AxibugEmuOnline/OtherCore/MyNes.Standard2/MyNes.Core/Mapper073.cs

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2024-07-24 15:03:33 +08:00
using System.IO;
namespace MyNes.Core
{
[BoardInfo("VRC3", 73)]
internal class Mapper073 : Board
{
private bool irq_mode_8;
private bool irq_enable;
private bool irq_enable_on_ak;
private int irq_reload;
private int irq_counter;
internal override void HardReset()
{
base.HardReset();
Switch16KPRG(PRG_ROM_16KB_Mask, PRGArea.AreaC000);
irq_mode_8 = false;
irq_enable = false;
irq_enable_on_ak = false;
irq_reload = 0;
irq_counter = 0;
}
internal override void WritePRG(ref ushort address, ref byte data)
{
switch (address & 0xF000)
{
case 32768:
irq_reload = (irq_reload & 0xFFF0) | (data & 0xF);
break;
case 36864:
irq_reload = (irq_reload & 0xFF0F) | ((data & 0xF) << 4);
break;
case 40960:
irq_reload = (irq_reload & 0xF0FF) | ((data & 0xF) << 8);
break;
case 45056:
irq_reload = (irq_reload & 0xFFF) | ((data & 0xF) << 12);
break;
case 49152:
irq_mode_8 = (data & 4) == 4;
irq_enable = (data & 2) == 2;
irq_enable_on_ak = (data & 1) == 1;
if (irq_enable)
{
irq_counter = irq_reload;
}
NesEmu.IRQFlags &= -9;
break;
case 53248:
irq_enable = irq_enable_on_ak;
NesEmu.IRQFlags &= -9;
break;
case 61440:
Switch16KPRG(data & 0xF, PRGArea.Area8000);
break;
}
}
internal override void OnCPUClock()
{
if (!irq_enable)
{
return;
}
if (irq_mode_8)
{
irq_counter = (irq_counter & 0xFF00) | (byte)((irq_counter & 0xFF) + 1);
if ((byte)(irq_counter & 0xFF) == byte.MaxValue)
{
NesEmu.IRQFlags |= 8;
irq_counter = (irq_counter & 0xFF00) | (irq_reload & 0xFF);
}
}
else
{
irq_counter++;
if (irq_counter == 65535)
{
NesEmu.IRQFlags |= 8;
irq_counter = irq_reload;
}
}
}
internal override void WriteStateData(ref BinaryWriter stream)
{
base.WriteStateData(ref stream);
stream.Write(irq_mode_8);
stream.Write(irq_enable);
stream.Write(irq_enable_on_ak);
stream.Write(irq_reload);
stream.Write(irq_counter);
}
internal override void ReadStateData(ref BinaryReader stream)
{
base.ReadStateData(ref stream);
irq_mode_8 = stream.ReadBoolean();
irq_enable = stream.ReadBoolean();
irq_enable_on_ak = stream.ReadBoolean();
irq_reload = stream.ReadInt32();
irq_counter = stream.ReadInt32();
}
}
}