73 lines
1.7 KiB
C++
73 lines
1.7 KiB
C++
#include "ppu.hpp"
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#include "mapper.hpp"
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Mapper::Mapper(u8* rom) : rom(rom)
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{
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// Read infos from header:
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prgSize = rom[4] * 0x4000;
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chrSize = rom[5] * 0x2000;
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prgRamSize = rom[8] ? rom[8] * 0x2000 : 0x2000;
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set_mirroring((rom[6] & 1) ? PPU::VERTICAL : PPU::HORIZONTAL);
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this->prg = rom + 16;
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this->prgRam = new u8[prgRamSize];
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// CHR ROM:
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if (chrSize)
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this->chr = rom + 16 + prgSize;
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// CHR RAM:
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else
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{
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chrRam = true;
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chrSize = 0x2000;
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this->chr = new u8[chrSize];
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}
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}
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Mapper::~Mapper()
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{
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delete rom;
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delete prgRam;
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if (chrRam)
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delete chr;
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}
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/* Access to memory */
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u8 Mapper::read(u16 addr)
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{
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if (addr >= 0x8000)
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return prg[prgMap[(addr - 0x8000) / 0x2000] + ((addr - 0x8000) % 0x2000)];
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else
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return prgRam[addr - 0x6000];
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}
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u8 Mapper::chr_read(u16 addr)
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{
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return chr[chrMap[addr / 0x400] + (addr % 0x400)];
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}
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/* PRG mapping functions */
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template <int pageKBs> void Mapper::map_prg(int slot, int bank)
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{
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if (bank < 0)
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bank = (prgSize / (0x400*pageKBs)) + bank;
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for (int i = 0; i < (pageKBs/8); i++)
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prgMap[(pageKBs/8) * slot + i] = (pageKBs*0x400*bank + 0x2000*i) % prgSize;
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}
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template void Mapper::map_prg<32>(int, int);
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template void Mapper::map_prg<16>(int, int);
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template void Mapper::map_prg<8> (int, int);
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/* CHR mapping functions */
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template <int pageKBs> void Mapper::map_chr(int slot, int bank)
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{
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for (int i = 0; i < pageKBs; i++)
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chrMap[pageKBs*slot + i] = (pageKBs*0x400*bank + 0x400*i) % chrSize;
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}
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template void Mapper::map_chr<8>(int, int);
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template void Mapper::map_chr<4>(int, int);
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template void Mapper::map_chr<2>(int, int);
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template void Mapper::map_chr<1>(int, int);
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