mapper_066.c


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static void mapper_066_init(struct nes_state *state) {
	state->map.m066.prg_offset = 0;
	state->map.m066.chr_offset = 0;
}

static uint8_t mapper_066_prg_read(struct nes_state *state, uint32_t addr) {
	if(addr >= 0x8000) {
		uint32_t base = state->map.m066.prg_offset;
		return state->prg_rom[base + (addr - 0x8000)];
	}
	return 0;
}

static void mapper_066_prg_write(struct nes_state *state, uint32_t addr, uint8_t value) {
	if(addr >= 0x8000) {
		uint32_t prg_bank = (value >> 4) & 3;
		uint32_t chr_bank = (value >> 0) & 3;

		state->map.m066.prg_offset = prg_bank * 0x8000;
		state->map.m066.chr_offset = chr_bank * 0x2000;
	}
}

static uint8_t mapper_066_chr_read(struct nes_state *state, uint32_t addr) {
	return state->chr_rom[state->map.m066.chr_offset + addr];
}

static void mapper_066_chr_write(struct nes_state *state, uint32_t addr, uint8_t value) {
}

static uint8_t mapper_066_ciram_read(struct nes_state *state, uint32_t addr) {
	uint32_t mirrored = addr & 0x0fff;

	if(state->ines.mirroring == 0) { // Horizontal
		mirrored = (mirrored & 0x800) | (mirrored & 0x3ff);
	} else { // Vertical (default fallback)
		mirrored = mirrored & 0x7ff;
	}

	return state->ciram[mirrored];
}

static void mapper_066_ciram_write(struct nes_state *state, uint32_t addr, uint8_t value) {
	uint32_t mirrored = addr & 0x0fff;

	if(state->ines.mirroring == 0) {
		mirrored = (mirrored & 0x800) | (mirrored & 0x3ff);
	} else {
		mirrored = mirrored & 0x7ff;
	}

	state->ciram[mirrored] = value;
}

static void mapper_066_tick(struct nes_state *state) {
	// No IRQ or timing logic needed
}