Prompt:
module top_module(
	input a,
	input b,
	output out
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input a,
	input b,
	output out
);

	assign out = a & b;

endmodule

module stimulus_gen (
	input clk,
	output reg a, b,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		int count; count = 0;
		{a,b} <= 1'b0;
		wavedrom_start("AND gate");
		repeat(10) @(posedge clk)
			{a,b} <= count++;
		wavedrom_stop();

		repeat(200) @(posedge clk, negedge clk)
			{b,a} <= $random;

		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_out;
		int errortime_out;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic out_ref;
	logic out_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,out_ref,out_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b );
	reference_module good1 (
		.a,
		.b,
		.out(out_ref) );

	top_module top_module1 (
		.a,
		.b,
		.out(out_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_out) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "out", stats1.errors_out, stats1.errortime_out);
		else $display("Hint: Output '%s' has no mismatches.", "out");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { out_ref } === ( { out_ref } ^ { out_dut } ^ { out_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (out_ref !== ( out_ref ^ out_dut ^ out_ref ))
		begin if (stats1.errors_out == 0) stats1.errortime_out = $time;
			stats1.errors_out = stats1.errors_out+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input [7:0] code,
	output reg [3:0] out,
	output reg valid
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input [7:0] code,
	output reg [3:0] out,
	output reg valid
);
//	uhh.. make a case statement: maps scancode to 0-9, but accidentally infer a latch?
//  and have one of the entries be wrong? (duplicate case, using different base!)
	always @(*) begin
		out = 0;
		valid = 1;
		case (code)
			8'h45: out = 0;
			8'h16: out = 1;
			8'h1e: out = 2;
			8'h26: out = 3;
			8'h25: out = 4;
			8'h2e: out = 5;
			8'h36: out = 6;
			8'h3d: out = 7;
			8'h3e: out = 8;
			8'h46: out = 9;
			default: valid = 0;
		endcase
	end

endmodule

module stimulus_gen (
	input clk,
	output logic [7:0] code,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	input tb_match
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		code <= 8'h45;
		@(negedge clk) wavedrom_start("Decode scancodes");
			@(posedge clk) code <= 8'h45;
			@(posedge clk) code <= 8'h03;
			@(posedge clk) code <= 8'h46;
			@(posedge clk) code <= 8'h16;
			@(posedge clk) code <= 8'd26;
			@(posedge clk) code <= 8'h1e;
			@(posedge clk) code <= 8'h25;
			@(posedge clk) code <= 8'h26;
			@(posedge clk) code <= 8'h2e;
			@(posedge clk) code <= $random;
			@(posedge clk) code <= 8'h36;
			@(posedge clk) code <= $random;
			@(posedge clk) code <= 8'h3d;
			@(posedge clk) code <= 8'h3e;
			@(posedge clk) code <= 8'h45;
			@(posedge clk) code <= 8'h46;
			@(posedge clk) code <= $random;
			@(posedge clk) code <= $random;
			@(posedge clk) code <= $random;
			@(posedge clk) code <= $random;
		wavedrom_stop();

		repeat(1000) @(posedge clk, negedge clk) begin
			code <= $urandom;
		end

		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_out;
		int errortime_out;
		int errors_valid;
		int errortime_valid;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic [7:0] code;
	logic [3:0] out_ref;
	logic [3:0] out_dut;
	logic valid_ref;
	logic valid_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,code,out_ref,out_dut,valid_ref,valid_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.code );
	reference_module good1 (
		.code,
		.out(out_ref),
		.valid(valid_ref) );

	top_module top_module1 (
		.code,
		.out(out_dut),
		.valid(valid_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_out) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "out", stats1.errors_out, stats1.errortime_out);
		else $display("Hint: Output '%s' has no mismatches.", "out");
		if (stats1.errors_valid) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "valid", stats1.errors_valid, stats1.errortime_valid);
		else $display("Hint: Output '%s' has no mismatches.", "valid");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { out_ref, valid_ref } === ( { out_ref, valid_ref } ^ { out_dut, valid_dut } ^ { out_ref, valid_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (out_ref !== ( out_ref ^ out_dut ^ out_ref ))
		begin if (stats1.errors_out == 0) stats1.errortime_out = $time;
			stats1.errors_out = stats1.errors_out+1'b1; end
		if (valid_ref !== ( valid_ref ^ valid_dut ^ valid_ref ))
		begin if (stats1.errors_valid == 0) stats1.errortime_valid = $time;
			stats1.errors_valid = stats1.errors_valid+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input sel,
	input [7:0] a,
	input [7:0] b,
	output reg [7:0] out
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input sel,
	input [7:0] a,
	input [7:0] b,
	output reg [7:0] out
);

	// assign out = (~sel & a) | (sel & b);
    assign out = sel ? a : b;

endmodule

module stimulus_gen (
	input clk,
	output logic sel,
	output logic [7:0] a, b,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		{a, b, sel} <= '0;
		@(negedge clk) wavedrom_start("");
			@(posedge clk, negedge clk) {a,b,sel} <= {8'haa, 8'hbb, 1'b0};
			@(posedge clk, negedge clk) {a,b,sel} <= {8'haa, 8'hbb, 1'b0};
			@(posedge clk, negedge clk) {a,b,sel} <= {8'haa, 8'hbb, 1'b1};
			@(posedge clk, negedge clk) {a,b,sel} <= {8'haa, 8'hbb, 1'b0};
			@(posedge clk, negedge clk) {a,b,sel} <= {8'haa, 8'hbb, 1'b1};
			@(posedge clk, negedge clk) {a,b,sel} <= {8'haa, 8'hbb, 1'b1};

			@(posedge clk, negedge clk) {a, b} <= {8'hff, 8'h00}; sel <= 1'b0;
			@(posedge clk, negedge clk) sel <= 1'b0;
			@(posedge clk, negedge clk) sel <= 1'b1;
			@(posedge clk, negedge clk) sel <= 1'b0;
			@(posedge clk, negedge clk) sel <= 1'b1;
			@(posedge clk, negedge clk) sel <= 1'b1;
		wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b,sel} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_out;
		int errortime_out;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic sel;
	logic [7:0] a;
	logic [7:0] b;
	logic [7:0] out_ref;
	logic [7:0] out_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,sel,a,b,out_ref,out_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.sel,
		.a,
		.b );
	reference_module good1 (
		.sel,
		.a,
		.b,
		.out(out_ref) );

	top_module top_module1 (
		.sel,
		.a,
		.b,
		.out(out_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_out) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "out", stats1.errors_out, stats1.errortime_out);
		else $display("Hint: Output '%s' has no mismatches.", "out");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { out_ref } === ( { out_ref } ^ { out_dut } ^ { out_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (out_ref !== ( out_ref ^ out_dut ^ out_ref ))
		begin if (stats1.errors_out == 0) stats1.errortime_out = $time;
			stats1.errors_out = stats1.errors_out+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input a,
	input b,
	output q
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input a,
	input b,
	output q
);

	assign q = a&b;

