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// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2005 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0
module t (clk);
input clk;
reg [0:0] d1;
reg [2:0] d3;
reg [7:0] d8;
wire [0:0] q1;
wire [2:0] q3;
wire [7:0] q8;
reg ena;
condff #(12) condff
(.clk(clk), .sen(1'b0), .ena(ena),
.d({d8,d3,d1}),
.q({q8,q3,q1}));
integer cyc; initial cyc=1;
always @ (posedge clk) begin
if (cyc!=0) begin
//$write("%x %x %x %x\n", cyc, q8, q3, q1);
cyc <= cyc + 1;
if (cyc==1) begin
d1 <= 1'b1; d3<=3'h1; d8<=8'h11;
ena <= 1'b1;
end
if (cyc==2) begin
d1 <= 1'b0; d3<=3'h2; d8<=8'h33;
ena <= 1'b0;
end
if (cyc==3) begin
d1 <= 1'b1; d3<=3'h3; d8<=8'h44;
ena <= 1'b1;
if (q8 != 8'h11) $stop;
end
if (cyc==4) begin
d1 <= 1'b1; d3<=3'h4; d8<=8'h77;
ena <= 1'b1;
if (q8 != 8'h11) $stop;
end
if (cyc==5) begin
d1 <= 1'b1; d3<=3'h0; d8<=8'h88;
ena <= 1'b1;
if (q8 != 8'h44) $stop;
end
if (cyc==6) begin
if (q8 != 8'h77) $stop;
end
if (cyc==7) begin
if (q8 != 8'h88) $stop;
end
//
if (cyc==20) begin
$write("*-* All Finished *-*\n");
$finish;
end
end
end
endmodule
module condff (clk, sen, ena, d, q);
parameter WIDTH = 1;
input clk;
input sen;
input ena;
input [WIDTH-1:0] d;
output [WIDTH-1:0] q;
condffimp #(.WIDTH(WIDTH))
imp (.clk(clk), .sen(sen), .ena(ena), .d(d), .q(q));
endmodule
module condffimp (clk, sen, ena, d, q);
parameter WIDTH = 1;
input clk;
input sen;
input ena;
input [WIDTH-1:0] d;
output reg [WIDTH-1:0] q;
wire gatedclk;
clockgate clockgate (.clk(clk), .sen(sen), .ena(ena), .gatedclk(gatedclk));
always @(posedge gatedclk) begin
if (gatedclk === 1'bX) begin
q <= {WIDTH{1'bX}};
end
else begin
q <= d;
end
end
endmodule
module clockgate (clk, sen, ena, gatedclk);
input clk;
input sen;
input ena;
output gatedclk;
reg ena_b;
wire gatedclk = clk & ena_b;
// verilator lint_off COMBDLY
// verilator lint_off LATCH
always @(clk or ena or sen) begin
if (~clk) begin
ena_b <= ena | sen;
end
else begin
if ((clk^sen)===1'bX) ena_b <= 1'bX;
end
end
// verilator lint_on LATCH
// verilator lint_on COMBDLY
endmodule
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