mirror of
https://github.com/libretro/Mesen.git
synced 2024-11-23 17:19:39 +00:00
122 lines
2.7 KiB
C++
122 lines
2.7 KiB
C++
#pragma once
|
|
#include "BaseMapper.h"
|
|
#include "CPU.h"
|
|
|
|
class FrontFareast : public BaseMapper
|
|
{
|
|
private:
|
|
uint16_t _irqCounter;
|
|
bool _irqEnabled;
|
|
bool _ffeAltMode;
|
|
|
|
protected:
|
|
uint16_t GetPRGPageSize() { return 0x2000; }
|
|
uint16_t GetCHRPageSize() { return 0x400; }
|
|
uint32_t GetChrRamSize() { return 0x8000; }
|
|
uint16_t RegisterStartAddress() { return 0x42FE; }
|
|
uint16_t RegisterEndAddress() { return 0x4517; }
|
|
|
|
void InitMapper()
|
|
{
|
|
_irqCounter = 0;
|
|
_irqEnabled = false;
|
|
_ffeAltMode = true;
|
|
|
|
switch(_mapperID) {
|
|
case 6:
|
|
AddRegisterRange(0x8000, 0xFFFF, MemoryOperation::Write);
|
|
SelectPrgPage2x(0, 0);
|
|
SelectPrgPage2x(1, 14);
|
|
break;
|
|
|
|
case 8:
|
|
AddRegisterRange(0x8000, 0xFFFF, MemoryOperation::Write);
|
|
SelectPrgPage4x(0, 0);
|
|
break;
|
|
|
|
case 17:
|
|
SelectPrgPage4x(0, -4);
|
|
break;
|
|
}
|
|
}
|
|
|
|
void StreamState(bool saving)
|
|
{
|
|
BaseMapper::StreamState(saving);
|
|
Stream(_irqCounter, _irqEnabled, _ffeAltMode);
|
|
}
|
|
|
|
void ProcessCpuClock()
|
|
{
|
|
if(_irqEnabled) {
|
|
_irqCounter++;
|
|
if(_irqCounter == 0) {
|
|
CPU::SetIRQSource(IRQSource::External);
|
|
_irqEnabled = false;
|
|
}
|
|
}
|
|
}
|
|
|
|
void WriteRegister(uint16_t addr, uint8_t value)
|
|
{
|
|
switch(addr) {
|
|
case 0x42FE:
|
|
_ffeAltMode = (value & 0x80) == 0x00;
|
|
switch((value >> 4) & 0x01) {
|
|
case 0: SetMirroringType(MirroringType::ScreenAOnly); break;
|
|
case 1: SetMirroringType(MirroringType::ScreenBOnly); break;
|
|
}
|
|
break;
|
|
|
|
case 0x42FF:
|
|
switch((value >> 4) & 0x01) {
|
|
case 0: SetMirroringType(MirroringType::Vertical); break;
|
|
case 1: SetMirroringType(MirroringType::Horizontal); break;
|
|
}
|
|
break;
|
|
|
|
case 0x4501:
|
|
_irqEnabled = false;
|
|
CPU::ClearIRQSource(IRQSource::External);
|
|
break;
|
|
|
|
case 0x4502:
|
|
_irqCounter = (_irqCounter & 0xFF00) | value;
|
|
CPU::ClearIRQSource(IRQSource::External);
|
|
break;
|
|
|
|
case 0x4503:
|
|
_irqCounter = (_irqCounter & 0x00FF) | (value << 8);
|
|
_irqEnabled = true;
|
|
CPU::ClearIRQSource(IRQSource::External);
|
|
break;
|
|
|
|
default:
|
|
if(_mapperID == 6) {
|
|
if(addr >= 0x8000) {
|
|
if(HasChrRam() || _ffeAltMode) {
|
|
SelectPrgPage2x(0, (value & 0xFC) >> 1);
|
|
value &= 0x03;
|
|
}
|
|
SelectChrPage8x(0, value << 3);
|
|
}
|
|
} else if(_mapperID == 8) {
|
|
if(addr >= 0x8000) {
|
|
SelectPrgPage2x(0, (value & 0xF8) >> 2);
|
|
SelectChrPage8x(0, (value & 0x07) << 3);
|
|
}
|
|
} else {
|
|
switch(addr) {
|
|
case 0x4504: case 0x4505: case 0x4506: case 0x4507:
|
|
SelectPRGPage(addr - 0x4504, value);
|
|
break;
|
|
|
|
case 0x4510: case 0x4511: case 0x4512: case 0x4513: case 0x4514: case 0x4515: case 0x4516: case 0x4517:
|
|
SelectCHRPage(addr - 0x4510, value);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
};
|