endmodule

module stimulus_gen (
	input clk,
	output logic a,b,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		{a,b} <= 0;
		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b} <= 0;
			repeat(8) @(posedge clk) {a,b} <= {a,b} + 1;
		@(negedge clk) wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic q_ref;
	logic q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b );
	reference_module good1 (
		.a,
		.b,
		.q(q_ref) );

	top_module top_module1 (
		.a,
		.b,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input clk,
	input a,
	input b,
	output q,
	output state
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input clk,
	input a,
	input b,
	output q,
	output state
);

	reg c;
	always @(posedge clk)
		c <= a&b | a&c | b&c;

	assign q = a^b^c;
	assign state = c;

endmodule

module stimulus_gen (
	input clk,
	output logic a,
	output logic b,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		a <= 1;
		@(negedge clk) {a,b} <= 0;
		@(negedge clk) wavedrom_start("Unknown circuit");
			repeat(3) @(posedge clk);
			{a,b} <= 1;
			@(posedge clk) {a,b} <= 2;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 0;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 2;
			@(posedge clk) {a,b} <= 1;
			@(posedge clk) {a,b} <= 0;
			@(posedge clk) {a,b} <= 0;
			@(posedge clk) {a,b} <= 0;
			@(negedge clk);
		wavedrom_stop();

		repeat(200) @(posedge clk, negedge clk)
			a <= &((5)'($urandom));
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;
		int errors_state;
		int errortime_state;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic q_ref;
	logic q_dut;
	logic state_ref;
	logic state_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,a,b,q_ref,q_dut,state_ref,state_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b );
	reference_module good1 (
		.clk,
		.a,
		.b,
		.q(q_ref),
		.state(state_ref) );

	top_module top_module1 (
		.clk,
		.a,
		.b,
		.q(q_dut),
		.state(state_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");
		if (stats1.errors_state) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "state", stats1.errors_state, stats1.errortime_state);
		else $display("Hint: Output '%s' has no mismatches.", "state");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref, state_ref } === ( { q_ref, state_ref } ^ { q_dut, state_dut } ^ { q_ref, state_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end
		if (state_ref !== ( state_ref ^ state_dut ^ state_ref ))
		begin if (stats1.errors_state == 0) stats1.errortime_state = $time;
			stats1.errors_state = stats1.errors_state+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input clk,
	input a,
	input b,
	output q,
	output state
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input clk,
	input a,
	input b,
	output q,
	output state
);

	reg c;
	always @(posedge clk)
		c <= a&b | a&c | b&c;

	assign q = a^b^c;
	assign state = c;

endmodule

module stimulus_gen (
	input clk,
	output logic a,
	output logic b,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		a <= 1;
		@(negedge clk) {a,b} <= 0;
		@(negedge clk) wavedrom_start("Unknown circuit");
			repeat(3) @(posedge clk);
			{a,b} <= 1;
			@(posedge clk) {a,b} <= 2;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 0;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 3;
			@(posedge clk) {a,b} <= 2;
			@(posedge clk) {a,b} <= 1;
			@(posedge clk) {a,b} <= 0;
			@(posedge clk) {a,b} <= 0;
			@(posedge clk) {a,b} <= 0;
			@(negedge clk);
		wavedrom_stop();

		repeat(200) @(posedge clk, negedge clk)
			a <= &((5)'($urandom));
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;
		int errors_state;
		int errortime_state;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic q_ref;
	logic q_dut;
	logic state_ref;
	logic state_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,a,b,q_ref,q_dut,state_ref,state_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b );
	reference_module good1 (
		.clk,
		.a,
		.b,
		.q(q_ref),
		.state(state_ref) );

	top_module top_module1 (
		.clk,
		.a,
		.b,
		.q(q_dut),
		.state(state_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");
		if (stats1.errors_state) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "state", stats1.errors_state, stats1.errortime_state);
		else $display("Hint: Output '%s' has no mismatches.", "state");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref, state_ref } === ( { q_ref, state_ref } ^ { q_dut, state_dut } ^ { q_ref, state_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end
		if (state_ref !== ( state_ref ^ state_dut ^ state_ref ))
		begin if (stats1.errors_state == 0) stats1.errortime_state = $time;
			stats1.errors_state = stats1.errors_state+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input a,
	input b,
	input c,
	input d,
	output q
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input a,
	input b,
	input c,
	input d,
	output q
);

	assign q = (a|b) & (c|d);

endmodule

module stimulus_gen (
	input clk,
	output logic a,b,c,d,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		{a,b,c,d} <= 0;
		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d} <= 0;
			repeat(18) @(posedge clk, negedge clk) {a,b,c,d} <= {a,b,c,d} + 1;
		wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b,c,d} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic c;
	logic d;
	logic q_ref;
	logic q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,c,d,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b,
		.c,
		.d );
	reference_module good1 (
		.a,
		.b,
		.c,
		.d,
		.q(q_ref) );

	top_module top_module1 (
		.a,
		.b,
		.c,
		.d,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input a,
	input b,
	input c,
	input d,
	output q
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input a,
	input b,
	input c,
	input d,
	output q
);

	assign q = c | b;

endmodule

module stimulus_gen (
	input clk,
	output logic a,b,c,d,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		{a,b,c,d} <= 0;
		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d} <= 0;
			repeat(18) @(posedge clk, negedge clk) {a,b,c,d} <= {a,b,c,d} + 1;
		wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b,c,d} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic c;
	logic d;
	logic q_ref;
	logic q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,c,d,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b,
		.c,
		.d );
	reference_module good1 (
		.a,
		.b,
		.c,
		.d,
		.q(q_ref) );

	top_module top_module1 (
		.a,
		.b,
		.c,
		.d,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input a,
	input b,
	input c,
	input d,
	output q
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input a,
	input b,
	input c,
	input d,
	output q
);

	assign q = c | b;

endmodule

module stimulus_gen (
	input clk,
	output logic a,b,c,d,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		{a,b,c,d} <= 0;
		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d} <= 0;
			repeat(18) @(posedge clk, negedge clk) {a,b,c,d} <= {a,b,c,d} + 1;
		wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b,c,d} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic a;
	logic b;
	logic c;
	logic d;
	logic q_ref;
	logic q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,c,d,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b,
		.c,
		.d );
	reference_module good1 (
		.a,
		.b,
		.c,
		.d,
		.q(q_ref) );

	top_module top_module1 (
		.a,
		.b,
		.c,
		.d,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input [3:0] a,
	input [3:0] b,
	input [3:0] c,
	input [3:0] d,
	input [3:0] e,
	output reg [3:0] q
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input [3:0] a,
	input [3:0] b,
	input [3:0] c,
	input [3:0] d,
	input [3:0] e,
	output reg [3:0] q
);

	always @(*)
		case (c)
			0: q = b;
			1: q = e;
			2: q = a;
			3: q = d;
			default: q = 4'hf;
		endcase

endmodule

module stimulus_gen (
	input clk,
	output logic [3:0] a,b,c,d,e,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d,e} <= {20'hab0de};
			repeat(18) @(posedge clk, negedge clk) c <= c + 1;
		wavedrom_stop();

