Core: Add mTimingScheduleAbsolute

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);

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;

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) {