File: t_math_cmp.v

package info (click to toggle)
verilator 4.038-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 29,596 kB
  • sloc: cpp: 90,585; perl: 15,101; ansic: 8,573; yacc: 3,626; lex: 1,616; makefile: 1,101; sh: 175; python: 145
file content (167 lines) | stat: -rw-r--r-- 4,436 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2004 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0

module t (/*AUTOARG*/
   // Inputs
   clk
   );

   input clk;

   reg [2:0] index_a;
   reg [2:0] index_b;

   prover #(4)    p4  (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));
   prover #(32)  p32  (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));
   prover #(63)  p63  (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));
   prover #(64)  p64  (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));
   prover #(72)  p72  (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));
   prover #(126) p126 (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));
   prover #(128) p128 (/*AUTOINST*/
		       // Inputs
		       .clk		(clk),
		       .index_a		(index_a),
		       .index_b		(index_b));

   integer cyc; initial cyc=0;
   initial index_a = 3'b0;
   initial index_b = 3'b0;
   always @* begin
      index_a = cyc[2:0];  if (index_a>3'd4) index_a=3'd4;
      index_b = cyc[5:3];  if (index_b>3'd4) index_b=3'd4;
   end

   always @ (posedge clk) begin
      cyc <= cyc + 1;
      if (cyc==99) begin
	 $write("*-* All Finished *-*\n");
	 $finish;
      end
   end

endmodule


module prover (
   input       clk,
   input [2:0] index_a,
   input [2:0] index_b
   );

   parameter WIDTH = 4;


   reg signed [WIDTH-1:0] as;
   reg signed [WIDTH-1:0] bs;
   wire [WIDTH-1:0] 	  b = bs;

   always @* begin
      casez (index_a)
	 3'd0: as = {(WIDTH){1'd0}}; // 0
	 3'd1: as = {{(WIDTH-1){1'd0}}, 1'b1}; // 1
	 3'd2: as = {1'b0, {(WIDTH-1){1'd0}}}; // 127 or equiv
	 3'd3: as = {(WIDTH){1'd1}}; // -1
	 3'd4: as = {1'b1, {(WIDTH-1){1'd0}}}; // -128 or equiv
	 default: $stop;
      endcase
      casez (index_b)
	 3'd0: bs = {(WIDTH){1'd0}}; // 0
	 3'd1: bs = {{(WIDTH-1){1'd0}}, 1'b1}; // 1
	 3'd2: bs = {1'b0, {(WIDTH-1){1'd0}}}; // 127 or equiv
	 3'd3: bs = {(WIDTH){1'd1}}; // -1
	 3'd4: bs = {1'b1, {(WIDTH-1){1'd0}}}; // -128 or equiv
	 default: $stop;
      endcase
   end

   reg [7:0] results[4:0][4:0];

   wire gt   = as>b;
   wire gts  = as>bs;
   wire gte  = as>=b;
   wire gtes = as>=bs;
   wire lt   = as<b;
   wire lts  = as<bs;
   wire lte  = as<=b;
   wire ltes = as<=bs;

   reg [7:0] exp;
   reg [7:0] got;

   integer   cyc=0;
   always @ (posedge clk) begin
      cyc <= cyc + 1;
      if (cyc>2) begin
`ifdef TEST_VERBOSE
	 $write("results[%d][%d] = 8'b%b_%b_%b_%b_%b_%b_%b_%b;\n",
      		index_a, index_b,
      		gt, gts, gte, gtes, lt, lts, lte, ltes);
`endif
	 exp = results[index_a][index_b];
	 got   = {gt, gts, gte, gtes, lt, lts, lte, ltes};
	 if (exp !== got) begin
	    $display("%%Error: bad comparison width=%0d: %d/%d got=%b exp=%b", WIDTH, index_a,index_b,got, exp);
	    $stop;
	 end
      end
   end

   // Result table
   initial begin
      // Indexes: 0, 1, -1, 127, -128
      //                 Gt Gts Gte Gtes Lt Lts Lte Ltes
      results[0][0] = 8'b0_0_1_1_0_0_1_1;
      results[0][1] = 8'b0_0_0_0_1_1_1_1;
      results[0][2] = 8'b0_0_1_1_0_0_1_1;
      results[0][3] = 8'b0_1_0_1_1_0_1_0;
      results[0][4] = 8'b0_1_0_1_1_0_1_0;
      results[1][0] = 8'b1_1_1_1_0_0_0_0;
      results[1][1] = 8'b0_0_1_1_0_0_1_1;
      results[1][2] = 8'b1_1_1_1_0_0_0_0;
      results[1][3] = 8'b0_1_0_1_1_0_1_0;
      results[1][4] = 8'b0_1_0_1_1_0_1_0;
      results[2][0] = 8'b0_0_1_1_0_0_1_1;
      results[2][1] = 8'b0_0_0_0_1_1_1_1;
      results[2][2] = 8'b0_0_1_1_0_0_1_1;
      results[2][3] = 8'b0_1_0_1_1_0_1_0;
      results[2][4] = 8'b0_1_0_1_1_0_1_0;
      results[3][0] = 8'b1_0_1_0_0_1_0_1;
      results[3][1] = 8'b1_0_1_0_0_1_0_1;
      results[3][2] = 8'b1_0_1_0_0_1_0_1;
      results[3][3] = 8'b0_0_1_1_0_0_1_1;
      results[3][4] = 8'b1_1_1_1_0_0_0_0;
      results[4][0] = 8'b1_0_1_0_0_1_0_1;
      results[4][1] = 8'b1_0_1_0_0_1_0_1;
      results[4][2] = 8'b1_0_1_0_0_1_0_1;
      results[4][3] = 8'b0_0_0_0_1_1_1_1;
      results[4][4] = 8'b0_0_1_1_0_0_1_1;
   end

endmodule