		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d,e} <= {20'h12034};
			repeat(8) @(posedge clk, negedge clk) c <= c + 1;
			@(posedge clk) {a,b,c,d,e} <= {20'h56078};
			repeat(8) @(posedge clk, negedge clk) c <= c + 1;
		wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b,c,d,e} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic [3:0] a;
	logic [3:0] b;
	logic [3:0] c;
	logic [3:0] d;
	logic [3:0] e;
	logic [3:0] q_ref;
	logic [3:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,c,d,e,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b,
		.c,
		.d,
		.e );
	reference_module good1 (
		.a,
		.b,
		.c,
		.d,
		.e,
		.q(q_ref) );

	top_module top_module1 (
		.a,
		.b,
		.c,
		.d,
		.e,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module (
	input [3:0] a,
	input [3:0] b,
	input [3:0] c,
	input [3:0] d,
	input [3:0] e,
	output reg [3:0] q
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module (
	input [3:0] a,
	input [3:0] b,
	input [3:0] c,
	input [3:0] d,
	input [3:0] e,
	output reg [3:0] q
);

	always @(*)
		case (c)
			0: q = b;
			1: q = e;
			2: q = a;
			3: q = d;
			default: q = 4'hf;
		endcase

endmodule

module stimulus_gen (
	input clk,
	output logic [3:0] a,b,c,d,e,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d,e} <= {20'hab0de};
			repeat(18) @(posedge clk, negedge clk) c <= c + 1;
		wavedrom_stop();

		@(negedge clk) wavedrom_start("Unknown circuit");
			@(posedge clk) {a,b,c,d,e} <= {20'h12034};
			repeat(8) @(posedge clk, negedge clk) c <= c + 1;
			@(posedge clk) {a,b,c,d,e} <= {20'h56078};
			repeat(8) @(posedge clk, negedge clk) c <= c + 1;
		wavedrom_stop();

		repeat(100) @(posedge clk, negedge clk)
			{a,b,c,d,e} <= $urandom;
		$finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic [3:0] a;
	logic [3:0] b;
	logic [3:0] c;
	logic [3:0] d;
	logic [3:0] e;
	logic [3:0] q_ref;
	logic [3:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,a,b,c,d,e,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.a,
		.b,
		.c,
		.d,
		.e );
	reference_module good1 (
		.a,
		.b,
		.c,
		.d,
		.e,
		.q(q_ref) );

	top_module top_module1 (
		.a,
		.b,
		.c,
		.d,
		.e,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input load,
	input [255:0] data,
	output reg [255:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input load,
	input [255:0] data,
	output reg [255:0] q);

	logic [323:0] q_pad;
	always@(*) begin
		for (int i=0;i<16;i++)
			q_pad[18*(i+1)+1 +: 16] = q[16*i +: 16];
		q_pad[1 +: 16] = q[16*15 +: 16];
		q_pad[18*17+1 +: 16] = q[0 +: 16];

		for (int i=0; i<18; i++) begin
			q_pad[i*18] = q_pad[i*18+16];
			q_pad[i*18+17] = q_pad[i*18+1];
		end
	end

	always @(posedge clk) begin
		for (int i=0;i<16;i++)
		for (int j=0;j<16;j++) begin
			q[i*16+j] <=
				((q_pad[(i+1)*18+j+1 -1+18] + q_pad[(i+1)*18+j+1 +18] + q_pad[(i+1)*18+j+1 +1+18] +
				q_pad[(i+1)*18+j+1 -1]                                + q_pad[(i+1)*18+j+1+1] +
				q_pad[(i+1)*18+j+1 -1-18]   + q_pad[(i+1)*18+j+1 -18] + q_pad[(i+1)*18+j+1 +1-18]) & 3'h7 | q[i*16+j]) == 3'h3;
		end

		if (load)
			q <= data;

	end

endmodule

module stimulus_gen (
	input clk,
	input tb_match,
	input [255:0] q_ref,
	input [255:0] q_dut,
	output reg load,
	output reg[255:0] data
);

	logic errored = 0;
	int blinker_cycle = 0;

	initial begin
		data <= 3'h7;			// Simple blinker, period 2
		load <= 1;
		@(posedge clk);
		load <= 0;
		data <= 4'hx;
		errored = 0;
		blinker_cycle = 0;
		repeat(5) @(posedge clk) begin
			blinker_cycle++;
			if (!tb_match) begin
				if (!errored) begin
					errored = 1;
					$display("Hint: The first test case is a blinker (initial state = 256'h7). First mismatch occurred at cycle %0d.\nHint:", blinker_cycle);
				end
			end

			if (errored) begin
				$display ("Hint: Cycle %0d:         Your game state       Reference game state", blinker_cycle);
				for (int i=15;i>=0;i--) begin
					$display("Hint:   q[%3d:%3d]     %016b      %016b", i*16+15, i*16, q_dut [ i*16 +: 16 ], q_ref[ i*16 +: 16 ]);
				end
				$display("Hint:\nHint:\n");
			end
		end

		data <= 48'h000200010007;	// Glider, Traveling diagonal down-right.
		load <= 1;
		@(posedge clk);
		@(posedge clk);
		@(posedge clk);
		load <= 0;
		data <= 4'hx;
		errored = 0;
		blinker_cycle = 0;
		repeat(100) @(posedge clk) begin
			blinker_cycle++;
			if (!tb_match) begin
				if (!errored) begin
					errored = 1;
					$display("Hint: The second test case is a glider (initial state = 256'h000200010007). First mismatch occurred at cycle %0d.\nHint:", blinker_cycle);
				end
			end

			if (errored && blinker_cycle < 20) begin
				$display ("Hint: Cycle %0d:         Your game state       Reference game state", blinker_cycle);
				for (int i=15;i>=0;i--) begin
					$display("Hint:   q[%3d:%3d]     %016b      %016b", i*16+15, i*16, q_dut [ i*16 +: 16 ], q_ref[ i*16 +: 16 ]);
				end
				$display("Hint:\nHint:\n");
			end
		end

		data <= 48'h0040001000ce;			// Acorn
		load <= 1;
		@(posedge clk);
		load <= 0;
		repeat(2000) @(posedge clk);

		data <= {$random,$random,$random,$random,$random,$random,$random,$random};		// Some random test cases.
		load <= 1;
		@(posedge clk);
		load <= 0;
		repeat(200) @(posedge clk);

		data <= {$random,$random,$random,$random,$random,$random,$random,$random}&		// Random with more zeros.
				{$random,$random,$random,$random,$random,$random,$random,$random}&
				{$random,$random,$random,$random,$random,$random,$random,$random}&
				{$random,$random,$random,$random,$random,$random,$random,$random};
		load <= 1;
		@(posedge clk);
		load <= 0;
		repeat(200) @(posedge clk);

