72 lines
1.6 KiB
C#
72 lines
1.6 KiB
C#
using System.IO;
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namespace MyNes.Core
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{
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[BoardInfo("FDS-Port - Alt. Levels", 50)]
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internal class Mapper050 : Board
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{
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private int prg_page;
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private int irq_counter;
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private bool irq_enabled;
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internal override void HardReset()
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{
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base.HardReset();
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Switch08KPRG(15, PRGArea.Area6000);
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Switch08KPRG(8, PRGArea.Area8000);
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Switch08KPRG(9, PRGArea.AreaA000);
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Switch08KPRG(11, PRGArea.AreaE000);
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}
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internal override void WriteEX(ref ushort address, ref byte data)
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{
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switch (address & 0x4120)
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{
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case 16416:
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prg_page = (data & 8) | ((data & 1) << 2) | ((data >> 1) & 3);
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Switch08KPRG(prg_page, PRGArea.AreaC000);
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break;
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case 16672:
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irq_enabled = (data & 1) == 1;
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if (!irq_enabled)
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{
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irq_counter = 0;
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NesEmu.IRQFlags &= -9;
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}
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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 (irq_enabled)
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{
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irq_counter++;
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if (irq_counter == 4096)
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{
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NesEmu.IRQFlags |= 8;
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irq_counter = 0;
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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(prg_page);
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stream.Write(irq_counter);
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stream.Write(irq_enabled);
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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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prg_page = stream.ReadInt32();
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irq_counter = stream.ReadInt32();
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irq_enabled = stream.ReadBoolean();
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}
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}
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}
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