116 lines
2.3 KiB
C#
116 lines
2.3 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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namespace BizHawk.Emulation.Consoles.Nintendo
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{
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class Mapper50 : NES.NESBoardBase
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{
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//http://wiki.nesdev.com/w/index.php/INES_Mapper_050
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byte prg_bank;
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int prg_bank_mask_8k;
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bool irq_enable;
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ushort irq_counter = 0;
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bool irq_ready = false;
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int ppu_cyclecount = 0;
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public override bool Configure(NES.EDetectionOrigin origin)
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{
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//analyze board type
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switch (Cart.board_type)
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{
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case "MAPPER050":
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break;
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default:
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return false;
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}
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prg_bank = 0;
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prg_bank_mask_8k = Cart.prg_size / 8 - 1;
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SetMirrorType(EMirrorType.Vertical);
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return true;
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}
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public override void SyncState(Serializer ser)
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{
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ser.Sync("ppu_cyclecount", ref ppu_cyclecount);
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ser.Sync("prg_bank", ref prg_bank);
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ser.Sync("irq_enable", ref irq_enable);
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ser.Sync("irq_counter", ref irq_counter);
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ser.Sync("irq_ready", ref irq_ready);
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base.SyncState(ser);
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}
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public override void WriteEXP(int addr, byte value)
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{
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addr &= 0x0120;
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if (addr == 0x0020)
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{
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prg_bank = (byte)(((value & 1) << 2) | ((value & 2) >> 1) | ((value & 4) >> 1) | (value & 8));
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}
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else if (addr == 0x0120)
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{
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irq_enable = value.Bit(0);
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if (!irq_enable)
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{
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SyncIRQ(irq_enable);
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irq_counter = 0;
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}
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}
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}
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public override byte ReadPRG(int addr)
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{
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if (addr < 0x2000)
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{
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return ROM[(0x08 * 0x2000) + (addr & 0x1FFF)];
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}
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else if (addr < 0x4000)
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{
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return ROM[(0x09 * 0x2000) + (addr & 0x1FFF)];
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}
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else if (addr < 0x6000)
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{
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int bank = (prg_bank & prg_bank_mask_8k);
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return ROM[(bank * 0x2000) + (addr & 0x1FFF)];
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}
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else
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{
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return ROM[(0x0B * 0x2000) + (addr & 0x1FFF)];
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}
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}
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public override byte ReadWRAM(int addr)
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{
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return ROM[(0x0F * 0x2000) + (addr & 0x1FFF)];
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}
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private void IRQ_Ready()
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{
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base.SyncIRQ(irq_ready);
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}
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public override void ClockCPU()
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{
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if (irq_enable)
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{
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irq_counter += 1;
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if (irq_counter == 0x1000)
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SyncIRQ(true);
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}
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}
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/*
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public override void ClockPPU()
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{
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ppu_cyclecount++;
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if (ppu_cyclecount >= 3)
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{
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ppu_cyclecount = 0;
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IRQ_Tick();
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base.ClockPPU();
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}
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}*/
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}
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}
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