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-- Copyright (C) 2002 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
entity negate is
end entity negate;
architecture test of negate is
subtype word32 is bit_vector(31 downto 0);
-- code in book
procedure negate ( a : inout word32 ) is
variable carry_in : bit := '1';
variable carry_out : bit;
begin
a := not a;
for index in a'reverse_range loop
carry_out := a(index) and carry_in;
a(index) := a(index) xor carry_in;
carry_in := carry_out;
end loop;
end procedure negate;
-- end code in book
begin
stimulus : process is
-- code in book (in text)
variable op1 : word32;
-- . . .
-- end code in book
begin
op1 := X"0000_0002";
-- code in book (in text)
negate ( op1 );
-- end code in book
wait;
end process stimulus;
end architecture test;
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