mapper_001.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46


static void mapper_001_init(struct nes_state *state) {
	// Nothing to initialize for 001
}

static uint8_t mapper_001_prg_read(struct nes_state *state, uint32_t addr) {
	uint32_t prg_size = state->ines.prg_size;

	uint32_t mask = (state->ines.prg_size == 16384) ? 0x3fff : 0x7fff;
	return state->prg_rom[addr & mask];
}

static void mapper_001_prg_write(struct nes_state *state, uint32_t addr, uint8_t value) {
}

static uint8_t mapper_001_chr_read(struct nes_state *state, uint32_t addr) {
	return state->chr_rom[addr];
}

static void mapper_001_chr_write(struct nes_state *state, uint32_t addr, uint8_t value) {
}

static uint8_t mapper_001_ciram_read(struct nes_state *state, uint32_t addr) {
	if(state->ines.mirroring == 0) { // Horizontal
		addr = (addr & 0x800) | (addr & 0x3ff);
	} else { // Vertical (default fallback)
		addr = addr & 0x7ff;
	}

	return state->ciram[addr];
}

static void mapper_001_ciram_write(struct nes_state *state, uint32_t addr, uint8_t value) {
	if(state->ines.mirroring == 0) {
		addr = (addr & 0x800) | (addr & 0x3ff);
	} else {
		addr = addr & 0x7ff;
	}

	state->ciram[addr] = value;
}

static void mapper_001_tick(struct nes_state *state) {
}