		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic load;
	logic [255:0] data;
	logic [255:0] q_ref;
	logic [255:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,load,data,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.load,
		.data );
	reference_module good1 (
		.clk,
		.load,
		.data,
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.load,
		.data,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input load,
	input [255:0] data,
	output reg [255:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input load,
	input [255:0] data,
	output reg [255:0] q);

	logic [323:0] q_pad;
	always@(*) begin
		for (int i=0;i<16;i++)
			q_pad[18*(i+1)+1 +: 16] = q[16*i +: 16];
		q_pad[1 +: 16] = q[16*15 +: 16];
		q_pad[18*17+1 +: 16] = q[0 +: 16];

		for (int i=0; i<18; i++) begin
			q_pad[i*18] = q_pad[i*18+16];
			q_pad[i*18+17] = q_pad[i*18+1];
		end
	end

	always @(posedge clk) begin
		for (int i=0;i<16;i++)
		for (int j=0;j<16;j++) begin
			q[i*16+j] <=
				((q_pad[(i+1)*18+j+1 -1+18] + q_pad[(i+1)*18+j+1 +18] + q_pad[(i+1)*18+j+1 +1+18] +
				q_pad[(i+1)*18+j+1 -1]                                + q_pad[(i+1)*18+j+1+1] +
				q_pad[(i+1)*18+j+1 -1-18]   + q_pad[(i+1)*18+j+1 -18] + q_pad[(i+1)*18+j+1 +1-18]) & 3'h7 | q[i*16+j]) == 3'h3;
		end

		if (load)
			q <= data;

	end

endmodule

module stimulus_gen (
	input clk,
	input tb_match,
	input [255:0] q_ref,
	input [255:0] q_dut,
	output reg load,
	output reg[255:0] data
);

	logic errored = 0;
	int blinker_cycle = 0;

	initial begin
		data <= 3'h7;			// Simple blinker, period 2
		load <= 1;
		@(posedge clk);
		load <= 0;
		data <= 4'hx;
		errored = 0;
		blinker_cycle = 0;
		repeat(5) @(posedge clk) begin
			blinker_cycle++;
			if (!tb_match) begin
				if (!errored) begin
					errored = 1;
					$display("Hint: The first test case is a blinker (initial state = 256'h7). First mismatch occurred at cycle %0d.\nHint:", blinker_cycle);
				end
			end

			if (errored) begin
				$display ("Hint: Cycle %0d:         Your game state       Reference game state", blinker_cycle);
				for (int i=15;i>=0;i--) begin
					$display("Hint:   q[%3d:%3d]     %016b      %016b", i*16+15, i*16, q_dut [ i*16 +: 16 ], q_ref[ i*16 +: 16 ]);
				end
				$display("Hint:\nHint:\n");
			end
		end

		data <= 48'h000200010007;	// Glider, Traveling diagonal down-right.
		load <= 1;
		@(posedge clk);
		@(posedge clk);
		@(posedge clk);
		load <= 0;
		data <= 4'hx;
		errored = 0;
		blinker_cycle = 0;
		repeat(100) @(posedge clk) begin
			blinker_cycle++;
			if (!tb_match) begin
				if (!errored) begin
					errored = 1;
					$display("Hint: The second test case is a glider (initial state = 256'h000200010007). First mismatch occurred at cycle %0d.\nHint:", blinker_cycle);
				end
			end

			if (errored && blinker_cycle < 20) begin
				$display ("Hint: Cycle %0d:         Your game state       Reference game state", blinker_cycle);
				for (int i=15;i>=0;i--) begin
					$display("Hint:   q[%3d:%3d]     %016b      %016b", i*16+15, i*16, q_dut [ i*16 +: 16 ], q_ref[ i*16 +: 16 ]);
				end
				$display("Hint:\nHint:\n");
			end
		end

		data <= 48'h0040001000ce;			// Acorn
		load <= 1;
		@(posedge clk);
		load <= 0;
		repeat(2000) @(posedge clk);

		data <= {$random,$random,$random,$random,$random,$random,$random,$random};		// Some random test cases.
		load <= 1;
		@(posedge clk);
		load <= 0;
		repeat(200) @(posedge clk);

		data <= {$random,$random,$random,$random,$random,$random,$random,$random}&		// Random with more zeros.
				{$random,$random,$random,$random,$random,$random,$random,$random}&
				{$random,$random,$random,$random,$random,$random,$random,$random}&
				{$random,$random,$random,$random,$random,$random,$random,$random};
		load <= 1;
		@(posedge clk);
		load <= 0;
		repeat(200) @(posedge clk);

		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic load;
	logic [255:0] data;
	logic [255:0] q_ref;
	logic [255:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,load,data,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.load,
		.data );
	reference_module good1 (
		.clk,
		.load,
		.data,
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.load,
		.data,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input reset,
	output reg [3:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input reset,
	output reg [3:0] q);

	always @(posedge clk)
		if (reset)
			q <= 0;
		else
			q <= q+1;

endmodule

module stimulus_gen (
	input clk,
	output reg reset,
	input tb_match,
	output reg wavedrom_enable,
	output reg[511:0] wavedrom_title
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

	initial begin
		reset <= 1;
		@(negedge clk);

		wavedrom_start("Reset and counting");
		reset_test();

		repeat(3) @(posedge clk);
		wavedrom_stop();

		repeat(400) @(posedge clk, negedge clk) begin
			reset <= !($random & 31);
		end
		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic reset;
	logic [3:0] q_ref;
	logic [3:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,reset,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.reset );
	reference_module good1 (
		.clk,
		.reset,
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.reset,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input reset,
	output reg [3:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input reset,
	output reg [3:0] q);

	always @(posedge clk)
		if (reset || q == 10)
			q <= 1;
		else
			q <= q+1;

endmodule

module stimulus_gen (
	input clk,
	output reg reset,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	input tb_match
);

	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		reset <= 1;
		wavedrom_start("Synchronous reset and counting.");
		reset_test();
		repeat(12) @(posedge clk);
		wavedrom_stop();
		@(posedge clk);

		repeat(400) @(posedge clk, negedge clk) begin
			reset <= !($random & 31);
		end
		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic reset;
	logic [3:0] q_ref;
	logic [3:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,reset,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.reset );
	reference_module good1 (
		.clk,
		.reset,
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.reset,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input reset,
	input ena,
	output reg pm,
	output reg [7:0] hh,
	output reg [7:0] mm,
	output reg [7:0] ss);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input reset,
	input ena,
	output reg pm,
	output reg [7:0] hh,
	output reg [7:0] mm,
	output reg [7:0] ss);

	wire [6:0] enable = {
		{hh[7:0],mm[7:0],ss[7:0]}==24'h115959,
		{hh[3:0],mm[7:0],ss[7:0]}==20'h95959,
		{mm[7:0],ss[7:0]}==16'h5959,
		{mm[3:0],ss[7:0]}==12'h959,
		ss[7:0]==8'h59,
		ss[3:0] == 4'h9,
		1'b1};

	always @(posedge clk)
		if (reset)
			{pm,hh,mm,ss} <= 25'h0120000;
		else if (ena) begin
			if (enable[0] && ss[3:0] == 9) ss[3:0] <= 0;
			else if (enable[0]) ss[3:0] <= ss[3:0] + 1;

			if (enable[1] && ss[7:4] == 4'h5) ss[7:4] <= 0;
			else if (enable[1]) ss[7:4] <= ss[7:4] + 1;

			if (enable[2] && mm[3:0] == 9) mm[3:0] <= 0;
			else if (enable[2]) mm[3:0] <= mm[3:0] + 1;

