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
|
// 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
);
input clk;
integer cyc; initial cyc=1;
// Life analysis checks
reg [15:0] life;
// Ding case
reg [7:0] din;
reg [15:0] fixin;
always @* begin
fixin = {din[7:0],din[7:0]};
case (din[1:0])
2'b00: begin
fixin = {fixin[14:0], 1'b1};
if (cyc==101) $display("Prevent ?: optimization a");
end
2'b01: begin
fixin = {fixin[13:0], 2'b11};
if (cyc==101) $display("Prevent ?: optimization b");
end
2'b10: begin
fixin = {fixin[12:0], 3'b111};
if (cyc==101) $display("Prevent ?: optimization c");
end
2'b11: begin
fixin = {fixin[11:0], 4'b1111};
if (cyc==101) $display("Prevent ?: optimization d");
end
endcase
end
always @ (posedge clk) begin
if (cyc!=0) begin
cyc<=cyc+1;
if (cyc==1) begin
life = 16'h8000; // Dropped
life = 16'h0010; // Used below
if (life != 16'h0010) $stop;
//
life = 16'h0020; // Used below
if ($time < 10000)
if (life != 16'h0020) $stop;
//
life = 16'h8000; // Dropped
if ($time > 100000) begin
if ($time != 0) $stop; // Prevent conversion to ?:
life = 16'h1030;
end
else
life = 16'h0030;
if (life != 16'h0030) $stop;
//
life = 16'h0040; // Not dropped, no else below
if ($time > 100000)
life = 16'h1040;
if (life != 16'h0040) $stop;
//
life = 16'h8000; // Dropped
if ($time > 100000) begin
life = 16'h1050;
if (life != 0) $stop; // Ignored, as set is first
end
else begin
if ($time > 100010)
life = 16'h1050;
else life = 16'h0050;
end
if (life != 16'h0050) $stop;
end
if (cyc==2) begin
din <= 8'haa;
end
if (cyc==3) begin
din <= 8'hfb;
if (fixin != 16'h5557) $stop;
end
if (cyc==4) begin
din <= 8'h5c;
if (fixin != 16'hbfbf) $stop;
end
if (cyc==5) begin
din <= 8'hed;
if (fixin != 16'hb8b9) $stop;
end
if (cyc==6) begin
if (fixin != 16'hb7b7) $stop;
end
if (cyc==9) begin
$write("*-* All Finished *-*\n");
$finish;
end
end
end
endmodule
|
