108 lines
2.1 KiB
C
108 lines
2.1 KiB
C
#include "cartridge.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include "bus.h"
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struct INES_Header
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{
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Byte nestext[4];
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Byte prg_rom_size;
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Byte chr_rom_size;
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struct
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{
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Byte mirror : 1;
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Byte battery : 1;
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Byte trainer : 1;
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Byte ignore_mirror : 1;
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Byte mapper_lower_nibble : 4;
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} Flags6;
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struct
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{
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Byte vs : 1;
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Byte playchoice : 1;
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Byte nes20 : 2;
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Byte mapper_upper_nibble : 4;
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} Flags7;
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Byte prg_ram_size;
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Byte unused[7];
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};
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struct Cartridge* createCartridge(struct Bus* parent, const char* filepath)
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{
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struct Cartridge* cartridge = (struct Cartridge*)malloc(sizeof(struct Cartridge));
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if (cartridge == NULL)
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{
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fprintf(stderr, "Failed to create cartridge.\n");
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exit(1);
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}
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FILE* fp = fopen(filepath, "rb");
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struct INES_Header header;
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fread(&header, sizeof(header), 1, fp);
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cartridge->prg_rom = (Byte*)malloc(0x4000 * (size_t)header.prg_rom_size);
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if (cartridge->prg_rom == NULL)
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{
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fprintf(stderr, "Failed to allocate PRG memory for cartridge, aborting.\n");
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exit(1);
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}
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cartridge->chr_rom = (Byte*)malloc(0x2000 * (size_t)header.chr_rom_size);
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if (cartridge->chr_rom == NULL)
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{
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fprintf(stderr, "Failed to allocate CHR memory for cartridge, aborting.\n");
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exit(1);
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}
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fread(cartridge->prg_rom, 0x4000, header.prg_rom_size, fp);
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fread(cartridge->chr_rom, 0x2000, header.chr_rom_size, fp);
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cartridge->bus = parent;
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return cartridge;
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}
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void destroyCartridge(struct Cartridge* cartridge)
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{
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free(cartridge->chr_rom);
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free(cartridge->prg_rom);
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free(cartridge);
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}
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Byte readCartridge(struct Cartridge* cartridge, Word addr)
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{
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// TODO: Force M000 mapper for now
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Byte val = 0;
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if (0x6000 <= addr && addr <= 0x7FFF) // PRG RAM
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{
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// do nothing for now
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}
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else if (0x8000 <= addr && addr <= 0xFFFF) // PRG ROM
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{
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val = cartridge->prg_rom[addr & 0x1FFF];
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}
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return val;
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}
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void writeCartridge(struct Cartridge* cartridge, Word addr, Byte val)
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{
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// TODO: Force M000 mapper for now
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if (0x6000 <= addr && addr <= 0x7FFF) // PRG RAM
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{
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// do nothing for now
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}
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else if (0x8000 <= addr && addr <= 0xFFFF) // PRG ROM
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{
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cartridge->prg_rom[addr & 0x1FFF] = val;
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}
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}
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