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GBA Memory: Slightly simplify prefetch logic

This commit is contained in:
Vicki Pfau 2017-10-29 17:09:54 -07:00
parent 7b5a9b4f65
commit 1a71b8b11a
1 changed files with 8 additions and 9 deletions
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17
src/gba/memory.c
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@ -1499,9 +1499,11 @@ int32_t GBAMemoryStall(struct ARMCore* cpu, int32_t wait) {
int32_t previousLoads = 0; int32_t previousLoads = 0;
// Don't prefetch too much if we're overlapping with a previous prefetch // Don't prefetch too much if we're overlapping with a previous prefetch
uint32_t dist = (memory->lastPrefetchedPc - cpu->gprs[ARM_PC]) >> 1; uint32_t dist = (memory->lastPrefetchedPc - cpu->gprs[ARM_PC]);
if (dist < 8) { int32_t maxLoads = 8;
previousLoads = dist; if (dist < 16) {
previousLoads = dist >> 1;
maxLoads -= previousLoads;
} }
int32_t s = cpu->memory.activeSeqCycles16; int32_t s = cpu->memory.activeSeqCycles16;
@ -1511,12 +1513,9 @@ int32_t GBAMemoryStall(struct ARMCore* cpu, int32_t wait) {
int32_t stall = s; int32_t stall = s;
int32_t loads = 1; int32_t loads = 1;
if (stall < wait) { while (stall < wait && loads < maxLoads) {
int32_t maxLoads = 8 - previousLoads; stall += s;
while (stall < wait && loads < maxLoads) { ++loads;
stall += s;
++loads;
}
} }
if (stall > wait) { if (stall > wait) {
// The wait cannot take less time than the prefetch stalls // The wait cannot take less time than the prefetch stalls