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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 zmux is
end entity zmux;
library util; use util.stimulus_generators.all;
architecture test of zmux is
signal sel0, sel1, d0, d1, d2, d3 : bit := '0';
signal functional_z, equivalent_z : bit;
begin
functional_mux : block is
port ( z : out bit );
port map ( z => functional_z );
begin
-- code from book
zmux : z <= d0 when sel1 = '0' and sel0 = '0' else
d1 when sel1 = '0' and sel0 = '1' else
d2 when sel1 = '1' and sel0 = '0' else
d3 when sel1 = '1' and sel0 = '1';
-- end code from book
end block functional_mux;
--------------------------------------------------
equivalent_mux : block is
port ( z : out bit );
port map ( z => equivalent_z );
begin
-- code from book
zmux : process is
begin
if sel1 = '0' and sel0 = '0' then
z <= d0;
elsif sel1 = '0' and sel0 = '1' then
z <= d1;
elsif sel1 = '1' and sel0 = '0' then
z <= d2;
elsif sel1 = '1' and sel0 = '1' then
z <= d3;
end if;
wait on d0, d1, d2, d3, sel0, sel1;
end process zmux;
-- end code from book
end block equivalent_mux;
--------------------------------------------------
stimulus :
all_possible_values( bv(0) => sel0, bv(1) => sel1,
bv(2) => d0, bv(3) => d1,
bv(4) => d2, bv(5) => d3,
delay_between_values => 10 ns );
verifier :
assert functional_z = equivalent_z
report "Functional and equivalent models give different results";
end architecture test;
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