From 549787227a488a4f52e30ee0b14cb9bf331b327c Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Mon, 10 Aug 2020 15:57:38 -0700
Subject: [PATCH] Core: Add mTimingScheduleAbsolute

---
 include/mgba/core/timing.h | 1 +
 src/core/timing.c          | 4 ++++
 src/gba/timer.c            | 3 +--
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/mgba/core/timing.h b/include/mgba/core/timing.h
index 10a64171e..3db79493c 100644
--- a/include/mgba/core/timing.h
+++ b/include/mgba/core/timing.h
@@ -35,6 +35,7 @@ void mTimingInit(struct mTiming* timing, int32_t* relativeCycles, int32_t* nextE
 void mTimingDeinit(struct mTiming* timing);
 void mTimingClear(struct mTiming* timing);
 void mTimingSchedule(struct mTiming* timing, struct mTimingEvent*, int32_t when);
+void mTimingScheduleAbsolute(struct mTiming* timing, struct mTimingEvent*, int32_t when);
 void mTimingDeschedule(struct mTiming* timing, struct mTimingEvent*);
 bool mTimingIsScheduled(const struct mTiming* timing, const struct mTimingEvent*);
 int32_t mTimingTick(struct mTiming* timing, int32_t cycles);
diff --git a/src/core/timing.c b/src/core/timing.c
index f9854c6ac..ddee6d332 100644
--- a/src/core/timing.c
+++ b/src/core/timing.c
@@ -50,6 +50,10 @@ void mTimingSchedule(struct mTiming* timing, struct mTimingEvent* event, int32_t
 	*previous = event;
 }
 
+void mTimingScheduleAbsolute(struct mTiming* timing, struct mTimingEvent* event, int32_t when) {
+	mTimingSchedule(timing, event, when - mTimingCurrentTime(timing));
+}
+
 void mTimingDeschedule(struct mTiming* timing, struct mTimingEvent* event) {
 	if (timing->reroot) {
 		timing->root = timing->reroot;
diff --git a/src/gba/timer.c b/src/gba/timer.c
index 512a1d05f..5b1bc5414 100644
--- a/src/gba/timer.c
+++ b/src/gba/timer.c
@@ -109,9 +109,8 @@ void GBATimerUpdateRegister(struct GBA* gba, int timer, int32_t cyclesLate) {
 	tickIncrement = (0x10000 - tickIncrement) << prescaleBits;
 	currentTime += tickIncrement;
 	currentTime &= ~tickMask;
-	currentTime -= mTimingCurrentTime(&gba->timing);
 	mTimingDeschedule(&gba->timing, &currentTimer->event);
-	mTimingSchedule(&gba->timing, &currentTimer->event, currentTime);
+	mTimingScheduleAbsolute(&gba->timing, &currentTimer->event, currentTime);
 }
 
 void GBATimerWriteTMCNT_LO(struct GBA* gba, int timer, uint16_t reload) {