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
|
// DESCRIPTION: Verilator: Verilog Test module
// verilator lint_off WIDTH
// verilator lint_off VARHIDDEN
module t (
clk
);
input clk;
integer cyc=0;
reg [63:0] crc; initial crc = 64'h1;
chk chk (.clk (clk),
.rst_l (1'b1),
.expr (|crc)
);
always @ (posedge clk) begin
cyc <= cyc + 1;
crc <= {crc[62:0], crc[63]^crc[2]^crc[0]};
if (cyc==0) begin
crc <= 64'h5aef0c8d_d70a4497;
end
else if (cyc<90) begin
end
else if (cyc==99) begin
$write("*-* All Finished *-*\n");
$finish;
end
end
endmodule
module chk (input clk, input rst_l, input expr);
integer errors; initial errors = 0;
task printerr;
input [8*64:1] msg;
begin
errors = errors + 1;
$write("%%Error: %0s\n", msg);
$stop;
end
endtask
always @(posedge clk) begin
if (rst_l) begin
if (expr == 1'b0) begin
printerr("expr not asserted");
end
end
end
wire noxs = ((expr ^ expr) == 1'b0);
reg hasx;
always @ (noxs) begin
if (noxs) begin
hasx = 1'b0;
end
else begin
hasx = 1'b1;
end
end
always @(posedge clk) begin
if (rst_l) begin
if (hasx) begin
printerr("expr has unknowns");
end
end
end
endmodule
|
