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OMA DMA improvements (WIP)

This commit is contained in:
Lior Halphon 2022-01-03 16:51:45 +02:00
parent 81e45b00b9
commit cd16431699
1 changed files with 51 additions and 11 deletions
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62
Core/memory.c
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@ -9,7 +9,6 @@ typedef enum {
GB_BUS_MAIN, /* In DMG: Cart and RAM. In CGB: Cart only */
GB_BUS_RAM, /* In CGB only. */
GB_BUS_VRAM,
GB_BUS_INTERNAL, /* Anything in highram. Might not be the most correct name. */
} bus_t;
static bus_t bus_for_addr(GB_gameboy_t *gb, uint16_t addr)
@ -23,10 +22,7 @@ static bus_t bus_for_addr(GB_gameboy_t *gb, uint16_t addr)
if (addr < 0xC000) {
return GB_BUS_MAIN;
}
if (addr < 0xFE00) {
return GB_is_cgb(gb)? GB_BUS_RAM : GB_BUS_MAIN;
}
return GB_BUS_INTERNAL;
return GB_is_cgb(gb)? GB_BUS_RAM : GB_BUS_MAIN;
}
static uint16_t bitwise_glitch(uint16_t a, uint16_t b, uint16_t c)
@ -255,7 +251,18 @@ void GB_trigger_oam_bug_read(GB_gameboy_t *gb, uint16_t address)
static bool is_addr_in_dma_use(GB_gameboy_t *gb, uint16_t addr)
{
if (!gb->dma_steps_left || (gb->dma_cycles < 0 && !gb->is_dma_restarting) || addr >= 0xFE00) return false;
if (!gb->dma_steps_left || (gb->dma_cycles < 0 && !gb->is_dma_restarting) || addr >= 0xfe00) return false;
if (addr >= 0xfe00) return false;
if (gb->dma_current_src == addr) return false; // Shortcut for DMA access flow
if (gb->dma_current_src > 0xe000 && (gb->dma_current_src & ~0x2000) == addr) return false;
if (GB_is_cgb(gb)) {
if (addr >= 0xe000) {
return bus_for_addr(gb, gb->dma_current_src) != GB_BUS_VRAM;
}
if (gb->dma_current_src >= 0xe000) {
return bus_for_addr(gb, addr) != GB_BUS_VRAM;
}
}
return bus_for_addr(gb, addr) == bus_for_addr(gb, gb->dma_current_src);
}
@ -732,7 +739,22 @@ uint8_t GB_read_memory(GB_gameboy_t *gb, uint16_t addr)
GB_debugger_test_read_watchpoint(gb, addr);
}
if (unlikely(is_addr_in_dma_use(gb, addr))) {
addr = gb->dma_current_src;
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 0xFF;
}
if (GB_is_cgb(gb) && bus_for_addr(gb, gb->dma_current_src) != GB_BUS_RAM && addr >= 0xc000) {
// TODO: this should probably affect the DMA dest as well
addr = (gb->dma_current_src & 0x1000) | (addr & 0xFFF) | 0xC000;
}
else if (GB_is_cgb(gb) && gb->dma_current_src >= 0xe000 && addr > 0xc000) {
// TODO: this should probably affect the DMA dest as well
addr = (gb->dma_current_src & 0x1000) | (addr & 0xFFF) | 0xC000;
}
else {
addr = gb->dma_current_src;
}
}
uint8_t data = read_map[addr >> 12](gb, addr);
GB_apply_cheat(gb, addr, &data);
@ -1631,8 +1653,22 @@ void GB_write_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
}
if (unlikely(is_addr_in_dma_use(gb, addr))) {
/* Todo: What should happen? Will this affect DMA? Will data be written? What and where? */
return;
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;
}
if (GB_is_cgb(gb) && bus_for_addr(gb, gb->dma_current_src) != GB_BUS_RAM && addr >= 0xc000) {
// TODO: this should probably affect the DMA dest as well
addr = (gb->dma_current_src & 0x1000) | (addr & 0xFFF) | 0xC000;
}
else if (GB_is_cgb(gb) && gb->dma_current_src >= 0xe000 && addr > 0xc000) {
// TODO: this should probably affect the DMA dest as well
addr = (gb->dma_current_src & 0x1000) | (addr & 0xFFF) | 0xC000;
}
else {
addr = gb->dma_current_src;
}
}
write_map[addr >> 12](gb, addr, value);
}
@ -1648,8 +1684,12 @@ void GB_dma_run(GB_gameboy_t *gb)
gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src);
}
else {
/* Todo: Not correct on the CGB */
gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src & ~0x2000);
if (GB_is_cgb(gb)) {
gb->oam[gb->dma_current_dest++] = 0xFF;
}
else {
gb->oam[gb->dma_current_dest++] = GB_read_memory(gb, gb->dma_current_src & ~0x2000);
}
}
/* dma_current_src must be the correct value during GB_read_memory */