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-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs is free software; you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation; either version 2 of the License, or (at
-- your option) any later version.
-- VESTs is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: bv_images_body.vhd,v 1.3 2001-10-26 16:29:33 paw Exp $
-- $Revision: 1.3 $
--
-- ---------------------------------------------------------------------
--------------------------------------------------------------------------
--
-- bv_images package body.
--
-- Functions that return the string image of values.
-- Each image is a correctly formed literal according to the
-- rules of VHDL-93.
--
--------------------------------------------------------------------------
package body bv_images is
-- Image of bit vector as binary bit string literal
-- (in the format B"...")
-- Length of result is bv'length + 3
function image (bv : in bit_vector) return string is
alias bv_norm : bit_vector(1 to bv'length) is bv;
variable result : string(1 to bv'length + 3);
begin
result(1) := 'B';
result(2) := '"';
for index in bv_norm'range loop
if bv_norm(index) = '0' then
result(index + 2) := '0';
else
result(index + 2) := '1';
end if;
end loop;
result(bv'length + 3) := '"';
return result;
end image;
----------------------------------------------------------------
-- Image of bit vector as octal bit string literal
-- (in the format O"...")
-- Length of result is (bv'length+2)/3 + 3
function image_octal (bv : in bit_vector) return string is
constant nr_digits : natural := (bv'length + 2) / 3;
variable result : string(1 to nr_digits + 3);
variable bits : bit_vector(0 to 3*nr_digits - 1) := (others => '0');
variable three_bits : bit_vector(0 to 2);
variable digit : character;
begin
result(1) := 'O';
result(2) := '"';
bits(bits'right - bv'length + 1 to bits'right) := bv;
for index in 0 to nr_digits - 1 loop
three_bits := bits(3*index to 3*index + 2);
case three_bits is
when b"000" =>
digit := '0';
when b"001" =>
digit := '1';
when b"010" =>
digit := '2';
when b"011" =>
digit := '3';
when b"100" =>
digit := '4';
when b"101" =>
digit := '5';
when b"110" =>
digit := '6';
when b"111" =>
digit := '7';
end case;
result(index + 3) := digit;
end loop;
result(nr_digits + 3) := '"';
return result;
end image_octal;
----------------------------------------------------------------
-- Image of bit vector as hex bit string literal
-- (in the format X"...")
-- Length of result is (bv'length+3)/4 + 3
function image_hex (bv : in bit_vector) return string is
constant nr_digits : natural := (bv'length + 3) / 4;
variable result : string(1 to nr_digits + 3);
variable bits : bit_vector(0 to 4*nr_digits - 1) := (others => '0');
variable four_bits : bit_vector(0 to 3);
variable digit : character;
begin
result(1) := 'X';
result(2) := '"';
bits(bits'right - bv'length + 1 to bits'right) := bv;
for index in 0 to nr_digits - 1 loop
four_bits := bits(4*index to 4*index + 3);
case four_bits is
when b"0000" =>
digit := '0';
when b"0001" =>
digit := '1';
when b"0010" =>
digit := '2';
when b"0011" =>
digit := '3';
when b"0100" =>
digit := '4';
when b"0101" =>
digit := '5';
when b"0110" =>
digit := '6';
when b"0111" =>
digit := '7';
when b"1000" =>
digit := '8';
when b"1001" =>
digit := '9';
when b"1010" =>
digit := 'A';
when b"1011" =>
digit := 'B';
when b"1100" =>
digit := 'C';
when b"1101" =>
digit := 'D';
when b"1110" =>
digit := 'E';
when b"1111" =>
digit := 'F';
end case;
result(index + 3) := digit;
end loop;
result(nr_digits + 3) := '"';
return result;
end image_hex;
end bv_images;
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