32 lines
687 B
C
32 lines
687 B
C
#include "../include/mapper.h"
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#include "../include/rom.h"
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#include "../cpu/memory.h"
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#define PRG_BANK_SIZE 0x4000 // 16Kb
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byte *nrom_mem_read(address addr) {
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Rom *rom = rom_get();
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if (addr < PRG_BANK_SIZE || rom->prg_rom_size > PRG_BANK_SIZE) {
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return &rom->prg_rom[addr];
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}
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// The second bank is mirrored
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return &rom->prg_rom[addr - PRG_BANK_SIZE];
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}
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byte *nrom_ppu_read(address addr) {
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if (addr < 0x2000) {
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Rom *rom = rom_get();
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return &rom->chr_rom[addr];
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}
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return NULL;
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}
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Mapper get_simple_mapper() {
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Mapper mapper;
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mapper.mem_read = &nrom_mem_read;
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mapper.ppu_read = &nrom_ppu_read;
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return mapper;
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} |