verilator/test_regress/t/t_randomize_dist_implication.v

85 lines
2.0 KiB
Systemverilog

// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain.
// SPDX-FileCopyrightText: 2026 PlanV GmbH
// SPDX-License-Identifier: CC0-1.0
// verilog_format: off
`define stop $stop
`define checkd(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d: got=%0d exp=%0d\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
// verilog_format: on
class DistScalar;
rand bit [7:0] x;
rand bit mode;
rand bit [1:0] mode2;
constraint force_cond { mode == 1'b0; mode2 == 2'b00; }
constraint c {
if (mode) {
x dist { 8'd0 := 1, 8'd255 := 3 };
} else {
(mode2 == '0) -> x dist { 8'd0 := 3, 8'd255 := 1 };
}
}
endclass
class DistChain;
rand bit [7:0] x;
rand bit a;
rand bit b;
constraint force_ab { a == 1'b1; b == 1'b1; }
constraint c {
a -> b -> x dist { 8'd0 := 3, 8'd255 := 1 };
}
endclass
class DistForeachImpl;
rand bit [7:0] arr [4];
rand bit enb;
constraint force_enb { enb == 1'b1; }
constraint c {
foreach (arr[i]) {
enb -> arr[i] dist { 8'd10 := 1, 8'd20 := 1, 8'd30 := 1 };
}
}
endclass
module t;
DistScalar obj;
DistChain ch;
DistForeachImpl fa;
initial begin
int p;
obj = new;
ch = new;
fa = new;
repeat (20) begin
p = obj.randomize();
`checkd(p, 1);
// Implication is forced to fire by force_cond; x must be a bucket value.
`checkd(obj.mode, 1'b0);
`checkd(obj.mode2, 2'b00);
`checkd((obj.x == 8'd0) || (obj.x == 8'd255), 1'b1);
p = ch.randomize();
`checkd(p, 1);
`checkd(ch.a, 1'b1);
`checkd(ch.b, 1'b1);
`checkd((ch.x == 8'd0) || (ch.x == 8'd255), 1'b1);
p = fa.randomize();
`checkd(p, 1);
`checkd(fa.enb, 1'b1);
foreach (fa.arr[i]) begin
`checkd((fa.arr[i] == 8'd10) || (fa.arr[i] == 8'd20)
|| (fa.arr[i] == 8'd30), 1'b1);
end
end
$write("*-* All Finished *-*\n");
$finish;
end
endmodule