diff options
Diffstat (limited to 'memory.c')
| -rw-r--r-- | memory.c | 24 |
1 files changed, 21 insertions, 3 deletions
@@ -7,10 +7,27 @@ static uint8_t memory_read(struct nes_state *restrict state, uint32_t offset) { ppu_tick(state); // apu_tick(state); - if(LIKELY(offset < 0x2000)) { + if(LIKELY(offset >= 0x6000)) { // MOST + return state->mapper.prg_read(state, offset); + + } else if(LIKELY(offset < 0x2000)) { // SECOND return state->ram[offset & 0x07ff]; - } else if(offset < 0x4000) { + } else if(offset < 0x4000) { // THIRD + return ppu_read(state, offset); + + } else if(offset == 0x4016 || offset == 0x4017) { + uint32_t index = offset & 1; + uint8_t value = (state->ppu.input_latch[index] >> state->ppu.input_bit[index]) & 1; + state->ppu.input_bit[index]++; + return value | 0x40; // Bit 6 open bus high, bit 7 low + } + +#if 0 + if(LIKELY(offset < 0x2000)) { // SECOND + return state->ram[offset & 0x07ff]; + + } else if(offset < 0x4000) { // THIRD return ppu_read(state, offset); } else if(offset == 0x4016 || offset == 0x4017) { @@ -23,10 +40,11 @@ static uint8_t memory_read(struct nes_state *restrict state, uint32_t offset) { // static uint32_t apuread = 0; // // printf("%.5d apu\n", apuread++); - } else if(LIKELY(offset >= 0x6000)) { + } else if(LIKELY(offset >= 0x6000)) { // MOST return state->mapper.prg_read(state, offset); } +#endif return 0; } |