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More DMA write conflicts

This commit is contained in:
Lior Halphon 2022-01-05 21:40:10 +02:00
parent 5e7bb0f891
commit ab1d4cd26e
2 changed files with 21 additions and 10 deletions
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3
Core/gb.h
View File

@ -436,7 +436,8 @@ struct GB_gameboy_internal_s {
uint16_t dma_current_src;
int16_t dma_cycles;
bool is_dma_restarting;
bool dma_write_zero;
uint8_t dma_and_pattern;
bool dma_skip_write;
uint8_t last_opcode_read; /* Required to emulte HDMA reads from Exxx */
bool hdma_starting;
);

28
Core/memory.c
View File

@ -1466,6 +1466,7 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
read, it doesn't actually matter. */
gb->is_dma_restarting = true;
}
gb->dma_and_pattern = 0xFF;
gb->dma_cycles = -7;
gb->dma_current_dest = 0;
gb->dma_current_src = value << 8;
@ -1654,6 +1655,7 @@ void GB_write_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
}
if (unlikely(is_addr_in_dma_use(gb, addr))) {
bool oam_write = addr >= 0xFE00;
if (GB_is_cgb(gb) && bus_for_addr(gb, addr) == GB_BUS_MAIN && gb->dma_current_src >= 0xe000) {
/* This is cart specific! Everdrive 7X on a CGB-A or 0 behaves differently. */
return;
@ -1670,9 +1672,16 @@ void GB_write_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
else {
addr = gb->dma_current_src;
}
if (GB_is_cgb(gb)) {
gb->dma_write_zero = true;
if (gb->model < GB_MODEL_CGB_E) return;
if (GB_is_cgb(gb) || addr > 0xc000) {
gb->dma_and_pattern = addr < 0xc000? 0x00 : 0xFF;
if ((gb->model < GB_MODEL_CGB_0 || gb->model == GB_MODEL_CGB_B) && addr > 0xc000) {
gb->dma_and_pattern = value;
}
else if ((gb->model < GB_MODEL_CGB_C || gb->model > GB_MODEL_CGB_E) && addr > 0xc000 && !oam_write) {
gb->dma_skip_write = true;
gb->oam[gb->dma_current_dest] = value;
}
if (gb->model < GB_MODEL_CGB_E || addr >= 0xc000) return;
}
}
write_map[addr >> 12](gb, addr, value);
@ -1684,21 +1693,22 @@ void GB_dma_run(GB_gameboy_t *gb)
/* Todo: measure this value */
gb->dma_cycles -= 4;
gb->dma_steps_left--;
if (unlikely(gb->dma_write_zero)) {
gb->oam[gb->dma_current_dest++] = 0;
gb->dma_write_zero = false;
if (gb->dma_skip_write) {
gb->dma_skip_write = false;
gb->dma_current_dest++;
}
else 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) & gb->dma_and_pattern;
}
else {
if (GB_is_cgb(gb)) {
gb->oam[gb->dma_current_dest++] = 0xFF;
gb->oam[gb->dma_current_dest++] = gb->dma_and_pattern;
}
else {
gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src & ~0x2000);
gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src & ~0x2000) & gb->dma_and_pattern;
}
}
gb->dma_and_pattern = 0xFF;
/* dma_current_src must be the correct value during GB_read_memory */
gb->dma_current_src++;