			if (enable[3] && mm[7:4] == 4'h5) mm[7:4] <= 0;
			else if (enable[3]) mm[7:4] <= mm[7:4] + 1;

			if (enable[4] && hh[3:0] == 4'h9) hh[3:0] <= 0;
			else if (enable[4]) hh[3:0] <= hh[3:0] + 1;

			if (enable[4] && hh[7:0] == 8'h12) hh[7:0] <= 8'h1;
			else if (enable[5]) hh[7:4] <= hh[7:4] + 1;

			if (enable[6]) pm <= ~pm;
		end
endmodule

module stimulus_gen (
	input clk,
	output reg reset,
	output reg ena,
	input [7:0] hh_dut, mm_dut, ss_dut,
	input pm_dut,
	input tb_match,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);
	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	logic bcd_fail = 0;
	logic reset_fail = 0;

	always @(posedge clk) begin
		if ((hh_dut[3:0] >= 4'ha) ||
			(hh_dut[7:4] >= 4'ha) ||
			(mm_dut[3:0] >= 4'ha) ||
			(mm_dut[7:4] >= 4'ha) ||
			(ss_dut[3:0] >= 4'ha) ||
			(ss_dut[7:4] >= 4'ha))
			bcd_fail <= 1'b1;
	end

	initial begin
		reset <= 1;
		ena <= 1;
		wavedrom_start("Reset and count to 10");
		reset_test();
		repeat(12) @(posedge clk);
		wavedrom_stop();
		ena <= 1'b1;
		reset <= 1'b1;
		@(posedge clk);
		@(posedge clk)
			if (!tb_match) begin
				$display("Hint: Clock seems to reset to %02x:%02x:%02x %s (Should be 12:00:00 AM).", hh_dut, mm_dut, ss_dut, pm_dut ? "PM": "AM");
				reset_fail <= 1'b1;
			end

		reset <= 1'b0;
		@(posedge clk);
		@(posedge clk);
		@(posedge clk);
		ena <= 1'b0;
		reset <= 1'b1;
		@(posedge clk);
		@(posedge clk)
			if (!tb_match && !reset_fail)
				$display("Hint: Reset has higher priority than enable and should occur even if not enabled.");

		repeat(400) @(posedge clk, negedge clk) begin
			reset <= !($random & 31);
			ena <= !($random & 3);
		end
		reset <= 1;
		@(posedge clk) begin
			{reset, ena} <= 2'b1;
		end

		repeat(55) @(posedge clk);
		wavedrom_start("Minute roll-over");
		repeat(10) @(posedge clk);
		wavedrom_stop();

		repeat(3530) @(posedge clk);
		wavedrom_start("Hour roll-over");
		repeat(10) @(posedge clk);
		wavedrom_stop();

		repeat(39590) @(posedge clk);
		wavedrom_start("PM roll-over");
		repeat(10) @(posedge clk);
		wavedrom_stop();

		repeat(132745) @(posedge clk);
		repeat(50) @(posedge clk, negedge clk) begin
			ena <= !($random & 7);
		end
		reset <= 1'b1;
		repeat(5) @(posedge clk);

		if (bcd_fail)
			$display("Hint: Non-BCD values detected. Are you sure you're using two-digit BCD representation for hh, mm, and ss?");

		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_pm;
		int errortime_pm;
		int errors_hh;
		int errortime_hh;
		int errors_mm;
		int errortime_mm;
		int errors_ss;
		int errortime_ss;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic reset;
	logic ena;
	logic pm_ref;
	logic pm_dut;
	logic [7:0] hh_ref;
	logic [7:0] hh_dut;
	logic [7:0] mm_ref;
	logic [7:0] mm_dut;
	logic [7:0] ss_ref;
	logic [7:0] ss_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,reset,ena,pm_ref,pm_dut,hh_ref,hh_dut,mm_ref,mm_dut,ss_ref,ss_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.reset,
		.ena );
	reference_module good1 (
		.clk,
		.reset,
		.ena,
		.pm(pm_ref),
		.hh(hh_ref),
		.mm(mm_ref),
		.ss(ss_ref) );

	top_module top_module1 (
		.clk,
		.reset,
		.ena,
		.pm(pm_dut),
		.hh(hh_dut),
		.mm(mm_dut),
		.ss(ss_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_pm) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "pm", stats1.errors_pm, stats1.errortime_pm);
		else $display("Hint: Output '%s' has no mismatches.", "pm");
		if (stats1.errors_hh) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "hh", stats1.errors_hh, stats1.errortime_hh);
		else $display("Hint: Output '%s' has no mismatches.", "hh");
		if (stats1.errors_mm) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "mm", stats1.errors_mm, stats1.errortime_mm);
		else $display("Hint: Output '%s' has no mismatches.", "mm");
		if (stats1.errors_ss) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "ss", stats1.errors_ss, stats1.errortime_ss);
		else $display("Hint: Output '%s' has no mismatches.", "ss");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { pm_ref, hh_ref, mm_ref, ss_ref } === ( { pm_ref, hh_ref, mm_ref, ss_ref } ^ { pm_dut, hh_dut, mm_dut, ss_dut } ^ { pm_ref, hh_ref, mm_ref, ss_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (pm_ref !== ( pm_ref ^ pm_dut ^ pm_ref ))
		begin if (stats1.errors_pm == 0) stats1.errortime_pm = $time;
			stats1.errors_pm = stats1.errors_pm+1'b1; end
		if (hh_ref !== ( hh_ref ^ hh_dut ^ hh_ref ))
		begin if (stats1.errors_hh == 0) stats1.errortime_hh = $time;
			stats1.errors_hh = stats1.errors_hh+1'b1; end
		if (mm_ref !== ( mm_ref ^ mm_dut ^ mm_ref ))
		begin if (stats1.errors_mm == 0) stats1.errortime_mm = $time;
			stats1.errors_mm = stats1.errors_mm+1'b1; end
		if (ss_ref !== ( ss_ref ^ ss_dut ^ ss_ref ))
		begin if (stats1.errors_ss == 0) stats1.errortime_ss = $time;
			stats1.errors_ss = stats1.errors_ss+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input reset,
	input ena,
	output reg pm,
	output reg [7:0] hh,
	output reg [7:0] mm,
	output reg [7:0] ss);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input reset,
	input ena,
	output reg pm,
	output reg [7:0] hh,
	output reg [7:0] mm,
	output reg [7:0] ss);

	wire [6:0] enable = {
		{hh[7:0],mm[7:0],ss[7:0]}==24'h115959,
		{hh[3:0],mm[7:0],ss[7:0]}==20'h95959,
		{mm[7:0],ss[7:0]}==16'h5959,
		{mm[3:0],ss[7:0]}==12'h959,
		ss[7:0]==8'h59,
		ss[3:0] == 4'h9,
		1'b1};

	always @(posedge clk)
		if (reset)
			{pm,hh,mm,ss} <= 25'h0120000;
		else if (ena) begin
			if (enable[0] && ss[3:0] == 9) ss[3:0] <= 0;
			else if (enable[0]) ss[3:0] <= ss[3:0] + 1;

