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MEMORY.c
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MEMORY.c
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#include "memory.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static const uint8_t defaultROM[0x8000] = {
#include "tetris.rom"
};
static const struct {
bool battery;
uint8_t mbcGen;
char type[20];
} mbcTypes[] = {
{false, 0, "NO MBC" }, {false, 1, "MBC1" }, {false, 1, "MBC1" }, {true , 1, "MBC1+BATTERY" }, {false, 0, "UNKNOWN" },
{false, 2, "MBC2" }, {true , 2, "MBC2+BATTERY" }, {false, 0, "UNKNOWN" }, {false, 0, "NO MBC" }, {true , 0, "BATTERY" },
{false, 0, "UNKNOWN" }, {false, 1, "MMM01" }, {false, 1, "MMM01" }, {true , 1, "MMM01+BATTERY"}, {false, 0, "UNKNOWN" },
{true , 3, "MBC3+RTC+BATTERY" }, {true , 3, "MBC3+RTC+BATTERY"}, {false, 3, "MBC3" }, {true , 3, "MBC3" }, {false, 3, "MBC3+BATTERY"},
{false, 0, "UNKNOWN" }, {false, 0, "UNKNOWN" }, {false, 0, "UNKNOWN" }, {false, 0, "UNKNOWN" }, {false, 0, "UNKNOWN" },
{false, 5, "MBC5" }, {false, 5, "MBC5" }, {true , 5, "MBC5+BATTERY"}, {false, 5, "MBC5+RUMBLE" }, {false, 5, "MBC5+RUMBLE" },
{true , 5, "MBC5+RUMBLE+BATTERY"}, {false, 0, "UNKNOWN" }, {false, 6, "MBC6" },
};
Memory* initMemory(const char *path, const uint8_t hackLevel) {
Memory *mem = calloc(1, sizeof(Memory));
mem->currROMBank = 1;
mem->IO[0] = 0xFF;
memset(&mem->IO[0x4C], 0xFF, sizeof(mem->IO) - 0x4C);
mem->IO[0x50] = 0;
{
FILE *file = fopen(path, "rb");
if (file) {
fseek(file, 0, SEEK_END);
mem->nbROMBanks = ftell(file) / ROM_BANK_SIZE;
mem->romBanks = malloc(mem->nbROMBanks * ROM_BANK_SIZE);
rewind(file);
uint16_t matched = 0;
for (uint16_t i = 0; i < mem->nbROMBanks; i++) {
fread(mem->romBanks[i], 1, ROM_BANK_SIZE, file);
// Replace busy waits with more efficient code
if (hackLevel >= 2) {
for (uint16_t j = 0; j < ROM_BANK_SIZE; j++) {
if (mem->romBanks[i][j] == 0xF0 && mem->romBanks[i][j + 1] != 0xCC && (mem->romBanks[i][j + 2] == 0xA7 || mem->romBanks[i][j + 2] == 0xB7) && mem->romBanks[i][j + 3] == 0x28 && mem->romBanks[i][j + 4] == 0xFB) {
mem->romBanks[i][j + 3] = 0xD3;
mem->romBanks[i][j + 4] = mem->romBanks[i][j + 1];
mem->romBanks[i][j + 0] = 0x00;
mem->romBanks[i][j + 1] = 0x00;
mem->romBanks[i][j + 2] = 0x00;
} else if (mem->romBanks[i][j] == 0xFA && (mem->romBanks[i][j + 3] == 0xA7 || mem->romBanks[i][j + 3] == 0xB7) && mem->romBanks[i][j + 4] == 0x28 && mem->romBanks[i][j + 5] == 0xFA) {
mem->romBanks[i][j + 3] = 0xDD;
mem->romBanks[i][j + 4] = mem->romBanks[i][j + 1];
mem->romBanks[i][j + 5] = mem->romBanks[i][j + 2];
mem->romBanks[i][j + 0] = 0x00;
mem->romBanks[i][j + 1] = 0x00;
mem->romBanks[i][j + 2] = 0x00;
} else if (mem->romBanks[i][j] == 0xBE && mem->romBanks[i][j + 1] == 0x20 && mem->romBanks[i][j + 2] == 0xFD) {
mem->romBanks[i][j + 2] = 0xDB;
mem->romBanks[i][j ] = 0x00;
mem->romBanks[i][j + 1] = 0x00;
} else if (hackLevel >= 3) {
int8_t k = 0;
