42 lines
507 B
Coq
42 lines
507 B
Coq
|
primitive latch(q, e, d);
|
||
|
|
|
||
|
|
output q;
|
||
|
|
input e;
|
||
|
|
input d;
|
||
|
|
|
||
|
|
reg q;
|
||
|
|
|
||
|
|
table
|
||
|
|
// e d | q | q+ |
|
||
|
|
1 1 : ? : 1 ;
|
||
|
|
1 0 : ? : 0 ;
|
||
|
|
0 ? : ? : - ;
|
||
|
|
endtable
|
||
|
|
|
||
|
|
endprimitive
|
||
|
|
|
||
|
|
module test();
|
||
|
|
|
||
|
|
wire q;
|
||
|
|
reg e;
|
||
|
|
reg d;
|
||
|
|
reg r;
|
||
|
|
|
||
|
|
latch latch(q, e, d);
|
||
|
|
|
||
|
|
always @(q) begin
|
||
|
|
r = 1;
|
||
|
|
end
|
||
|
|
|
||
|
|
initial begin
|
||
|
|
#1;
|
||
|
|
$display("%b %b", q, r);
|
||
|
|
// the 'x' should propagate to q before the start of simulation
|
||
|
|
if (r === 1'bx && q === 1'bx)
|
||
|
|
$display("PASSED");
|
||
|
|
else
|
||
|
|
$display("FAILED");
|
||
|
|
end
|
||
|
|
|
||
|
|
endmodule
|