			if (enable[1] && ss[7:4] == 4'h5) ss[7:4] <= 0;
			else if (enable[1]) ss[7:4] <= ss[7:4] + 1;

			if (enable[2] && mm[3:0] == 9) mm[3:0] <= 0;
			else if (enable[2]) mm[3:0] <= mm[3:0] + 1;

			if (enable[3] && mm[7:4] == 4'h5) mm[7:4] <= 0;
			else if (enable[3]) mm[7:4] <= mm[7:4] + 1;

			if (enable[4] && hh[3:0] == 4'h9) hh[3:0] <= 0;
			else if (enable[4]) hh[3:0] <= hh[3:0] + 1;

			if (enable[4] && hh[7:0] == 8'h12) hh[7:0] <= 8'h1;
			else if (enable[5]) hh[7:4] <= hh[7:4] + 1;

			if (enable[6]) pm <= ~pm;
		end
endmodule

module stimulus_gen (
	input clk,
	output reg reset,
	output reg ena,
	input [7:0] hh_dut, mm_dut, ss_dut,
	input pm_dut,
	input tb_match,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable
);
	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	logic bcd_fail = 0;
	logic reset_fail = 0;

	always @(posedge clk) begin
		if ((hh_dut[3:0] >= 4'ha) ||
			(hh_dut[7:4] >= 4'ha) ||
			(mm_dut[3:0] >= 4'ha) ||
			(mm_dut[7:4] >= 4'ha) ||
			(ss_dut[3:0] >= 4'ha) ||
			(ss_dut[7:4] >= 4'ha))
			bcd_fail <= 1'b1;
	end

	initial begin
		reset <= 1;
		ena <= 1;
		wavedrom_start("Reset and count to 10");
		reset_test();
		repeat(12) @(posedge clk);
		wavedrom_stop();
		ena <= 1'b1;
		reset <= 1'b1;
		@(posedge clk);
		@(posedge clk)
			if (!tb_match) begin
				$display("Hint: Clock seems to reset to %02x:%02x:%02x %s (Should be 12:00:00 AM).", hh_dut, mm_dut, ss_dut, pm_dut ? "PM": "AM");
				reset_fail <= 1'b1;
			end

		reset <= 1'b0;
		@(posedge clk);
		@(posedge clk);
		@(posedge clk);
		ena <= 1'b0;
		reset <= 1'b1;
		@(posedge clk);
		@(posedge clk)
			if (!tb_match && !reset_fail)
				$display("Hint: Reset has higher priority than enable and should occur even if not enabled.");

		repeat(400) @(posedge clk, negedge clk) begin
			reset <= !($random & 31);
			ena <= !($random & 3);
		end
		reset <= 1;
		@(posedge clk) begin
			{reset, ena} <= 2'b1;
		end

		repeat(55) @(posedge clk);
		wavedrom_start("Minute roll-over");
		repeat(10) @(posedge clk);
		wavedrom_stop();

		repeat(3530) @(posedge clk);
		wavedrom_start("Hour roll-over");
		repeat(10) @(posedge clk);
		wavedrom_stop();

		repeat(39590) @(posedge clk);
		wavedrom_start("PM roll-over");
		repeat(10) @(posedge clk);
		wavedrom_stop();

		repeat(132745) @(posedge clk);
		repeat(50) @(posedge clk, negedge clk) begin
			ena <= !($random & 7);
		end
		reset <= 1'b1;
		repeat(5) @(posedge clk);

		if (bcd_fail)
			$display("Hint: Non-BCD values detected. Are you sure you're using two-digit BCD representation for hh, mm, and ss?");

		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_pm;
		int errortime_pm;
		int errors_hh;
		int errortime_hh;
		int errors_mm;
		int errortime_mm;
		int errors_ss;
		int errortime_ss;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic reset;
	logic ena;
	logic pm_ref;
	logic pm_dut;
	logic [7:0] hh_ref;
	logic [7:0] hh_dut;
	logic [7:0] mm_ref;
	logic [7:0] mm_dut;
	logic [7:0] ss_ref;
	logic [7:0] ss_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,reset,ena,pm_ref,pm_dut,hh_ref,hh_dut,mm_ref,mm_dut,ss_ref,ss_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.reset,
		.ena );
	reference_module good1 (
		.clk,
		.reset,
		.ena,
		.pm(pm_ref),
		.hh(hh_ref),
		.mm(mm_ref),
		.ss(ss_ref) );

	top_module top_module1 (
		.clk,
		.reset,
		.ena,
		.pm(pm_dut),
		.hh(hh_dut),
		.mm(mm_dut),
		.ss(ss_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_pm) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "pm", stats1.errors_pm, stats1.errortime_pm);
		else $display("Hint: Output '%s' has no mismatches.", "pm");
		if (stats1.errors_hh) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "hh", stats1.errors_hh, stats1.errortime_hh);
		else $display("Hint: Output '%s' has no mismatches.", "hh");
		if (stats1.errors_mm) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "mm", stats1.errors_mm, stats1.errortime_mm);
		else $display("Hint: Output '%s' has no mismatches.", "mm");
		if (stats1.errors_ss) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "ss", stats1.errors_ss, stats1.errortime_ss);
		else $display("Hint: Output '%s' has no mismatches.", "ss");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { pm_ref, hh_ref, mm_ref, ss_ref } === ( { pm_ref, hh_ref, mm_ref, ss_ref } ^ { pm_dut, hh_dut, mm_dut, ss_dut } ^ { pm_ref, hh_ref, mm_ref, ss_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (pm_ref !== ( pm_ref ^ pm_dut ^ pm_ref ))
		begin if (stats1.errors_pm == 0) stats1.errortime_pm = $time;
			stats1.errors_pm = stats1.errors_pm+1'b1; end
		if (hh_ref !== ( hh_ref ^ hh_dut ^ hh_ref ))
		begin if (stats1.errors_hh == 0) stats1.errortime_hh = $time;
			stats1.errors_hh = stats1.errors_hh+1'b1; end
		if (mm_ref !== ( mm_ref ^ mm_dut ^ mm_ref ))
		begin if (stats1.errors_mm == 0) stats1.errortime_mm = $time;
			stats1.errors_mm = stats1.errors_mm+1'b1; end
		if (ss_ref !== ( ss_ref ^ ss_dut ^ ss_ref ))
		begin if (stats1.errors_ss == 0) stats1.errortime_ss = $time;
			stats1.errors_ss = stats1.errors_ss+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input reset,
	output [3:1] ena,
	output reg [15:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input reset,
	output [3:1] ena,
	output reg [15:0] q);

	wire [3:0] enable = { q[11:0]==12'h999, q[7:0]==8'h99, q[3:0] == 4'h9, 1'b1};
	assign ena = enable[3:1];
	always @(posedge clk)
		for (int i=0;i<4;i++) begin
			if (reset || (q[i*4 +:4] == 9 && enable[i]))
				q[i*4 +:4] <= 0;
			else if (enable[i])
				q[i*4 +:4] <= q[i*4 +:4]+1;
		end

endmodule

module stimulus_gen (
	input clk,
	output reg reset,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	input tb_match
);

