mappers/mapper_003_1.c


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static uint8_t mapper_003_1_prg_rom_read(struct nes_state *state, uint32_t addr) {
	return state->prg_rom[addr & 0x7fff];
}

static void mapper_003_1_prg_rom_write(struct nes_state *state, uint32_t addr, uint8_t value) {
	struct mapper_003_1 *mapper = &state->mapper_data.m003_1;

	if(addr >= 0x8000) {
		mapper->chr_ptr = state->chr_rom + (value & 3) * 0x2000;
	}
}

static uint8_t mapper_003_1_chr_read(struct nes_state *state, uint32_t addr) {
	struct mapper_003_1 *mapper = &state->mapper_data.m003_1;
	return mapper->chr_ptr[addr];
}

static void mapper_003_1_init(struct nes_state *state) {
	struct mapper_003_1 *mapper = &state->mapper_data.m003_1;

	mapper->chr_ptr = state->chr_rom;

	state->mapper_function.prg_rom_read	= mapper_003_1_prg_rom_read;
	state->mapper_function.prg_rom_write	= mapper_003_1_prg_rom_write;
	state->mapper_function.chr_read	= mapper_003_1_chr_read;
}