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GBA Timer: More questionable tweaks

This commit is contained in:
Vicki Pfau 2017-07-05 21:22:47 -07:00
parent c7630a13da
commit d3678471f6
1 changed files with 7 additions and 5 deletions
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12
src/gba/timer.c
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@ -9,6 +9,8 @@
#include <mgba/internal/gba/io.h> #include <mgba/internal/gba/io.h>
#define TIMER_IRQ_DELAY 7 #define TIMER_IRQ_DELAY 7
#define TIMER_RELOAD_DELAY 0
#define TIMER_STARTUP_DELAY 2
static void GBATimerIrq(struct GBA* gba, int timerId) { static void GBATimerIrq(struct GBA* gba, int timerId) {
struct GBATimer* timer = &gba->timers[timerId]; struct GBATimer* timer = &gba->timers[timerId];
@ -157,7 +159,7 @@ void GBATimerUpdateRegister(struct GBA* gba, int timer, int32_t cyclesLate) {
if (!mTimingIsScheduled(&gba->timing, &currentTimer->event)) { if (!mTimingIsScheduled(&gba->timing, &currentTimer->event)) {
tickIncrement = (0x10000 - tickIncrement) << prescaleBits; tickIncrement = (0x10000 - tickIncrement) << prescaleBits;
currentTime -= mTimingCurrentTime(&gba->timing) - cyclesLate; currentTime -= mTimingCurrentTime(&gba->timing) - cyclesLate;
mTimingSchedule(&gba->timing, &currentTimer->event, tickIncrement + currentTime); mTimingSchedule(&gba->timing, &currentTimer->event, TIMER_RELOAD_DELAY + tickIncrement + currentTime);
} }
} }
@ -194,14 +196,14 @@ void GBATimerWriteTMCNT_HI(struct GBA* gba, int timer, uint16_t control) {
mTimingDeschedule(&gba->timing, &currentTimer->event); mTimingDeschedule(&gba->timing, &currentTimer->event);
gba->memory.io[(REG_TM0CNT_LO + (timer << 2)) >> 1] = currentTimer->reload; gba->memory.io[(REG_TM0CNT_LO + (timer << 2)) >> 1] = currentTimer->reload;
int32_t tickMask = (1 << prescaleBits) - 1; int32_t tickMask = (1 << prescaleBits) - 1;
currentTimer->lastEvent = (mTimingCurrentTime(&gba->timing)) & ~tickMask; currentTimer->lastEvent = (mTimingCurrentTime(&gba->timing) - TIMER_STARTUP_DELAY) & ~tickMask;
GBATimerUpdateRegister(gba, timer, 0); GBATimerUpdateRegister(gba, timer, TIMER_STARTUP_DELAY);
} else if (wasEnabled && !GBATimerFlagsIsEnable(currentTimer->flags)) { } else if (wasEnabled && !GBATimerFlagsIsEnable(currentTimer->flags)) {
mTimingDeschedule(&gba->timing, &currentTimer->event); mTimingDeschedule(&gba->timing, &currentTimer->event);
} else if (GBATimerFlagsIsEnable(currentTimer->flags) && GBATimerFlagsGetPrescaleBits(currentTimer->flags) != oldPrescale && !GBATimerFlagsIsCountUp(currentTimer->flags)) { } else if (GBATimerFlagsIsEnable(currentTimer->flags) && GBATimerFlagsGetPrescaleBits(currentTimer->flags) != oldPrescale && !GBATimerFlagsIsCountUp(currentTimer->flags)) {
mTimingDeschedule(&gba->timing, &currentTimer->event); mTimingDeschedule(&gba->timing, &currentTimer->event);
int32_t tickMask = (1 << prescaleBits) - 1; int32_t tickMask = (1 << prescaleBits) - 1;
currentTimer->lastEvent = (mTimingCurrentTime(&gba->timing)) & ~tickMask; currentTimer->lastEvent = (mTimingCurrentTime(&gba->timing) - TIMER_STARTUP_DELAY) & ~tickMask;
GBATimerUpdateRegister(gba, timer, 0); GBATimerUpdateRegister(gba, timer, TIMER_STARTUP_DELAY);
} }
} }