116 lines
3.3 KiB
C#
116 lines
3.3 KiB
C#
//////////////////////////////////////////////////////////////////////////
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// Mapper142 SMB2J //
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//////////////////////////////////////////////////////////////////////////
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using System;
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using static VirtualNes.Core.CPU;
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using static VirtualNes.MMU;
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using BYTE = System.Byte;
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using INT = System.Int32;
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namespace VirtualNes.Core
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{
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public class Mapper142 : Mapper
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{
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BYTE prg_sel;
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BYTE irq_enable;
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INT irq_counter;
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public Mapper142(NES parent) : base(parent)
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{
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}
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public override void Reset()
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{
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prg_sel = 0;
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irq_enable = 0;
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irq_counter = 0;
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SetPROM_8K_Bank(3, 0);
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SetPROM_8K_Bank(7, 0x0F);
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if (VROM_1K_SIZE != 0)
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{
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SetVROM_8K_Bank(0);
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}
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}
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//void Mapper142::Write(WORD addr, BYTE data)
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public override void Write(ushort addr, byte data)
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{
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switch (addr & 0xF000)
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{
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case 0x8000:
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irq_counter = (irq_counter & 0xFFF0) | ((data & 0x0F) << 0);
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break;
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case 0x9000:
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irq_counter = (irq_counter & 0xFF0F) | ((data & 0x0F) << 4);
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break;
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case 0xA000:
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irq_counter = (irq_counter & 0xF0FF) | ((data & 0x0F) << 8);
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break;
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case 0xB000:
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irq_counter = (irq_counter & 0x0FFF) | ((data & 0x0F) << 12);
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break;
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case 0xC000:
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irq_enable = (byte)(data & 0x0F);
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nes.cpu.ClrIRQ(IRQ_MAPPER);
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break;
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case 0xE000:
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prg_sel = (byte)(data & 0x0F);
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break;
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case 0xF000:
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switch (prg_sel)
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{
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case 1: SetPROM_8K_Bank(4, data & 0x0F); break;
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case 2: SetPROM_8K_Bank(5, data & 0x0F); break;
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case 3: SetPROM_8K_Bank(6, data & 0x0F); break;
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case 4: SetPROM_8K_Bank(3, data & 0x0F); break;
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}
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break;
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}
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}
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//void Mapper142::HSync(INT scanline)
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public override void HSync(int scanline)
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{
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if (irq_enable != 0)
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{
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if (irq_counter > (0xFFFF - 113))
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{
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irq_counter = 0;
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nes.cpu.SetIRQ(IRQ_MAPPER);
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}
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else
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{
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irq_counter += 113;
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}
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}
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}
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//void Mapper142::SaveState(LPBYTE p)
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public override void SaveState(byte[] p)
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{
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p[0] = prg_sel;
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p[0] = irq_enable;
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//*(INT*)&p[2] = irq_counter;
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BitConverter.GetBytes(irq_counter).CopyTo(p, 2);
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}
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//void Mapper142::LoadState(LPBYTE p)
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public override void LoadState(byte[] p)
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{
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prg_sel = p[0];
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irq_enable = p[1];
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//irq_counter = *(INT*)&p[2];
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irq_counter = BitConverter.ToInt32 (p, 2);
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}
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public override bool IsStateSave()
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{
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return true;
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}
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}
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}
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