all repos — mgba @ fa92b4cd0e461ede2a70077c8acf87078a931d05

mGBA Game Boy Advance Emulator

GBA: Count up timers should not count themselves
Jeffrey Pfau jeffrey@endrift.com
Wed, 14 Sep 2016 01:34:53 -0700
commit

fa92b4cd0e461ede2a70077c8acf87078a931d05

parent

dd76386f4cee134237f6a86c37f178eeca8bd44b

3 files changed, 16 insertions(+), 9 deletions(-)

jump to
M CHANGES → CHANGES 
@@ -40,6 +40,7 @@ - GBA: Timer 0 cannot be count up
  - Qt: Fix being unable to pause manually when using auto-pausing
  - GBA Memory: Fix ldm {pc}
  - GBA Video: Fix out-of-order OBJWIN
+ - GBA: Count up timers should not count themselves
 Misc:
  - 3DS: Use blip_add_delta_fast for a small speed improvement
  - OpenGL: Log shader compilation failure
M src/gba/gba.c → src/gba/gba.c 
@@ -306,7 +306,7 @@ struct GBATimer* timer;
 		struct GBATimer* nextTimer;
 
 		timer = &gba->timers[0];
-		if (GBATimerFlagsIsEnable(timer->flags)) {
+		if (GBATimerFlagsIsEnable(timer->flags) && timer->nextEvent != INT_MAX) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			while (timer->nextEvent <= 0) {

@@ -333,7 +333,7 @@ nextTimer = &gba->timers[1];
 				if (GBATimerFlagsIsCountUp(nextTimer->flags)) {
 					++gba->memory.io[REG_TM1CNT_LO >> 1];
 					if (!gba->memory.io[REG_TM1CNT_LO >> 1]) {
-						nextTimer->nextEvent = 0;
+						nextTimer->nextEvent = cycles;
 					}
 				}
 			}

@@ -341,7 +341,7 @@ nextEvent = timer->nextEvent;
 		}
 
 		timer = &gba->timers[1];
-		if (GBATimerFlagsIsEnable(timer->flags)) {
+		if (GBATimerFlagsIsEnable(timer->flags) && timer->nextEvent != INT_MAX) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			if (timer->nextEvent <= 0) {

@@ -372,7 +372,7 @@ nextTimer = &gba->timers[2];
 				if (GBATimerFlagsIsCountUp(nextTimer->flags)) {
 					++gba->memory.io[REG_TM2CNT_LO >> 1];
 					if (!gba->memory.io[REG_TM2CNT_LO >> 1]) {
-						nextTimer->nextEvent = 0;
+						nextTimer->nextEvent = cycles;
 					}
 				}
 			}

@@ -382,7 +382,7 @@ }
 		}
 
 		timer = &gba->timers[2];
-		if (GBATimerFlagsIsEnable(timer->flags)) {
+		if (GBATimerFlagsIsEnable(timer->flags) && timer->nextEvent != INT_MAX) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			if (timer->nextEvent <= 0) {

@@ -403,7 +403,7 @@ nextTimer = &gba->timers[3];
 				if (GBATimerFlagsIsCountUp(nextTimer->flags)) {
 					++gba->memory.io[REG_TM3CNT_LO >> 1];
 					if (!gba->memory.io[REG_TM3CNT_LO >> 1]) {
-						nextTimer->nextEvent = 0;
+						nextTimer->nextEvent = cycles;
 					}
 				}
 			}

@@ -413,7 +413,7 @@ }
 		}
 
 		timer = &gba->timers[3];
-		if (GBATimerFlagsIsEnable(timer->flags)) {
+		if (GBATimerFlagsIsEnable(timer->flags) && timer->nextEvent != INT_MAX) {
 			timer->nextEvent -= cycles;
 			timer->lastEvent -= cycles;
 			if (timer->nextEvent <= 0) {
M src/gba/io.c → src/gba/io.c 
@@ -883,10 +883,16 @@ gba->timersEnabled = 0;
 	for (i = 0; i < 4; ++i) {
 		LOAD_16(gba->timers[i].reload, 0, &state->timers[i].reload);
 		LOAD_16(gba->timers[i].oldReload, 0, &state->timers[i].oldReload);
-		LOAD_32(gba->timers[i].lastEvent, 0, &state->timers[i].lastEvent);
-		LOAD_32(gba->timers[i].nextEvent, 0, &state->timers[i].nextEvent);
 		LOAD_32(gba->timers[i].overflowInterval, 0, &state->timers[i].overflowInterval);
 		LOAD_32(gba->timers[i].flags, 0, &state->timers[i].flags);
+		if (i > 0 && GBATimerFlagsIsCountUp(gba->timers[i].flags)) {
+			// Overwrite invalid values in savestate
+			gba->timers[i].lastEvent = 0;
+			gba->timers[i].nextEvent = INT_MAX;
+		} else {
+			LOAD_32(gba->timers[i].lastEvent, 0, &state->timers[i].lastEvent);
+			LOAD_32(gba->timers[i].nextEvent, 0, &state->timers[i].nextEvent);
+		}
 		LOAD_16(gba->memory.dma[i].reg, (REG_DMA0CNT_HI + i * 12), state->io);
 		LOAD_32(gba->memory.dma[i].nextSource, 0, &state->dma[i].nextSource);
 		LOAD_32(gba->memory.dma[i].nextDest, 0, &state->dma[i].nextDest);