168 lines
3.4 KiB
C#
168 lines
3.4 KiB
C#
using BizHawk.Common;
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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public sealed class Mapper243 : NES.NESBoardBase
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{
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// http://wiki.nesdev.com/w/index.php/INES_Mapper_243
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int reg_addr;
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bool var_a;
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ByteBuffer regs = new ByteBuffer(8);
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int chr_bank_mask_8k, prg_bank_mask_32k;
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public override bool Configure(NES.EDetectionOrigin origin)
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{
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switch (Cart.board_type)
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{
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case "MAPPER243":
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break;
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case "UNIF_UNL-Sachen-74LS374N":
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var_a = true;
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break;
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default:
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return false;
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}
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chr_bank_mask_8k = Cart.chr_size / 8 - 1;
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prg_bank_mask_32k = Cart.prg_size / 32 - 1;
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return true;
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}
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public override void Dispose()
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{
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regs.Dispose();
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base.Dispose();
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}
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public override void SyncState(Serializer ser)
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{
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ser.Sync("reg_addr", ref reg_addr);
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ser.Sync("regs", ref regs);
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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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switch (addr & 0x01)
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{
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case 0x0000:
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reg_addr = value & 0x07;
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break;
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case 0x0001:
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if (var_a)
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{
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switch (reg_addr)
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{
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case 0:
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// set prg bank to 0
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regs[5] = 0;
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// set chr bank to 3
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regs[2] = 0;
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regs[4] = 3;
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regs[6] = 0;
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break;
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case 2:
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regs[2] = (byte)(value & 0x01);
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break;
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case 4:
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regs[4] = (byte)(value & 0x01);
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break;
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case 5:
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regs[5] = (byte)(value & 0x07);
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break;
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case 6:
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regs[6] = (byte)(value & 0x03);
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break;
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case 7:
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int mirror = value & 1;
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switch (mirror)
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{
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case 0:
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SetMirrorType(EMirrorType.Horizontal);
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break;
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case 1:
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SetMirrorType(EMirrorType.Vertical);
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break;
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}
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break;
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}
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break;
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}
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else
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{
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switch (reg_addr)
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{
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case 2:
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regs[2] = (byte)(value & 0x01);
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regs[5] = (byte)(value & 0x01);
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break;
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case 4:
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regs[4] = (byte)(value & 0x01);
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break;
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case 5:
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regs[5] = (byte)(value & 0x07);
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break;
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case 6:
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regs[6] = (byte)(value & 0x03);
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break;
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case 7:
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int mirror = (value >> 1) & 0x03;
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switch (mirror)
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{
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case 0:
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SetMirrorType(EMirrorType.Horizontal);
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break;
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case 1:
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SetMirrorType(EMirrorType.Vertical);
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break;
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case 2:
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SetMirroring(0, 1, 1, 1);
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break;
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case 3:
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SetMirrorType(EMirrorType.OneScreenA);
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break;
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}
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break;
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}
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break;
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}
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}
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}
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public override byte ReadPPU(int addr)
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{
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if (var_a)
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{
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if (addr < 0x2000)
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{
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int chr_bank = regs[4] | (regs[6] << 1) | (regs[2] << 3);
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return VROM[((chr_bank & chr_bank_mask_8k) * 0x2000) + addr];
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}
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else
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{
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return base.ReadPPU(addr);
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}
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}
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else
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{
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if (addr < 0x2000)
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{
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int chr_bank = (regs[4] << 2) | (regs[6]) | (regs[2] << 3);
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return VROM[((chr_bank & chr_bank_mask_8k) * 0x2000) + addr];
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}
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else
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{
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return base.ReadPPU(addr);
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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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return ROM[((regs[5] & prg_bank_mask_32k) * 0x8000) + addr];
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}
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}
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}
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