From e4df12dbe2ffdec4b43911ef895372f8cf97972c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Stensg=C3=A5rd?= <mastensg@mastensg.net>
Date: Sun, 27 Apr 2025 19:32:13 +0200
Subject: verilator_example_tracing: dump value change

---
 verilator_example_tracing/.gitignore  |  1 +
 verilator_example_tracing/Makefile    | 13 +++++++++++++
 verilator_example_tracing/hello.v     | 15 +++++++++++++++
 verilator_example_tracing/sim_main.cc | 25 +++++++++++++++++++++++++
 4 files changed, 54 insertions(+)
 create mode 100644 verilator_example_tracing/.gitignore
 create mode 100644 verilator_example_tracing/Makefile
 create mode 100644 verilator_example_tracing/hello.v
 create mode 100644 verilator_example_tracing/sim_main.cc

diff --git a/verilator_example_tracing/.gitignore b/verilator_example_tracing/.gitignore
new file mode 100644
index 0000000..d38e9f1
--- /dev/null
+++ b/verilator_example_tracing/.gitignore
@@ -0,0 +1 @@
+/obj_dir
diff --git a/verilator_example_tracing/Makefile b/verilator_example_tracing/Makefile
new file mode 100644
index 0000000..fc2f775
--- /dev/null
+++ b/verilator_example_tracing/Makefile
@@ -0,0 +1,13 @@
+all: obj_dir/Vhello
+
+check: all
+	obj_dir/Vhello
+
+clean:
+	rm -fr obj_dir
+
+.PHONY: all check clean
+
+obj_dir/Vhello: hello.v sim_main.cc
+	verilator --cc --exe --trace --build -j 0 -Wall hello.v sim_main.cc
+	#verilator --cc --exe --trace --build -j 0 -Wall -O3 --x-assign fast --x-initial fast --noassert hello.v sim_main.cc
diff --git a/verilator_example_tracing/hello.v b/verilator_example_tracing/hello.v
new file mode 100644
index 0000000..a62addb
--- /dev/null
+++ b/verilator_example_tracing/hello.v
@@ -0,0 +1,15 @@
+module hello(input clk);
+	reg [31:0]	i = 0;
+	initial begin
+		$display("start");
+		$dumpfile("dump.vcd");
+		$dumpvars();
+	end
+	always @(posedge clk) begin
+		if (i == 1000) begin
+			$display("stop");
+			$finish;
+		end
+		i <= i+1;
+	end
+endmodule
diff --git a/verilator_example_tracing/sim_main.cc b/verilator_example_tracing/sim_main.cc
new file mode 100644
index 0000000..bcb5fa7
--- /dev/null
+++ b/verilator_example_tracing/sim_main.cc
@@ -0,0 +1,25 @@
+#include <cstdio>
+
+#include "Vhello.h"
+#include "verilated.h"
+
+int
+main(int argc, char **argv)
+{
+	VerilatedContext *cp = new VerilatedContext;
+	cp->traceEverOn(true);
+	cp->commandArgs(argc, argv);
+
+	Vhello *top = new Vhello{cp};
+	top->clk = 0;
+
+	while (!cp->gotFinish()) {
+		cp->timeInc(1);
+
+		top->clk = !top->clk;
+		top->eval();
+	}
+	top->final();
+	VL_PRINTF("[%" PRId64 "]\n", cp->time());
+	fprintf(stderr, "it finished.\n");
+}
-- 
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