	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		reset <= 1;
		reset_test();
		repeat(2) @(posedge clk);
		@(negedge clk);
		wavedrom_start("Counting");
			repeat(12) @(posedge clk);
		@(negedge clk);
		wavedrom_stop();
		repeat(71) @(posedge clk);
		@(negedge clk) wavedrom_start("100 rollover");
			repeat(16) @(posedge clk);
		@(negedge clk) wavedrom_stop();
		repeat(400) @(posedge clk, negedge clk)
			reset <= !($random & 31);
		repeat(19590) @(posedge clk);
		reset <= 1'b1;
		repeat(5) @(posedge clk);
		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_ena;
		int errortime_ena;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic reset;
	logic [3:1] ena_ref;
	logic [3:1] ena_dut;
	logic [15:0] q_ref;
	logic [15:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,reset,ena_ref,ena_dut,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.reset );
	reference_module good1 (
		.clk,
		.reset,
		.ena(ena_ref),
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.reset,
		.ena(ena_dut),
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_ena) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "ena", stats1.errors_ena, stats1.errortime_ena);
		else $display("Hint: Output '%s' has no mismatches.", "ena");
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { ena_ref, q_ref } === ( { ena_ref, q_ref } ^ { ena_dut, q_dut } ^ { ena_ref, q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (ena_ref !== ( ena_ref ^ ena_dut ^ ena_ref ))
		begin if (stats1.errors_ena == 0) stats1.errortime_ena = $time;
			stats1.errors_ena = stats1.errors_ena+1'b1; end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input reset,
	output [3:1] ena,
	output reg [15:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input reset,
	output [3:1] ena,
	output reg [15:0] q);

	wire [3:0] enable = { q[11:0]==12'h999, q[7:0]==8'h99, q[3:0] == 4'h9, 1'b1};
	assign ena = enable[3:1];
	always @(posedge clk)
		for (int i=0;i<4;i++) begin
			if (reset || (q[i*4 +:4] == 9 && enable[i]))
				q[i*4 +:4] <= 0;
			else if (enable[i])
				q[i*4 +:4] <= q[i*4 +:4]+1;
		end

endmodule

module stimulus_gen (
	input clk,
	output reg reset,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	input tb_match
);

	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	initial begin
		reset <= 1;
		reset_test();
		repeat(2) @(posedge clk);
		@(negedge clk);
		wavedrom_start("Counting");
			repeat(12) @(posedge clk);
		@(negedge clk);
		wavedrom_stop();
		repeat(71) @(posedge clk);
		@(negedge clk) wavedrom_start("100 rollover");
			repeat(16) @(posedge clk);
		@(negedge clk) wavedrom_stop();
		repeat(400) @(posedge clk, negedge clk)
			reset <= !($random & 31);
		repeat(19590) @(posedge clk);
		reset <= 1'b1;
		repeat(5) @(posedge clk);
		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_ena;
		int errortime_ena;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic reset;
	logic [3:1] ena_ref;
	logic [3:1] ena_dut;
	logic [15:0] q_ref;
	logic [15:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,reset,ena_ref,ena_dut,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.reset );
	reference_module good1 (
		.clk,
		.reset,
		.ena(ena_ref),
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.reset,
		.ena(ena_dut),
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_ena) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "ena", stats1.errors_ena, stats1.errortime_ena);
		else $display("Hint: Output '%s' has no mismatches.", "ena");
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { ena_ref, q_ref } === ( { ena_ref, q_ref } ^ { ena_dut, q_dut } ^ { ena_ref, q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (ena_ref !== ( ena_ref ^ ena_dut ^ ena_ref ))
		begin if (stats1.errors_ena == 0) stats1.errortime_ena = $time;
			stats1.errors_ena = stats1.errors_ena+1'b1; end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule


Prompt:
module top_module(
    input clk,
    input areset,
    input train_valid,
    input train_taken,
    output logic [1:0] state
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
    input clk,
    input areset,
    input train_valid,
    input train_taken,
    output logic [1:0] state
);
    always @(posedge clk, posedge areset) begin
        if (areset)
            state <= 1;
        else if (train_valid) begin
            if(state < 3 && train_taken)
                state <= state + 1;
            else if(state > 0 && !train_taken)
                state <= state - 1;
        end
    end
endmodule

module stimulus_gen(
	input clk,
	output logic areset,
	output logic train_valid,
	output train_taken,

	input tb_match,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	output int wavedrom_hide_after_time
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	reg reset;
	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

	assign areset = reset;
	logic train_taken_r;
	assign train_taken = train_valid ? train_taken_r : 1'bx;

	initial begin
		@(posedge clk);
		@(posedge clk) reset <= 1;
		@(posedge clk) reset <= 0;
		train_taken_r <= 1;
		train_valid <= 1;

		wavedrom_start("Asynchronous reset");
			reset_test(1); // Test for asynchronous reset
		wavedrom_stop();
		@(posedge clk) reset <= 1;
		train_taken_r <= 1;
		train_valid <= 0;
		@(posedge clk) reset <= 0;

		wavedrom_start("Count up, then down");
		train_taken_r <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
		train_taken_r <= 0;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
		wavedrom_stop();

		repeat(1000) @(posedge clk,negedge clk)
			{train_valid, train_taken_r} <= {$urandom} ;

		#1 $finish;
	end

endmodule
module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_state;
		int errortime_state;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic areset;
	logic train_valid;
	logic train_taken;
	logic [1:0] state_ref;
	logic [1:0] state_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,areset,train_valid,train_taken,state_ref,state_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.areset,
		.train_valid,
		.train_taken );
	reference_module good1 (
		.clk,
		.areset,
		.train_valid,
		.train_taken,
		.state(state_ref) );

	top_module top_module1 (
		.clk,
		.areset,
		.train_valid,
		.train_taken,
		.state(state_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_state) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "state", stats1.errors_state, stats1.errortime_state);
		else $display("Hint: Output '%s' has no mismatches.", "state");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { state_ref } === ( { state_ref } ^ { state_dut } ^ { state_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (state_ref !== ( state_ref ^ state_dut ^ state_ref ))
		begin if (stats1.errors_state == 0) stats1.errortime_state = $time;
			stats1.errors_state = stats1.errors_state+1'b1; end

	end
endmodule


Prompt:
module top_module(
    input clk,
    input areset,
    input train_valid,
    input train_taken,
    output logic [1:0] state
);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
    input clk,
    input areset,
    input train_valid,
    input train_taken,
    output logic [1:0] state
);
    always @(posedge clk, posedge areset) begin
        if (areset)
            state <= 1;
        else if (train_valid) begin
            if(state < 3 && train_taken)
                state <= state + 1;
            else if(state > 0 && !train_taken)
                state <= state - 1;
        end
    end
endmodule

module stimulus_gen(
	input clk,
	output logic areset,
	output logic train_valid,
	output train_taken,

	input tb_match,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	output int wavedrom_hide_after_time
);

