------
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--
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-- Micron Semiconductor Products, Inc.
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--
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-- Copyright 1997, Micron Semiconductor Products, Inc.
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-- All rights reserved.
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--
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-- ----------------------------------------------------------------------------
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LIBRARY work;
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LIBRARY ieee;
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USE ieee.std_logic_1164.ALL;
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PACKAGE mti_pkg IS
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FUNCTION TO_INTEGER (input : BIT) RETURN INTEGER;
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FUNCTION TO_INTEGER (input : STD_LOGIC) RETURN INTEGER;
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FUNCTION TO_INTEGER (input : BIT_VECTOR) RETURN INTEGER;
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FUNCTION TO_INTEGER (input : STD_LOGIC_VECTOR) RETURN INTEGER;
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PROCEDURE TO_BITVECTOR (VARIABLE input : IN INTEGER; VARIABLE output : OUT BIT_VECTOR);
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END mti_pkg;
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PACKAGE BODY mti_pkg IS
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FUNCTION TO_INTEGER (input : BIT) RETURN INTEGER IS
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BEGIN
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CASE input IS
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WHEN '0' => RETURN 0;
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WHEN '1' => RETURN 1;
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WHEN OTHERS => RETURN 0;
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END CASE;
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END TO_INTEGER;
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FUNCTION TO_INTEGER (input : STD_LOGIC) RETURN INTEGER IS
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BEGIN
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CASE input IS
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WHEN '0' | 'L' => RETURN 0;
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WHEN '1' | 'H' => RETURN 1;
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WHEN OTHERS => RETURN 0;
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END CASE;
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END TO_INTEGER;
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FUNCTION TO_INTEGER (input : BIT_VECTOR) RETURN INTEGER IS
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VARIABLE result : INTEGER := 0;
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VARIABLE weight : INTEGER := 1;
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BEGIN
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FOR i IN input'LOW TO input'HIGH LOOP
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IF input(i) = '1' THEN
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result := result + weight;
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END IF;
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weight := weight * 2;
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END LOOP;
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RETURN result;
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END TO_INTEGER;
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FUNCTION TO_INTEGER (input : STD_LOGIC_VECTOR) RETURN INTEGER IS
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VARIABLE result : INTEGER := 0;
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VARIABLE weight : INTEGER := 1;
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BEGIN
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FOR i IN input'LOW TO input'HIGH LOOP
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IF input(i) = '1' OR input(i) = 'H' THEN
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result := result + weight;
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END IF;
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weight := weight * 2;
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END LOOP;
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RETURN result;
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END TO_INTEGER;
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PROCEDURE TO_BITVECTOR (VARIABLE input : IN INTEGER; VARIABLE output : OUT BIT_VECTOR) IS
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VARIABLE work,offset,outputlen,j : INTEGER := 0;
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BEGIN
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--length of vector
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IF output'LENGTH > 32 THEN
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outputlen := 32;
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offset := output'LENGTH - 32;
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IF input >= 0 THEN
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FOR i IN offset-1 DOWNTO 0 LOOP
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output(output'HIGH - i) := '0';
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END LOOP;
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ELSE
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FOR i IN offset-1 DOWNTO 0 LOOP
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output(output'HIGH - i) := '1';
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END LOOP;
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END IF;
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ELSE
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outputlen := output'LENGTH;
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END IF;
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--positive value
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IF (input >= 0) THEN
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work := input;
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j := outputlen - 1;
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FOR i IN 1 to 32 LOOP
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IF j >= 0 then
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IF (work MOD 2) = 0 THEN
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output(output'HIGH-j-offset) := '0';
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ELSE
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output(output'HIGH-j-offset) := '1';
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END IF;
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END IF;
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work := work / 2;
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j := j - 1;
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END LOOP;
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IF outputlen = 32 THEN
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output(output'HIGH) := '0';
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END IF;
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--negative value
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ELSE
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work := (-input) - 1;
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j := outputlen - 1;
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FOR i IN 1 TO 32 LOOP
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IF j>= 0 THEN
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IF (work MOD 2) = 0 THEN
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output(output'HIGH-j-offset) := '1';
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ELSE
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output(output'HIGH-j-offset) := '0';
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END IF;
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END IF;
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work := work / 2;
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j := j - 1;
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END LOOP;
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IF outputlen = 32 THEN
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output(output'HIGH) := '1';
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END IF;
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END IF;
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END TO_BITVECTOR;
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END mti_pkg;
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