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8bitworkshop/test/cli/verilog/t_func_grey.v
2021-07-06 22:26:29 -05:00

73 lines
1.5 KiB
Verilog

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2003 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0
module t (/*AUTOARG*/
// Inputs
clk
);
// surefire lint_off _NETNM
// surefire lint_off STMINI
input clk;
integer _mode; initial _mode = 0;
wire [2:0] b3; reg [2:0] g3;
wire [5:0] b6; reg [5:0] g6;
t_func_grey2bin #(3) g2b3 (.b(b3), .g(g3));
t_func_grey2bin #(6) g2b6 (.b(b6), .g(g6));
always @ (posedge clk) begin
if (_mode==0) begin
_mode <= 1;
g3 <= 3'b101;
g6 <= 6'b110101;
end
else if (_mode==1) begin
if (b3 !== 3'b110) $stop;
if (b6 !== 6'b100110) $stop;
_mode <= 2;
$write("*-* All Finished *-*\n");
$finish;
end
end
endmodule
// Module gray2bin
// convert an arbitrary width gray coded number to binary. The conversion
// of a 4 bit gray (represented as "g") to binary ("b") would go as follows:
// b[3] = ^g[3] = g[3]
// b[2] = ^g[3:2]
// b[1] = ^g[3:1]
// b[0] = ^g[3:[SZ-1:0] cur0]
module t_func_grey2bin (/*AUTOARG*/
// Outputs
b,
// Inputs
g
);
// surefire lint_off STMFOR
parameter SZ = 5;
output [SZ-1:0] b;
input [SZ-1:0] g;
/*AUTOREG*/
// Beginning of automatic regs (for this module's undeclared outputs)
reg [SZ-1:0] b;
// End of automatics
integer i;
always @(/*AUTOSENSE*/g)
for (i=0; i<SZ; i=i+1)
b[i] = ^(g >> i); // surefire lint_off_line LATASS
endmodule