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	reg reset;
	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

	assign areset = reset;
	logic train_taken_r;
	assign train_taken = train_valid ? train_taken_r : 1'bx;

	initial begin
		@(posedge clk);
		@(posedge clk) reset <= 1;
		@(posedge clk) reset <= 0;
		train_taken_r <= 1;
		train_valid <= 1;

		wavedrom_start("Asynchronous reset");
			reset_test(1); // Test for asynchronous reset
		wavedrom_stop();
		@(posedge clk) reset <= 1;
		train_taken_r <= 1;
		train_valid <= 0;
		@(posedge clk) reset <= 0;

		wavedrom_start("Count up, then down");
		train_taken_r <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
		train_taken_r <= 0;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 1;
			@(posedge clk) train_valid <= 0;
			@(posedge clk) train_valid <= 1;
		wavedrom_stop();

		repeat(1000) @(posedge clk,negedge clk)
			{train_valid, train_taken_r} <= {$urandom} ;

		#1 $finish;
	end

endmodule
module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_state;
		int errortime_state;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic areset;
	logic train_valid;
	logic train_taken;
	logic [1:0] state_ref;
	logic [1:0] state_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,areset,train_valid,train_taken,state_ref,state_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.areset,
		.train_valid,
		.train_taken );
	reference_module good1 (
		.clk,
		.areset,
		.train_valid,
		.train_taken,
		.state(state_ref) );

	top_module top_module1 (
		.clk,
		.areset,
		.train_valid,
		.train_taken,
		.state(state_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_state) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "state", stats1.errors_state, stats1.errortime_state);
		else $display("Hint: Output '%s' has no mismatches.", "state");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { state_ref } === ( { state_ref } ^ { state_dut } ^ { state_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (state_ref !== ( state_ref ^ state_dut ^ state_ref ))
		begin if (stats1.errors_state == 0) stats1.errortime_state = $time;
			stats1.errors_state = stats1.errors_state+1'b1; end

	end
endmodule


Prompt:
module top_module(
	input clk,
	input slowena,
	input reset,
	output reg [3:0] q);

`timescale 1 ps/1 ps
`define OK 12
`define INCORRECT 13
module reference_module(
	input clk,
	input slowena,
	input reset,
	output reg [3:0] q);

	always @(posedge clk)
		if (reset)
			q <= 0;
		else if (slowena) begin
			if (q == 9)
				q <= 0;
			else
				q <= q+1;
		end

endmodule

module stimulus_gen (
	input clk,
	output reg slowena,
	output reg reset,
	output reg[511:0] wavedrom_title,
	output reg wavedrom_enable,
	input tb_match
);

	task reset_test(input async=0);
		bit arfail, srfail, datafail;

		@(posedge clk);
		@(posedge clk) reset <= 0;
		repeat(3) @(posedge clk);

		@(negedge clk) begin datafail = !tb_match ; reset <= 1; end
		@(posedge clk) arfail = !tb_match;
		@(posedge clk) begin
			srfail = !tb_match;
			reset <= 0;
		end
		if (srfail)
			$display("Hint: Your reset doesn't seem to be working.");
		else if (arfail && (async || !datafail))
			$display("Hint: Your reset should be %0s, but doesn't appear to be.", async ? "asynchronous" : "synchronous");
		// Don't warn about synchronous reset if the half-cycle before is already wrong. It's more likely
		// a functionality error than the reset being implemented asynchronously.

	endtask

// Add two ports to module stimulus_gen:
//    output [511:0] wavedrom_title
//    output reg wavedrom_enable

	task wavedrom_start(input[511:0] title = "");
	endtask

	task wavedrom_stop;
		#1;
	endtask

	reg hint1;
	initial begin
		reset <= 1;
		slowena <= 1;
		wavedrom_start("Synchronous reset and counting.");
		reset_test();
		repeat(12) @(posedge clk);
		wavedrom_stop();
		@(posedge clk);

		//wavedrom_start("Testing.");
		reset <= 1;
		@(posedge clk);
		reset <= 0;
		repeat(9) @(posedge clk);
		slowena <= 0;
		@(negedge clk) hint1 = tb_match;
		repeat(3) @(posedge clk);
		if (hint1 && !tb_match) begin
			$display ("Hint: What is supposed to happen when the counter is 9 and not enabled?");
		end
		//wavedrom_stop();
		slowena <= 1;
		reset <= 1;
		@(posedge clk);
		reset <= 0;

		wavedrom_start("Enable/disable");
		repeat(15) @(posedge clk) slowena <= !($random & 1);
		wavedrom_stop();
		@(posedge clk);

		repeat(400) @(posedge clk, negedge clk) begin
			slowena <= !($random&3);
			reset <= !($random & 31);
		end
		#1 $finish;
	end

endmodule

module tb();

	typedef struct packed {
		int errors;
		int errortime;
		int errors_q;
		int errortime_q;

		int clocks;
	} stats;

	stats stats1;

	wire[511:0] wavedrom_title;
	wire wavedrom_enable;
	int wavedrom_hide_after_time;

	reg clk=0;
	initial forever
		#5 clk = ~clk;

	logic slowena;
	logic reset;
	logic [3:0] q_ref;
	logic [3:0] q_dut;

	initial begin
		$dumpfile("wave.vcd");
		$dumpvars(1, stim1.clk, tb_mismatch ,clk,slowena,reset,q_ref,q_dut );
	end

	wire tb_match;		// Verification
	wire tb_mismatch = ~tb_match;

	stimulus_gen stim1 (
		.clk,
		.* ,
		.slowena,
		.reset );
	reference_module good1 (
		.clk,
		.slowena,
		.reset,
		.q(q_ref) );

	top_module top_module1 (
		.clk,
		.slowena,
		.reset,
		.q(q_dut) );

	bit strobe = 0;
	task wait_for_end_of_timestep;
		repeat(5) begin
			strobe <= !strobe;  // Try to delay until the very end of the time step.
			@(strobe);
		end
	endtask

	final begin
		if (stats1.errors_q) $display("Hint: Output '%s' has %0d mismatches. First mismatch occurred at time %0d.", "q", stats1.errors_q, stats1.errortime_q);
		else $display("Hint: Output '%s' has no mismatches.", "q");

		$display("Hint: Total mismatched samples is %1d out of %1d samples\n", stats1.errors, stats1.clocks);
		$display("Simulation finished at %0d ps", $time);
		$display("Mismatches: %1d in %1d samples", stats1.errors, stats1.clocks);
	end

	// Verification: XORs on the right makes any X in good_vector match anything, but X in dut_vector will only match X.
	assign tb_match = ( { q_ref } === ( { q_ref } ^ { q_dut } ^ { q_ref } ) );
	// Use explicit sensitivity list here. @(*) causes NetProc::nex_input() to be called when trying to compute
	// the sensitivity list of the @(strobe) process, which isn't implemented.
	always @(posedge clk, negedge clk) begin

		stats1.clocks++;
		if (!tb_match) begin
			if (stats1.errors == 0) stats1.errortime = $time;
			stats1.errors++;
		end
		if (q_ref !== ( q_ref ^ q_dut ^ q_ref ))
		begin if (stats1.errors_q == 0) stats1.errortime_q = $time;
			stats1.errors_q = stats1.errors_q+1'b1; end

	end
endmodule