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is_dma_restarting hack no longer needed

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This commit is contained in:
Lior Halphon 2022-01-12 14:12:55 +02:00
parent c4a14ac4db
commit ec012cf9f8
2 changed files with 3 additions and 15 deletions
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3
Core/gb.h
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@ -435,8 +435,7 @@ struct GB_gameboy_internal_s {
uint8_t last_dma_read; uint8_t last_dma_read;
uint16_t dma_current_src; uint16_t dma_current_src;
int16_t dma_cycles; int16_t dma_cycles;
bool is_dma_restarting; uint8_t last_opcode_read; /* Required to emulate HDMA reads from Exxx */
uint8_t last_opcode_read; /* Required to emulte HDMA reads from Exxx */
bool hdma_starting; bool hdma_starting;
); );

15
Core/memory.c
View File

@ -1459,13 +1459,6 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
return; return;
case GB_IO_DMA: case GB_IO_DMA:
if (GB_is_dma_active(gb)) {
/* This is not correct emulation, since we're not really delaying the second DMA.
One write that should have happened in the first DMA will not happen. However,
since that byte will be overwritten by the second DMA before it can actually be
read, it doesn't actually matter. */
gb->is_dma_restarting = true;
}
gb->dma_cycles = -3; gb->dma_cycles = -3;
gb->dma_current_dest = 0; gb->dma_current_dest = 0;
gb->dma_current_src = value << 8; gb->dma_current_src = value << 8;
@ -1688,7 +1681,7 @@ void GB_write_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
bool GB_is_dma_active(GB_gameboy_t *gb) bool GB_is_dma_active(GB_gameboy_t *gb)
{ {
return gb->dma_current_dest < 0xa1 || gb->is_dma_restarting; return gb->dma_current_dest < 0xa1;
} }
void GB_dma_run(GB_gameboy_t *gb) void GB_dma_run(GB_gameboy_t *gb)
@ -1696,13 +1689,9 @@ void GB_dma_run(GB_gameboy_t *gb)
if (gb->dma_current_dest >= 0xa1) return; if (gb->dma_current_dest >= 0xa1) return;
while (unlikely(gb->dma_cycles >= 4)) { while (unlikely(gb->dma_cycles >= 4)) {
gb->dma_cycles -= 4; gb->dma_cycles -= 4;
if (gb->dma_current_dest >= 0xa1) {
gb->is_dma_restarting = false;
break;
}
if (gb->dma_current_dest >= 0xa0) { if (gb->dma_current_dest >= 0xa0) {
gb->dma_current_dest++; gb->dma_current_dest++;
continue; break;
} }
if (gb->dma_current_src < 0xe000) { if (gb->dma_current_src < 0xe000) {
gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src); gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src);