if (mem->romBanks[i][j + k] == 0xBE) k += 1;
else if (mem->romBanks[i][j + k] == 0xF0 && mem->romBanks[i][j + k + 1] >= 0x40 && mem->romBanks[i][j + k + 1] != 0xCC) k += 2;
else if (mem->romBanks[i][j + k] == 0xFA) k += 3;
else continue;
if (k > 1) {
if (mem->romBanks[i][j + k] >= 0xA0 && mem->romBanks[i][j + k] <= 0xBF) k += 1;
else if (mem->romBanks[i][j + k] == 0xE6 || mem->romBanks[i][j + k] == 0xF6 || mem->romBanks[i][j + k] == 0xEE || mem->romBanks[i][j + k] == 0xFE) k += 2;
else continue;
}
if (mem->romBanks[i][j + k] == 0x20 || mem->romBanks[i][j + k] == 0x28 || mem->romBanks[i][j + k] == 0x30 || mem->romBanks[i][j + k] == 0x38) k += 1;
else continue;
if ((int8_t)mem->romBanks[i][j + k] == -(k + 1)) {
mem->patchMem[matched] = 0xF4;
memcpy(&mem->patchMem[matched + 1], &mem->romBanks[i][j], k);
mem->patchMem[matched + k + 1] = mem->romBanks[i][j + k] - 1;
mem->patchMem[matched + k + 2] = 0xC3;
const uint16_t returnAddress = j + 3 + (i > 0 ? ROM_BANK_SIZE : 0);
mem->patchMem[matched + k + 3] = returnAddress & 0xFF;
mem->patchMem[matched + k + 4] = returnAddress >> 8;
mem->romBanks[i][j] = 0xC3;
mem->romBanks[i][j + 1] = matched & 0xFF;
mem->romBanks[i][j + 2] = 0xE0 | matched >> 8;
memset(&mem->romBanks[i][j + 3], 0, k - 2);
matched += k + 5;
printf("%02u %04X %4X\t", i, j, matched);
}
}
}
}
}
fclose(file);
// exit(205);
} else {
printf("Failed to open '%s'\n", path);
mem->nbROMBanks = sizeof(defaultROM) / ROM_BANK_SIZE;
mem->romBanks = malloc(mem->nbROMBanks * ROM_BANK_SIZE);
for (uint16_t i = 0; i < mem->nbROMBanks; i++)
memcpy(mem->romBanks[i], defaultROM + i * ROM_BANK_SIZE, ROM_BANK_SIZE);
}
}
const uint8_t mbcType = mem->romBanks[0][0x147];
if (mbcType > ARRAY_SIZE(mbcTypes)) {
printf("Unsupported MBC (%02X)\n", mbcType);
memset(mem->romBanks, 0xFF, ROM_BANK_SIZE);
return mem;
}
mem->mbcGen = mbcTypes[mbcType].mbcGen;
const uint8_t ram = mem->mbcGen == 2 ? 8 : 2 << (mem->romBanks[0][0x149] << 1) >> 2;
const uint16_t romSize = 1 << (mem->romBanks[0][0x148] + 5);
assert(mem->nbROMBanks == (romSize << 10) / ROM_BANK_SIZE);
printf("%s - %dk ROM", mbcTypes[mbcType].type, romSize);
if (ram) printf(" - %dk RAM", ram);
putchar('\n');
mem->nbRAMBanks = (ram << 10) / RAM_SIZE;
assert(mem->nbRAMBanks <= 4);
mem->externalRAM = calloc(mem->nbRAMBanks, RAM_SIZE);
if (mbcTypes[mbcType].battery) {
assert(ram > 0);
strcpy(mem->savePath, path);
char *dot = strchr(mem->savePath, '.');
if (dot) *dot = '\0';
strcat(mem->savePath, ".sav");
FILE *file = fopen(mem->savePath, "rb");
if (file) {
for (uint8_t i = 0; i < mem->nbRAMBanks; i++)
fread(&mem->externalRAM[i], 1, RAM_SIZE, file);
fclose(file);
}
}
return mem;
}
void deleteMemory(Memory *mem) {
if (mbcTypes[mem->romBanks[0][0x147]].battery) {
FILE *file = fopen(mem->savePath, "wb");
if (file) {
for (uint8_t i = 0; i < mem->nbRAMBanks; i++)
fwrite(mem->externalRAM[i], 1, RAM_SIZE, file);
fclose(file);
}
}
free(mem->externalRAM);
free(mem->romBanks);
}