From 456810b09e60eb57089e02fd3603754056c97d23 Mon Sep 17 00:00:00 2001
From: Luke Wren <wren6991@gmail.com>
Date: Tue, 24 May 2022 22:56:13 +0100
Subject: [PATCH] Make vcd generation optional in runtests

---
 test/sim/sw_testcases/runtests    | 16 +++++++++++++---
 test/sim/sw_testcases/umode_wfi.c |  2 +-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/test/sim/sw_testcases/runtests b/test/sim/sw_testcases/runtests
index 723303a..1f2b852 100755
--- a/test/sim/sw_testcases/runtests
+++ b/test/sim/sw_testcases/runtests
@@ -4,9 +4,15 @@ import os
 import subprocess
 import sys
 
+args = sys.argv[1:]
 
-if len(sys.argv) > 1:
-	testlist = sys.argv[1:]
+generate_vcd = False
+if "--vcd" in args:
+	generate_vcd = True
+	del args[args.index("--vcd")]
+
+if len(args) > 0:
+	testlist = args
 else:
 	testlist = []
 	for path in os.listdir():
@@ -36,8 +42,12 @@ for test in testlist:
 		all_passed = False
 		continue
 
+	cmdline = ["../tb_cxxrtl/tb", "--bin", f"tmp/{test}.bin", "--cycles", "1000000"]
+	if generate_vcd:
+		cmdline += ["--vcd", f"tmp/{test}.vcd"]
+
 	test_run_ret = subprocess.run(
-		["../tb_cxxrtl/tb", "--bin", f"tmp/{test}.bin", "--cycles", "1000000", "--vcd", f"tmp/{test}.vcd"],
+		cmdline,
 		stdout = subprocess.PIPE,
 		stderr = subprocess.PIPE,
 		timeout=10
diff --git a/test/sim/sw_testcases/umode_wfi.c b/test/sim/sw_testcases/umode_wfi.c
index 683696b..8f7c4d3 100644
--- a/test/sim/sw_testcases/umode_wfi.c
+++ b/test/sim/sw_testcases/umode_wfi.c
@@ -29,7 +29,7 @@ void __attribute__((naked)) do_ecall() {
 // /!\ Unconventional control flow ahead
 
 // Call function in U mode, from M mode. Catch exception, or break back to M
-// mode if the function returned normally, and then return.
+// mode if the function returned normally (via dummy ecall), and then return.
 static inline void umode_call_and_catch(void (*f)(void)) {
 	clear_csr(mstatus, 0x1800u);
 	write_csr(mepc, f);