60 lines
1.3 KiB
C++
60 lines
1.3 KiB
C++
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//////////////////////////////////////////////////////////////////////////
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// Mapper073 Konami VRC3 //
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//////////////////////////////////////////////////////////////////////////
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void Mapper073::Reset()
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{
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irq_enable = 0;
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irq_counter = 0;
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SetPROM_32K_Bank( 0, 1, PROM_8K_SIZE-2, PROM_8K_SIZE-1 );
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}
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void Mapper073::Write( WORD addr, BYTE data )
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{
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switch( addr ) {
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case 0xF000:
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SetPROM_16K_Bank( 4, data );
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break;
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case 0x8000:
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irq_counter = (irq_counter & 0xFFF0) | (data & 0x0F);
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break;
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case 0x9000:
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irq_counter = (irq_counter & 0xFF0F) | ((data & 0x0F) << 4);
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break;
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case 0xA000:
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irq_counter = (irq_counter & 0xF0FF) | ((data & 0x0F) << 8);
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break;
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case 0xB000:
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irq_counter = (irq_counter & 0x0FFF) | ((data & 0x0F) << 12);
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break;
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case 0xC000:
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irq_enable = data;
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break;
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}
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}
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void Mapper073::Clock( INT cycles )
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{
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if( irq_enable & 0x02 ) {
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if( (irq_counter+=cycles) >= 0xFFFF ) {
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irq_enable = 0;
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irq_counter &= 0xFFFF;
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// nes->cpu->IRQ_NotPending();
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nes->cpu->SetIRQ( IRQ_TRIGGER );
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}
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}
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}
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void Mapper073::SaveState( LPBYTE p )
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{
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p[0] = irq_enable;
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*(INT*)&p[1] = irq_counter;
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}
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void Mapper073::LoadState( LPBYTE p )
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{
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irq_enable = p[0];
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irq_counter = *(INT*)&p[1];
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}
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