// // Copyright (c) 1999 Stephen Williams // // 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 // // SDW - Validate always case ( reg_value) case_item1; case_item2; case_item3; endcase // D: // time value1 value2 // xxxx xxxx // 1 0000 // 2 0000 // 3 0001 // 4 0001 // 5 0010 // 6 0010 module main ; reg [3:0] value1,value2,value3; initial begin #1 ; #2 if (value2 != 0) begin $display("FAILED == at time 3, %b != 0", value2); $finish; end #2 if (value2 != 1) begin $display("FAILED == at time 5, %b != 1", value2); $finish; end #2 if (value2 != 2) begin $display("FAILED == at time 7, %b != 2", value2); $finish; end $display("PASSED"); $finish; end initial begin #1 value1 = 4'b0000; #2 value1 = 4'b0001; #2 value1 = 4'b0010; end always case (value1) 4'b0000 : begin value2 = 4'b0000 ; #2 ; end 4'b0001 : begin value2 = 4'b0001 ; #2 ; end 4'b0010 : begin value2 = 4'b0010 ; #2 ; end 4'bxxxx : #2 ; default : begin $display("FAILED -- unexpected value1===%b", value1); $finish; end endcase endmodule