| /* |
| * Copyright (c) 2000 Yasuhisa Kato <ykato@mac.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 |
| */ |
| |
| module busm ( clk, iB, oB ); |
| input clk ; |
| input [3:0] iB ; |
| output [3:0] oB ; |
| reg [3:0] r ; |
| |
| assign oB = r ; |
| always @(posedge clk) r <= iB ; |
| |
| endmodule |
| |
| module main; |
| reg a, b, c, d ; |
| |
| reg clk ; |
| initial begin clk = 0 ; forever #5 clk = ~clk ; end |
| initial begin a = 0 ; c = 0 ; #100 $finish; end |
| |
| wire e0, f0, g0, h0 ; |
| wire e, f, g, h ; |
| wire [3:0] ii, oo ; |
| |
| always @(posedge clk) a <= ~a ; |
| always @(posedge clk) b <= a ; |
| always @(posedge clk) c <= c ^ a ; |
| always @(posedge clk) d <= ~c ; |
| |
| assign ii = {a, b, c, d} ; |
| assign {e0, f0, g0, h0} = oo ; |
| |
| busm M0 ( clk, ii, oo ); |
| busm M1 ( clk, {a,b,c,d}, {e,f,g,h} ); |
| |
| always @(posedge clk) |
| $display("%h %h %h %h : %b : %h %h %h %h : %b : %h %h %h %h", |
| a, b, c, d, M0.r, e0, f0, g0, h0, |
| M1.r, e, f, g, h |
| |
| ); |
| |
| endmodule |
| |
| // expecting result |
| // 0 x 0 x : xxxx : z z z z : xxxx : z z z z |
| // 1 0 0 1 : 0z0z : 0 z 0 z : 0z0z : 0 z 0 z |
| // 0 1 1 1 : 1001 : 1 0 0 1 : 1001 : 1 0 0 1 |
| // 1 0 1 0 : 0111 : 0 1 1 1 : 0111 : 0 1 1 1 |
| // 0 1 0 0 : 1010 : 1 0 1 0 : 1010 : 1 0 1 0 |
| // 1 0 0 1 : 0100 : 0 1 0 0 : 0100 : 0 1 0 0 |
| // 0 1 1 1 : 1001 : 1 0 0 1 : 1001 : 1 0 0 1 |
| // 1 0 1 0 : 0111 : 0 1 1 1 : 0111 : 0 1 1 1 |
| // 0 1 0 0 : 1010 : 1 0 1 0 : 1010 : 1 0 1 0 |
| // 1 0 0 1 : 0100 : 0 1 0 0 : 0100 : 0 1 0 0 |