95 lines
2.0 KiB
C#
95 lines
2.0 KiB
C#
using System.IO;
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namespace MyNes.Core
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{
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[BoardInfo("Mario Baby", 42)]
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internal class Mapper042 : Board
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{
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private int SRAM_PRG_Page;
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private bool irqEnable;
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private int irqCounter;
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internal override void HardReset()
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{
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base.HardReset();
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Switch32KPRG(PRG_ROM_32KB_Mask, PRGArea.Area8000);
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}
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internal override void WritePRG(ref ushort address, ref byte data)
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{
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if (address == 32768)
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{
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Switch08KCHR(data);
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return;
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}
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if (address == 61440)
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{
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SRAM_PRG_Page = data << 13;
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return;
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}
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switch (address & 0xE003)
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{
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case 57344:
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Switch08KPRG(data, PRGArea.Area6000);
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break;
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case 57345:
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if ((data & 8) == 8)
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{
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Switch01KNMTFromMirroring(Mirroring.Horz);
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}
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else
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{
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Switch01KNMTFromMirroring(Mirroring.Vert);
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}
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break;
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case 57346:
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irqEnable = (data & 2) == 2;
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if (!irqEnable)
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{
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irqCounter = 0;
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}
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NesEmu.IRQFlags &= -9;
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break;
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}
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}
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internal override void OnCPUClock()
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{
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if (!irqEnable)
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{
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return;
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}
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int num = irqCounter++;
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if ((irqCounter & 0x6000) != (num & 0x6000))
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{
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if ((irqCounter & 0x6000) == 24576)
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{
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NesEmu.IRQFlags |= 8;
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}
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else
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{
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NesEmu.IRQFlags &= -9;
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}
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}
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}
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internal override void WriteStateData(ref BinaryWriter stream)
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{
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base.WriteStateData(ref stream);
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stream.Write(SRAM_PRG_Page);
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stream.Write(irqEnable);
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stream.Write(irqCounter);
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}
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internal override void ReadStateData(ref BinaryReader stream)
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{
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base.ReadStateData(ref stream);
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SRAM_PRG_Page = stream.ReadInt32();
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irqEnable = stream.ReadBoolean();
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irqCounter = stream.ReadInt32();
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}
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}
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}
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