AxibugEmuOnline/OtherCore/MyNes.Standard2/MyNes.Core/Mapper056.cs

98 lines
2.3 KiB
C#

namespace MyNes.Core
{
[BoardInfo("Pirate SMB3", 56)]
internal class Mapper056 : Board
{
private int irqCounter;
private int irqLatch;
private bool irqEnabled;
private int irqControl;
private int switchControl;
internal override string Issues => MNInterfaceLanguage.IssueMapper56;
internal override void HardReset()
{
base.HardReset();
Switch08KPRG(PRG_ROM_08KB_Mask, PRGArea.AreaE000);
irqLatch = 0;
irqCounter = 0;
irqControl = 0;
irqEnabled = false;
}
internal override void WritePRG(ref ushort address, ref byte data)
{
if (address < 61440)
{
switch (address & 0xE000)
{
case 32768:
irqLatch = (irqLatch & 0xFFF0) | (data & 0xF);
break;
case 36864:
irqLatch = (irqLatch & 0xFF0F) | ((data & 0xF) << 4);
break;
case 40960:
irqLatch = (irqLatch & 0xF0FF) | ((data & 0xF) << 8);
break;
case 45056:
irqLatch = (irqLatch & 0xFFF) | ((data & 0xF) << 12);
break;
case 49152:
irqControl = data & 5;
irqEnabled = (data & 2) == 2;
if (irqEnabled)
{
irqCounter = irqLatch;
}
NesEmu.IRQFlags &= -9;
break;
case 53248:
irqEnabled = (irqControl & 1) == 1;
NesEmu.IRQFlags &= -9;
break;
case 57344:
switchControl = data;
break;
}
return;
}
int num = (switchControl & 0xF) - 1;
if (num < 3)
{
Switch08KPRG((data & 0xF) | (PRG_AREA_BLK_INDEX[(num >> 13) + 1] & 0x10), (PRGArea)num);
}
switch (address & 0xC00)
{
case 0:
address &= 3;
if (address < 3)
{
Switch08KPRG((data & 0xF) | (PRG_AREA_BLK_INDEX[(num >> 13) + 1] & 0x10), (PRGArea)address);
}
break;
case 2048:
Switch01KNMTFromMirroring(((data & 1) == 1) ? Mirroring.Vert : Mirroring.Horz);
break;
case 3072:
Switch01KCHR(data, (CHRArea)(address & 7u));
break;
}
}
internal override void OnCPUClock()
{
if (irqEnabled && irqCounter++ == 65535)
{
irqCounter = irqLatch;
NesEmu.IRQFlags |= 8;
}
}
}
}