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Simplified HDMA and fixed the reading of the HDMA5 register

This commit is contained in:
Lior Halphon 2017-02-08 21:58:15 +02:00
parent d5c9a52337
commit 4b6fda0cb6
1 changed files with 31 additions and 43 deletions
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74
Core/memory.c
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@ -155,18 +155,11 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
case GB_IO_PCM_12:
case GB_IO_PCM_34:
{
if (!gb->is_cgb) return 0xFF;
GB_sample_t dummy;
GB_apu_get_samples_and_update_pcm_regs(gb, &dummy);
}
case GB_IO_HDMA1:
case GB_IO_HDMA2:
case GB_IO_HDMA3:
case GB_IO_HDMA4:
if (!gb->is_cgb) {
return 0xFF;
}
/* Fall through */
/* Fall through */
case GB_IO_JOYP:
case GB_IO_TMA:
case GB_IO_LCDC:
@ -190,10 +183,8 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
case GB_IO_DIV:
return gb->div_cycles >> 8;
case GB_IO_HDMA5:
if (!gb->is_cgb) {
return 0xFF;
}
return (gb->io_registers[GB_IO_HDMA5] & 0x80) | ((gb->hdma_steps_left - 1) & 0x7F);
if (!gb->is_cgb) return 0xFF;
return ((gb->hdma_on || gb->hdma_on_hblank)? 0 : 0x80) | ((gb->hdma_steps_left - 1) & 0x7F);
case GB_IO_SVBK:
if (!gb->cgb_mode) {
return 0xFF;
@ -416,10 +407,6 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
case GB_IO_OBP1:
case GB_IO_WY:
case GB_IO_WX:
case GB_IO_HDMA1:
case GB_IO_HDMA2:
case GB_IO_HDMA3:
case GB_IO_HDMA4:
case GB_IO_SB:
case GB_IO_DMG_EMULATION_INDICATION:
gb->io_registers[addr & 0xFF] = value;
@ -547,7 +534,30 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
}
gb->io_registers[GB_IO_KEY1] = value;
return;
case GB_IO_HDMA1:
if (gb->is_cgb) {
gb->hdma_current_src &= 0xF0;
gb->hdma_current_src |= value << 8;
}
return;
case GB_IO_HDMA2:
if (gb->is_cgb) {
gb->hdma_current_src &= 0xFF00;
gb->hdma_current_src |= value & 0xF0;
}
return;
case GB_IO_HDMA3:
if (gb->is_cgb) {
gb->hdma_current_dest &= 0xF0;
gb->hdma_current_dest |= value << 8;
}
return;
case GB_IO_HDMA4:
if (gb->is_cgb) {
gb->hdma_current_dest &= 0x1F00;
gb->hdma_current_dest |= value & 0xF0;
}
return;
case GB_IO_HDMA5:
if ((value & 0x80) == 0 && gb->hdma_on_hblank) {
gb->hdma_on_hblank = false;
@ -556,8 +566,6 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
gb->hdma_on = (value & 0x80) == 0;
gb->hdma_on_hblank = (value & 0x80) != 0;
gb->io_registers[GB_IO_HDMA5] = value;
gb->hdma_current_src = (gb->io_registers[GB_IO_HDMA1] << 8) | (gb->io_registers[GB_IO_HDMA2] & 0xF0);
gb->hdma_current_dest = (gb->io_registers[GB_IO_HDMA3] << 8) | (gb->io_registers[GB_IO_HDMA4] & 0xF0);
gb->hdma_steps_left = (gb->io_registers[GB_IO_HDMA5] & 0x7F) + 1;
/* Todo: Verify this. Gambatte's DMA tests require this. */
if (gb->hdma_current_dest + (gb->hdma_steps_left << 4) > 0xFFFF) {
@ -663,29 +671,9 @@ void GB_hdma_run(GB_gameboy_t *gb)
if (!gb->hdma_on) return;
while (gb->hdma_cycles >= 8) {
gb->hdma_cycles -= 8;
// The CGB boot rom uses the dest in "absolute" space, while some games use it relative to VRAM.
// This "normalizes" the dest to the CGB address space.
gb->hdma_current_dest &= 0x1fff;
gb->hdma_current_dest |= 0x8000;
if ((gb->hdma_current_src < 0x8000 || (gb->hdma_current_src >= 0xa000 && gb->hdma_current_src < 0xe000))) {
for (uint8_t i = 0; i < 0x10; i++) {
GB_write_memory(gb, gb->hdma_current_dest + i, GB_read_memory(gb, gb->hdma_current_src + i));
}
}
else {
gb->halted = false;
}
gb->hdma_current_src += 0x10;
gb->hdma_current_dest += 0x10;
gb->io_registers[GB_IO_HDMA2] += 0x10;
if ((gb->io_registers[GB_IO_HDMA2] & 0xF0) == 0) {
gb->io_registers[GB_IO_HDMA1]++;
}
gb->io_registers[GB_IO_HDMA4] += 0x10;
if ((gb->io_registers[GB_IO_HDMA4] & 0xF0) == 0) {
gb->io_registers[GB_IO_HDMA3]++;
for (uint8_t i = 0; i < 0x10; i++) {
GB_write_memory(gb, 0x8000 | (gb->hdma_current_dest++ & 0x1FFF), GB_read_memory(gb, (gb->hdma_current_src++)));
}
if(--gb->hdma_steps_left == 0){