From 9a5d35c19559a65826ea42d575d8085a682b94f6 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Sun, 10 Apr 2016 12:35:16 +0200
Subject: [PATCH] Using Verilator in torture test bench

---
 scripts/torture/.gitignore   |  1 +
 scripts/torture/Makefile     | 16 +++++++++++++---
 scripts/torture/testbench.cc | 18 ++++++++++++++++++
 scripts/torture/testbench.v  | 25 ++++++++++++++-----------
 4 files changed, 46 insertions(+), 14 deletions(-)
 create mode 100644 scripts/torture/testbench.cc

diff --git a/scripts/torture/.gitignore b/scripts/torture/.gitignore
index a1de2e4..a9db520 100644
--- a/scripts/torture/.gitignore
+++ b/scripts/torture/.gitignore
@@ -2,6 +2,7 @@
 riscv-fesvr
 riscv-isa-sim
 riscv-torture
+obj_dir
 tests
 test.S
 test.elf
diff --git a/scripts/torture/Makefile b/scripts/torture/Makefile
index e9bea89..38051f0 100644
--- a/scripts/torture/Makefile
+++ b/scripts/torture/Makefile
@@ -1,4 +1,10 @@
 
+# Icarus Verilog
+#TESTBENCH_EXE = tests/testbench.vvp
+
+# Verilator
+TESTBENCH_EXE = obj_dir/Vtestbench
+
 test: riscv-torture/build.ok riscv-isa-sim/build.ok
 	bash test.sh
 
@@ -28,6 +34,10 @@ batch_list = $(shell bash -c 'for i in {0..999}; do printf "%03d\n" $$i; done')
 
 batch: $(addprefix tests/test_,$(addsuffix .ok,$(batch_list)))
 
+obj_dir/Vtestbench: testbench.v testbench.cc ../../picorv32.v
+	verilator --exe -Wno-fatal --cc --top-module testbench testbench.v ../../picorv32.v testbench.cc
+	$(MAKE) -C obj_dir -f Vtestbench.mk
+
 tests/testbench.vvp: testbench.v ../../picorv32.v
 	mkdir -p tests
 	iverilog -o tests/testbench.vvp testbench.v ../../picorv32.v
@@ -55,8 +65,8 @@ tests/test_$(1).hex: tests/test_$(1).bin
 tests/test_$(1).ref: tests/test_$(1).elf riscv-isa-sim/build.ok
 	LD_LIBRARY_PATH="./riscv-isa-sim:./riscv-fesvr" ./riscv-isa-sim/spike tests/test_$(1).elf > tests/test_$(1).ref
 
-tests/test_$(1).ok: tests/testbench.vvp tests/test_$(1).hex tests/test_$(1).ref
-	vvp tests/testbench.vvp +hex=tests/test_$(1).hex +ref=tests/test_$(1).ref | tee tests/test_$(1).out
+tests/test_$(1).ok: $(TESTBENCH_EXE) tests/test_$(1).hex tests/test_$(1).ref
+	$(TESTBENCH_EXE) +hex=tests/test_$(1).hex +ref=tests/test_$(1).ref | tee tests/test_$(1).out
 	grep -q PASSED tests/test_$(1).out
 	mv tests/test_$(1).out tests/test_$(1).ok
 endef
@@ -71,7 +81,7 @@ loop:
 	done
 
 clean:
-	rm -rf riscv-torture riscv-fesvr riscv-isa-sim tests
+	rm -rf riscv-torture riscv-fesvr riscv-isa-sim tests obj_dir
 	rm -f test.S test.elf test.bin test.hex test.ref test.vvp
 
 .PHONY: test batch loop clean
diff --git a/scripts/torture/testbench.cc b/scripts/torture/testbench.cc
new file mode 100644
index 0000000..2925d0b
--- /dev/null
+++ b/scripts/torture/testbench.cc
@@ -0,0 +1,18 @@
+#include "Vtestbench.h"
+#include "verilated.h"
+
+int main(int argc, char **argv, char **env)
+{
+	Verilated::commandArgs(argc, argv);
+	Vtestbench* top = new Vtestbench;
+
+	top->clk = 0;
+	while (!Verilated::gotFinish()) {
+		top->clk = !top->clk;
+		top->eval();
+	}
+
+	delete top;
+	exit(0);
+}
+
diff --git a/scripts/torture/testbench.v b/scripts/torture/testbench.v
index 41f3495..088b7aa 100644
--- a/scripts/torture/testbench.v
+++ b/scripts/torture/testbench.v
@@ -33,25 +33,20 @@ module testbench (
 		.mem_rdata   (mem_rdata   )
 	);
 
-	reg [1023:0] hex_filename;
-	reg [1023:0] ref_filename;
+	localparam integer filename_len = 18;
+	reg [8*filename_len-1:0] hex_filename;
+	reg [8*filename_len-1:0] ref_filename;
 
 	reg [31:0] memory [0:4095];
 	reg [31:0] memory_ref [0:4095];
 	integer i, errcount;
+	integer cycle = 0;
 
 	initial begin
 		if ($value$plusargs("hex=%s", hex_filename)) $readmemh(hex_filename, memory);
 		if ($value$plusargs("ref=%s", ref_filename)) $readmemh(ref_filename, memory_ref);
 		// $dumpfile("testbench.vcd");
 		// $dumpvars(0, testbench);
-
-		repeat (10) @(posedge clk);
-		resetn <= 1;
-
-		repeat (100000) @(posedge clk);
-		$display("FAILED: Timeout!");
-		$finish;
 	end
 
 	always @(posedge clk) begin
@@ -79,10 +74,18 @@ module testbench (
 				end
 			end
 			if (errcount)
-				$display("FAILED: Got %1d errors for %1s => %1s!", errcount, hex_filename, ref_filename);
+				$display("FAILED: Got %1d errors for %s => %s!", errcount, hex_filename, ref_filename);
 			else
-				$display("PASSED %1s => %1s.", hex_filename, ref_filename);
+				$display("PASSED %s => %s.", hex_filename, ref_filename);
 			$finish;
 		end
+
+		if (cycle > 100000) begin
+			$display("FAILED: Timeout!");
+			$finish;
+		end
+
+		resetn <= cycle > 10;
+		cycle <= cycle + 1;
 	end
 endmodule