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static uint8_t mapper_default_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_default_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_default_prg_rom_write(struct nes_state *state, uint32_t addr, uint8_t value) { }
// static uint8_t mapper_default_prg_ram_read(struct nes_state *state, uint32_t addr) { return 0; }
// static void mapper_default_prg_ram_write(struct nes_state *state, uint32_t addr, uint8_t value) { }
// static void mapper_default_chr_write(struct nes_state *state, uint32_t addr, uint8_t value) { }
// static void mapper_default_tick(struct nes_state *state) { }
__attribute__((naked)) void mapper_default_prg_rom_write(struct nes_state *state, uint32_t addr, uint8_t value) {
__asm__ __volatile__("ret");
}
__attribute__((naked)) uint8_t mapper_default_prg_ram_read(struct nes_state *state, uint32_t addr) {
__asm__ __volatile__("xor %%al, %%al\n\t" "ret" : : : "al");
}
__attribute__((naked)) void mapper_default_prg_ram_write(struct nes_state *state, uint32_t addr, uint8_t value) {
__asm__ __volatile__("ret");
}
__attribute__((naked)) void mapper_default_chr_write(struct nes_state *state, uint32_t addr, uint8_t value) {
__asm__ __volatile__("ret");
}
__attribute__((naked)) void mapper_default_tick(struct nes_state *state) {
__asm__ __volatile__("ret");
}
#include "mapper_000_0.c"
#include "mapper_001_0.c"
#include "mapper_002_2.c"
#include "mapper_003_0.c"
#include "mapper_003_1.c"
#include "mapper_003_2.c"
#include "mapper_007_2.c"
#include "mapper_011_0.c"
#include "mapper_066_0.c"
#define MAPPER_ID(mapper, submapper) (((mapper) << 4) | (submapper))
static void (*mapper_table[4096])(struct nes_state *state) = {
[MAPPER_ID( 0, 0)] = mapper_000_0_init,
[MAPPER_ID( 1, 0)] = mapper_001_0_init,
[MAPPER_ID( 2, 2)] = mapper_002_2_init,
[MAPPER_ID( 3, 0)] = mapper_003_0_init,
[MAPPER_ID( 3, 1)] = mapper_003_1_init,
[MAPPER_ID( 3, 2)] = mapper_003_2_init,
[MAPPER_ID( 7, 2)] = mapper_007_2_init,
[MAPPER_ID(11, 0)] = mapper_011_0_init,
[MAPPER_ID(66, 0)] = mapper_066_0_init,
};
// NOTE(peter): The entries with 0x0 will always have to be supplied/set by the mapper!
static void mapper_reset(struct nes_state *state) {
state->mapper_function.prg_rom_read = 0x0;
state->mapper_function.prg_rom_write = mapper_default_prg_rom_write;
state->mapper_function.prg_ram_read = mapper_default_prg_ram_read;
state->mapper_function.prg_ram_write = mapper_default_prg_ram_write;
state->mapper_function.chr_read = 0x0;
state->mapper_function.chr_write = mapper_default_chr_write;
state->mapper_function.ciram_read = mapper_default_ciram_read;
state->mapper_function.ciram_write = mapper_default_ciram_write;
state->mapper_function.tick = 0;
}
static void mapper_setup(struct nes_state *state) {
uint32_t mapper = state->ines.mapper << 4 | state->ines.submapper;
printf("Mapper %d_%x requested.\n", state->ines.mapper, state->ines.submapper);
mapper_reset(state);
if(mapper_table[mapper]) {
mapper_table[mapper](state);
} else {
printf("Unsupported mapper %d_%x, falling back to NROM (mapper 0)\n", state->ines.mapper, state->ines.submapper);
mapper_table[0](state);
}
}
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