From 54ee00b0f6997e1c76b02ca6be2b593690d889ac Mon Sep 17 00:00:00 2001
From: Koen De Vleeschauwer <kdv@kdvelectronics.eu>
Date: Wed, 13 May 2020 13:54:18 +0200
Subject: [PATCH] set semihosting sys_clock time origin

---
 src/target/cortexm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/target/cortexm.c b/src/target/cortexm.c
index c95b52ab..4e47a23b 100644
--- a/src/target/cortexm.c
+++ b/src/target/cortexm.c
@@ -71,6 +71,10 @@ static target_addr cortexm_check_watch(target *t);
 
 static int cortexm_hostio_request(target *t);
 
+#if !defined(PC_HOSTED)
+static uint32_t time0_sec = UINT32_MAX; /* sys_clock time origin */
+#endif
+
 struct cortexm_priv {
 	ADIv5_AP_t *ap;
 	bool stepping;
@@ -1206,6 +1210,8 @@ static int cortexm_hostio_request(target *t)
 		if (syscall == SYS_TIME) { /* SYS_TIME: time in seconds */
 			ret = sec;
 		} else { /* SYS_CLOCK: time in hundredths of seconds */
+			if (time0_sec > sec) time0_sec = sec; /* set sys_clock time origin */
+			sec -= time0_sec;
 			uint64_t csec64 = (sec * 1000000ull + usec)/10000ull;
 			uint32_t csec = csec64 & 0x7fffffff;
 			ret = csec;