Rearrangement and refactoring and optimizations and more accuracy

1 files changed, 102 insertions, 0 deletions

diff --git a/mknes_memory.c b/mknes_memory.c
new file mode 100644
index 0000000..a27fa04
--- /dev/null
+++ b/mknes_memory.c
@@ -0,0 +1,102 @@
+__attribute__((hot))
+static inline uint8_t memory_read(struct nes_state *state, uint32_t offset) {
+	state->cpu.cycles++;
+	ppu_tick(state);
+	apu_tick(state);
+
+	if(offset <= 0x1fff) {
+		return state->ram[offset & 0x07ff];
+	}
+
+	if(offset >= 0x8000) {
+		return state->mapper_function.prg_rom_read(state, offset);
+	}
+
+	if(offset >= 0x2000 && offset <= 0x3fff) {
+		return ppu_read(state, offset);
+	}
+
+	if(offset == 0x4015) {
+		return apu_read4015(state);
+	}
+
+	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(offset >= 0x6000 && offset <= 0x7fff) {
+		return state->mapper_function.prg_ram_read(state, offset);
+	}
+
+	return 0;
+}
+
+
+__attribute__((hot))
+static inline uint8_t memory_read_dummy(struct nes_state *state, uint32_t offset) {
+	state->cpu.cycles++;
+	ppu_tick(state);
+	apu_tick(state);
+
+	if(offset >= 0x2000 && offset < 0x4000) {
+		return ppu_read(state, offset);
+	}
+	return 0;
+}
+
+
+__attribute__((hot, optimize("no-jump-tables")))
+static inline void memory_write(struct nes_state *state, uint32_t offset, uint8_t value) {
+	state->cpu.cycles++;
+	ppu_tick(state);
+	apu_tick(state);
+
+	if(offset <= 0x1fff) {
+		state->ram[offset & 0x07ff] = value;
+	}
+
+	if(offset >= 0x2000 && offset <= 0x3fff) {
+		ppu_write(state, offset, value);
+	}
+
+	if(offset >= 0x4000 && offset <= 0x4017) {
+		if(offset == 0x4014) {
+			ppu_dma_4014(state, value);
+		}
+
+		if(offset == 0x4016) {
+			uint8_t s = value & 1;
+			uint8_t prev = state->ppu.input_strobe;
+			state->ppu.input_strobe = s;
+
+			if(prev == 1 && s == 0) {
+					state->ppu.input_latch[0] = state->ppu.input[0];
+					state->ppu.input_latch[1] = state->ppu.input[1];
+					state->ppu.input_bit[0] = 0;
+					state->ppu.input_bit[1] = 0;
+			}
+		}
+
+		if(offset != 0x4014 && offset != 0x4016) {
+			apu_write(state, offset, value);
+		}
+	}
+
+	if(offset >= 0x6000 && offset <= 0x7fff) {
+		state->mapper_function.prg_ram_write(state, offset, value);
+	}
+
+	if(offset >= 0x8000) {
+		state->mapper_function.prg_rom_write(state, offset, value);
+	}
+
+}
+
+__attribute__((hot, flatten))
+static inline uint8_t memory_read_dma(struct nes_state *state, uint32_t offset) {
+	// NOTE(peter): DO NOT tick CPU/PPU/APU — caller handles timing
+	return state->ram[offset & 0x07ff];
+}