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GBA Timer: Fix timer regression when prefetch is enabled (fixes #781)

This commit is contained in:
Vicki Pfau 2017-07-08 17:04:05 -07:00
parent 4c439e3819
commit fc2a0955f4
2 changed files with 4 additions and 8 deletions
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8
src/gba/io.c
View File

@ -709,16 +709,16 @@ uint16_t GBAIORead(struct GBA* gba, uint32_t address) {
switch (address) {
// Reading this takes two cycles (1N+1I), so let's remove them preemptively
case REG_TM0CNT_LO:
GBATimerUpdateRegister(gba, 0, 2);
GBATimerUpdateRegister(gba, 0, 4);
break;
case REG_TM1CNT_LO:
GBATimerUpdateRegister(gba, 1, 2);
GBATimerUpdateRegister(gba, 1, 4);
break;
case REG_TM2CNT_LO:
GBATimerUpdateRegister(gba, 2, 2);
GBATimerUpdateRegister(gba, 2, 4);
break;
case REG_TM3CNT_LO:
GBATimerUpdateRegister(gba, 3, 2);
GBATimerUpdateRegister(gba, 3, 4);
break;
case REG_KEYINPUT:

4
src/gba/timer.c
View File

@ -143,10 +143,6 @@ void GBATimerUpdateRegister(struct GBA* gba, int timer, int32_t cyclesLate) {
return;
}
if (gba->memory.lastPrefetchedPc > (uint32_t) gba->cpu->gprs[ARM_PC]) {
cyclesLate -= ((gba->memory.lastPrefetchedPc - gba->cpu->gprs[ARM_PC]) * gba->cpu->memory.activeSeqCycles16) / WORD_SIZE_THUMB;
}
int prescaleBits = GBATimerFlagsGetPrescaleBits(currentTimer->flags);
int32_t currentTime = mTimingCurrentTime(&gba->timing) - cyclesLate;
int32_t tickMask = (1 << prescaleBits) - 1;