305 lines
8.9 KiB
C#
305 lines
8.9 KiB
C#
using static VirtualNes.MMU;
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using BYTE = System.Byte;
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namespace VirtualNes.Core
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{
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public class Mapper254 : Mapper
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{
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BYTE[] reg = new BYTE[8];
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BYTE prg0, prg1;
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BYTE chr01, chr23, chr4, chr5, chr6, chr7;
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BYTE irq_type;
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BYTE irq_enable;
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BYTE irq_counter;
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BYTE irq_latch;
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BYTE irq_request;
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BYTE protectflag;
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public Mapper254(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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for (int i = 0; i < 8; i++)
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{
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reg[i] = 0x00;
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}
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protectflag = 0;
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prg0 = 0;
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prg1 = 1;
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SetBank_CPU();
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chr01 = 0;
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chr23 = 2;
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chr4 = 4;
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chr5 = 5;
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chr6 = 6;
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chr7 = 7;
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SetBank_PPU();
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irq_enable = 0; // Disable
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irq_counter = 0;
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irq_latch = 0;
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irq_request = 0;
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}
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public override void WriteLow(ushort addr, byte data)
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{
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switch (addr & 0xF000)
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{
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case 0x6000:
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case 0x7000:
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MMU.CPU_MEM_BANK[addr >> 13][addr & 0x1FFF] = data;
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break;
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}
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}
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public override byte ReadLow(ushort addr)
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{
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if (addr >= 0x6000)
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{
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if (protectflag != 0)
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{
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return (MMU.CPU_MEM_BANK[addr >> 13][addr & 0x1FFF]);
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}
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else
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{
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return (byte)((MMU.CPU_MEM_BANK[addr >> 13][addr & 0x1FFF]) ^ 0x1);
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}
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}
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return base.ReadLow(addr);
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}
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public override void Write(ushort addr, byte data)
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{
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switch (addr & 0xE001)
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{
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case 0x8000:
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protectflag = 0xFF;
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reg[0] = data;
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SetBank_CPU();
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SetBank_PPU();
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break;
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case 0x8001:
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reg[1] = data;
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switch (reg[0] & 0x07)
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{
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case 0x00:
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chr01 = (byte)(data & 0xFE);
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SetBank_PPU();
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break;
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case 0x01:
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chr23 = (byte)(data & 0xFE);
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SetBank_PPU();
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break;
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case 0x02:
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chr4 = data;
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SetBank_PPU();
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break;
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case 0x03:
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chr5 = data;
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SetBank_PPU();
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break;
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case 0x04:
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chr6 = data;
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SetBank_PPU();
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break;
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case 0x05:
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chr7 = data;
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SetBank_PPU();
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break;
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case 0x06:
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prg0 = data;
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SetBank_CPU();
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break;
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case 0x07:
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prg1 = data;
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SetBank_CPU();
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break;
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}
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break;
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case 0xA000:
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reg[2] = data;
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if (!nes.rom.Is4SCREEN())
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{
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if ((data & 0x01) != 0) MMU.SetVRAM_Mirror(MMU.VRAM_HMIRROR);
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else MMU.SetVRAM_Mirror(MMU.VRAM_VMIRROR);
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}
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break;
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case 0xA001:
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reg[3] = data;
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break;
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case 0xC000:
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reg[4] = data;
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irq_counter = data;
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irq_request = 0;
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nes.cpu.ClrIRQ(CPU.IRQ_MAPPER);
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break;
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case 0xC001:
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reg[5] = data;
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irq_latch = data;
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irq_request = 0;
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nes.cpu.ClrIRQ(CPU.IRQ_MAPPER);
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break;
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case 0xE000:
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reg[6] = data;
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irq_enable = 0;
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irq_request = 0;
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nes.cpu.ClrIRQ(CPU.IRQ_MAPPER);
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break;
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case 0xE001:
