240.cpp

PocketNester的c++源代码,很好的学习例子,仅供大家学习

/////////////////////////////////////////////////////////////////////
// Mapper 240
void NES_mapper240::Reset()
{
  // set CPU bank pointers
  set_CPU_banks(0,1,num_8k_ROM_banks-2,num_8k_ROM_banks-1);

  // set PPU bank pointers
  if(num_1k_VROM_banks)
  {
    set_PPU_banks(0,1,2,3,4,5,6,7);
  }
}

void NES_mapper240::MemoryWriteLow(uint32 addr, uint8 data)
{
  if(addr >= 0x4100 && addr <= 0x4FFF)
  {
    uint8 prg_bank = data >> 4;
    uint8 chr_bank = data & 0x0F;

    set_CPU_bank4(prg_bank*4+0);
    set_CPU_bank5(prg_bank*4+1);
    set_CPU_bank6(prg_bank*4+2);
    set_CPU_bank7(prg_bank*4+3);

    set_PPU_bank0(chr_bank*8+0);
    set_PPU_bank1(chr_bank*8+1);
    set_PPU_bank2(chr_bank*8+2);
    set_PPU_bank3(chr_bank*8+3);
    set_PPU_bank4(chr_bank*8+4);
    set_PPU_bank5(chr_bank*8+5);
    set_PPU_bank6(chr_bank*8+6);
    set_PPU_bank7(chr_bank*8+7);
  }
}
/////////////////////////////////////////////////////////////////////