110 lines
2.3 KiB
C++
110 lines
2.3 KiB
C++
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/////////////////////////////////////////////////////////////////////
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// Mapper 235
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void NES_mapper235::Reset()
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{
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// set dummy data for open bus
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for(uint32 i = 0; i < 0x2000; i++)
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{
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dummy[i] = 0xFF;
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}
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// set CPU bank pointers
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set_CPU_banks(0,1,2,3);
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}
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void NES_mapper235::MemoryWrite(uint32 addr, uint8 data)
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{
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uint8 prg_bank = ((addr & 0x0300) >> 3) | (addr & 0x001F);
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uint8 open_bus = 0;
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if (num_8k_ROM_banks == 64*2)
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{
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// 100-in-1
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switch (addr & 0x0300)
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{
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case 0x0000: break;
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case 0x0100: open_bus = 1; break;
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case 0x0200: open_bus = 1; break;
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case 0x0300: open_bus = 1; break;
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}
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}
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else if (num_8k_ROM_banks == 128*2)
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{
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// 150-in-1
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switch (addr & 0x0300)
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{
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case 0x0000: break;
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case 0x0100: open_bus = 1; break;
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case 0x0200: prg_bank = (prg_bank & 0x1F) | 0x20; break;
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case 0x0300: open_bus = 1; break;
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}
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}
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else if (num_8k_ROM_banks == 192*2)
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{
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// 210-in-1
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switch (addr & 0x0300)
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{
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case 0x0000: break;
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case 0x0100: open_bus = 1; break;
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case 0x0200: prg_bank = (prg_bank & 0x1F) | 0x20; break;
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case 0x0300: prg_bank = (prg_bank & 0x1F) | 0x40; break;
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}
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}
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else if (num_8k_ROM_banks == 256*2)
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{
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// 260-in-1
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}
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if(addr & 0x0800)
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{
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if(addr & 0x1000)
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{
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// upper 16KB Banks
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set_CPU_bank4(prg_bank*4+2);
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set_CPU_bank5(prg_bank*4+3);
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set_CPU_bank6(prg_bank*4+2);
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set_CPU_bank7(prg_bank*4+3);
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}
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else
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{
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// lower 16KB Banks
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set_CPU_bank4(prg_bank*4+0);
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set_CPU_bank5(prg_bank*4+1);
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set_CPU_bank6(prg_bank*4+0);
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set_CPU_bank7(prg_bank*4+1);
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}
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}
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else
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{
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// 32KB Banks
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set_CPU_bank4(prg_bank*4+0);
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set_CPU_bank5(prg_bank*4+1);
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set_CPU_bank6(prg_bank*4+2);
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set_CPU_bank7(prg_bank*4+3);
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}
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if(open_bus)
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{
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NES_6502::Context context;
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parent_NES->cpu->GetContext(&context);
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context.mem_page[4] = dummy;
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context.mem_page[5] = dummy;
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context.mem_page[6] = dummy;
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context.mem_page[7] = dummy;
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parent_NES->cpu->SetContext(&context);
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}
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if(addr & 0x0400)
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{
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set_mirroring(0,0,0,0);
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}
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else if(addr & 0x2000)
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{
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set_mirroring(NES_PPU::MIRROR_HORIZ);
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}
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else
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{
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set_mirroring(NES_PPU::MIRROR_VERT);
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}
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}
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/////////////////////////////////////////////////////////////////////
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