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reg[7] = data;
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irq_enable = 1;
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irq_request = 0;
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nes.cpu.ClrIRQ(CPU.IRQ_MAPPER);
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break;
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}
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}
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public override void Clock(int cycles)
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{
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// if( irq_request && (nes->GetIrqType() == NES::IRQ_CLOCK) ) {
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// nes->cpu->IRQ_NotPending();
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// }
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}
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public override void HSync(int scanline)
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{
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if ((scanline >= 0 && scanline <= 239))
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{
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if (nes.ppu.IsDispON())
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{
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if (irq_enable != 0 && irq_request == 0)
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{
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if (scanline == 0)
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{
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if (irq_counter != 0)
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{
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irq_counter--;
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}
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}
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if ((irq_counter--) == 0)
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{
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irq_request = 0xFF;
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irq_counter = irq_latch;
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nes.cpu.SetIRQ(CPU.IRQ_MAPPER);
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}
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}
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}
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}
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// if( irq_request && (nes->GetIrqType() == NES::IRQ_HSYNC) ) {
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// nes->cpu->IRQ_NotPending();
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// }
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}
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public void SetBank_CPU()
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{
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if ((reg[0] & 0x40) != 0)
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{
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SetPROM_32K_Bank(PROM_8K_SIZE - 2, prg1, prg0, PROM_8K_SIZE - 1);
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}
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else
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{
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SetPROM_32K_Bank(prg0, prg1, PROM_8K_SIZE - 2, PROM_8K_SIZE - 1);
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}
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}
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public void SetBank_PPU()
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{
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if (VROM_1K_SIZE != 0)
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{
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if ((reg[0] & 0x80) != 0)
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{
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SetVROM_8K_Bank(chr4, chr5, chr6, chr7,
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chr01, chr01 + 1, chr23, chr23 + 1);
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}
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else
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{
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SetVROM_8K_Bank(chr01, chr01 + 1, chr23, chr23 + 1,
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chr4, chr5, chr6, chr7);
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}
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}
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else
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{
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if ((reg[0] & 0x80) != 0)
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{
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SetCRAM_1K_Bank(4, (chr01 + 0) & 0x07);
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SetCRAM_1K_Bank(5, (chr01 + 1) & 0x07);
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SetCRAM_1K_Bank(6, (chr23 + 0) & 0x07);
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SetCRAM_1K_Bank(7, (chr23 + 1) & 0x07);
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SetCRAM_1K_Bank(0, chr4 & 0x07);
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SetCRAM_1K_Bank(1, chr5 & 0x07);
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SetCRAM_1K_Bank(2, chr6 & 0x07);
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SetCRAM_1K_Bank(3, chr7 & 0x07);
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}
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else
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{
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SetCRAM_1K_Bank(0, (chr01 + 0) & 0x07);
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SetCRAM_1K_Bank(1, (chr01 + 1) & 0x07);
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SetCRAM_1K_Bank(2, (chr23 + 0) & 0x07);
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SetCRAM_1K_Bank(3, (chr23 + 1) & 0x07);
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SetCRAM_1K_Bank(4, chr4 & 0x07);
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SetCRAM_1K_Bank(5, chr5 & 0x07);
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SetCRAM_1K_Bank(6, chr6 & 0x07);
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SetCRAM_1K_Bank(7, chr7 & 0x07);
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}
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}
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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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public override void SaveState(byte[] p)
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{
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for (int i = 0; i < 8; i++)
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{
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p[i] = reg[i];
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}
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p[8] = prg0;
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p[9] = prg1;
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p[10] = chr01;
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p[11] = chr23;
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p[12] = chr4;
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p[13] = chr5;
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p[14] = chr6;
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p[15] = chr7;
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p[16] = irq_enable;
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p[17] = irq_counter;
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p[18] = irq_latch;
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p[19] = irq_request;
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p[20] = protectflag;
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}
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public override void LoadState(byte[] p)
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{
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for (int i = 0; i < 8; i++)
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{
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reg[i] = p[i];
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}
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prg0 = p[8];
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prg1 = p[9];
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chr01 = p[10];
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chr23 = p[11];
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chr4 = p[12];
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chr5 = p[13];
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chr6 = p[14];
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chr7 = p[15];
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irq_enable = p[16];
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irq_counter = p[17];
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irq_latch = p[18];
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irq_request = p[19];
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protectflag = p[20];
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}
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}
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}
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