96 lines
1.5 KiB
C++
96 lines
1.5 KiB
C++
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/////////////////////////////////////////////////////////////////////
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// Mapper 43
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void NES_mapper43::Reset()
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{
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set_CPU_banks(2,1,0,4,9);
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set_PPU_banks(0,1,2,3,4,5,6,7);
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//set_mirroring(NES_PPU::MIRROR_VERT);
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irq_enabled = 1;
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irq_counter = 0;
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}
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uint8 NES_mapper43::MemoryReadLow(uint32 addr)
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{
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if(0x5000 <= addr && addr < 0x6000)
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{
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return ROM_banks[0x2000*8 + 0x1000 + (addr - 0x5000)];
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}
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return (uint8)(addr >> 8);
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}
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void NES_mapper43::MemoryWriteLow(uint32 addr, uint8 data)
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{
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if((addr & 0xF0FF) == 0x4022)
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{
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switch(data & 0x07)
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{
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case 0x0:
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case 0x2:
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case 0x3:
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case 0x4:
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{
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set_CPU_bank6(4);
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}
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break;
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case 0x1:
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{
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set_CPU_bank6(3);
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}
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break;
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case 0x5:
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{
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set_CPU_bank6(7);
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}
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break;
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case 0x6:
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{
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set_CPU_bank6(5);
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}
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break;
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case 0x7:
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{
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set_CPU_bank6(6);
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}
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break;
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}
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}
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}
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void NES_mapper43::MemoryWrite(uint32 addr, uint8 data)
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{
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if(addr == 0x8122)
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{
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if(data & 3)
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{
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irq_enabled = 1;
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}
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else
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{
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irq_counter = 0;
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irq_enabled = 0;
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}
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}
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}
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void NES_mapper43::HSync(uint32 scanline)
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{
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if(irq_enabled)
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{
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irq_counter += 114;
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if(irq_counter >= 4096)
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{
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irq_counter -= 4096;
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parent_NES->cpu->DoIRQ();
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}
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}
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}
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/////////////////////////////////////////////////////////////////////
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