108 lines
3.0 KiB
Verilog
108 lines
3.0 KiB
Verilog
/*
|
|
* Copyright (c) 2000 Mark Schellhorn <schellho@nortelnetworks.com>
|
|
*
|
|
* This source code is free software; you can redistribute it
|
|
* and/or modify it in source code form 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.
|
|
*
|
|
* This program 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 this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
|
|
*/
|
|
|
|
/****************************************************************************
|
|
|
|
The following code illustrates an apparent bug in the VCS v5.2 simulator.
|
|
The check for whether or not the memory[0] array element was set correctly
|
|
fails; yet the $display statement immediately after the check shows the
|
|
memory[0] element actually has been set correctly.
|
|
|
|
I've noted that if the $display and the check are reversed, the $display
|
|
is incorrect but the check passes.
|
|
|
|
This appears to be a problem with the simulator's internal scheduler.
|
|
|
|
***************************************************************************/
|
|
|
|
|
|
module bug_test;
|
|
|
|
reg [1:0] temp;
|
|
|
|
initial begin
|
|
|
|
/********** First test. */
|
|
|
|
$display("Running first test.\n");
|
|
|
|
// Try setting memory array in other module using hierarchical
|
|
// references & concatenation.
|
|
temp = 2'h3;
|
|
top.memory.memory[0] = {2'h0,temp};
|
|
top.memory.memory[0] = {top.memory.memory[0],temp};
|
|
|
|
// Check that setting was made correctly
|
|
if (top.memory.memory[0] != {2{temp}}) begin
|
|
$display("ERROR! top.memory.memory[0] failed to get");
|
|
$display("set correctly!");
|
|
end else begin
|
|
$display("PASS! top.memory.memory[0] set correctly.");
|
|
end
|
|
|
|
// Display the value that was checked
|
|
$display("top.memory.memory[0] = %h",top.memory.memory[0]);
|
|
|
|
|
|
|
|
/********** Second test. */
|
|
|
|
$display("\nRunning second test.\n");
|
|
|
|
// Try setting memory array in other module using hierarchical
|
|
// references & concatenation.
|
|
temp = 2'h3;
|
|
top.memory.memory[1] = {2'h0,temp};
|
|
top.memory.memory[1] = {top.memory.memory[1],temp};
|
|
|
|
// Display the value that will be checked
|
|
$display("top.memory.memory[1] = %h",top.memory.memory[1]);
|
|
|
|
// Check that setting was made correctly
|
|
if (top.memory.memory[1] != {2{temp}}) begin
|
|
$display("ERROR! top.memory.memory[1] failed to get");
|
|
$display("set correctly!");
|
|
end else begin
|
|
$display("PASS! top.memory.memory[1] set correctly.");
|
|
end
|
|
|
|
// Display the value that was checked
|
|
$display("top.memory.memory[1] = %h",top.memory.memory[1]);
|
|
|
|
$finish(0);
|
|
|
|
end
|
|
|
|
endmodule
|
|
|
|
// Module containing a memory array
|
|
module memory;
|
|
|
|
reg [3:0] memory [0:1];
|
|
|
|
endmodule
|
|
|
|
// Module to instantiate test and memory modules
|
|
module top;
|
|
|
|
bug_test bug_test();
|
|
memory memory();
|
|
|
|
endmodule
|