133 lines
2.4 KiB
C++
133 lines
2.4 KiB
C++
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/////////////////////////////////////////////////////////////////////
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// Mapper 68
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void NES_mapper68::Reset()
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{
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// set CPU bank pointers
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set_CPU_banks(0,1,num_8k_ROM_banks-2,num_8k_ROM_banks-1);
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regs[0] = 0;
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regs[1] = 0;
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regs[2] = 0;
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regs[3] = 0;
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}
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void NES_mapper68::MemoryWrite(uint32 addr, uint8 data)
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{
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switch(addr & 0xF000)
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{
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case 0x8000:
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{
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set_PPU_bank0(data*2+0);
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set_PPU_bank1(data*2+1);
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}
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break;
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case 0x9000:
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{
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set_PPU_bank2(data*2+0);
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set_PPU_bank3(data*2+1);
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}
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break;
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case 0xA000:
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{
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set_PPU_bank4(data*2+0);
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set_PPU_bank5(data*2+1);
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}
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break;
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case 0xB000:
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{
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set_PPU_bank6(data*2+0);
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set_PPU_bank7(data*2+1);
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}
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break;
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case 0xC000:
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{
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regs[2] = data;
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SyncMirror();
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}
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break;
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case 0xD000:
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{
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regs[3] = data;
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SyncMirror();
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}
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break;
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case 0xE000:
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{
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regs[0] = (data & 0x10) >> 4;
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regs[1] = data & 0x03;
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SyncMirror();
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}
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break;
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case 0xF000:
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{
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set_CPU_bank4(data*2);
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set_CPU_bank5(data*2+1);
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}
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break;
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}
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}
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void NES_mapper68::SyncMirror()
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{
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if(regs[0])
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{
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if (regs[1] == 0)
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{
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set_PPU_bank8(regs[2] + 0x80); // + 0x20000
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set_PPU_bank9(regs[3] + 0x80);
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set_PPU_bank10(regs[2] + 0x80);
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set_PPU_bank11(regs[3] + 0x80);
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}
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else if (regs[1] == 1)
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{
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set_PPU_bank8(regs[2] + 0x80);
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set_PPU_bank9(regs[2] + 0x80);
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set_PPU_bank10(regs[3] + 0x80);
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set_PPU_bank11(regs[3] + 0x80);
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}
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else if (regs[1] == 2)
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{
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set_PPU_bank8(regs[2] + 0x80);
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set_PPU_bank9(regs[2] + 0x80);
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set_PPU_bank10(regs[2] + 0x80);
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set_PPU_bank11(regs[2] + 0x80);
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}
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else if (regs[1] == 3)
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{
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set_PPU_bank8(regs[3] + 0x80);
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set_PPU_bank9(regs[3] + 0x80);
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set_PPU_bank10(regs[3] + 0x80);
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set_PPU_bank11(regs[3] + 0x80);
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}
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}
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else
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{
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if (regs[1] == 0)
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{
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set_mirroring(NES_PPU::MIRROR_VERT);
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}
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else if (regs[1] == 1)
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{
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set_mirroring(NES_PPU::MIRROR_HORIZ);
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}
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else if (regs[1] == 2)
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{
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set_mirroring(0,0,0,0);
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}
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else if (regs[1] == 3)
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{
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set_mirroring(1,1,1,1);
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}
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}
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}
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/////////////////////////////////////////////////////////////////////
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