160 lines
3.4 KiB
C#
160 lines
3.4 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 Mapper230 : NES.NESBoardBase
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{
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/*
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* Here are Disch's original notes:
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========================
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= Mapper 230 =
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========================
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Example Game:
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--------------------------
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22-in-1
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Reset Driven:
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---------------------------
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The mapper has 2 main modes: Contra mode, and multicart mode. Performing a Soft Reset switches between
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them.
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Notes:
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---------------------------
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This multicart has an odd PRG size (not power of 2). This is because there are 2 PRG chips.
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The first is 128k and contains Contra, the other is 512k and contains the multicart.
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A soft reset changes which chip is used as well as other stuff relating to the mode
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Registers:
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---------------------------
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Contra Mode $8000-FFFF: [.... .PPP]
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Multicart Mode $8000-FFFF: [.MOP PPPP]
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M = Mirroring (0=Horz, 1=Vert)
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O = PRG Mode
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P = PRG Page
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Note:
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Mirroring is always Vert in Contra Mode.
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PRG Setup:
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---------------------------
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$8000 $A000 $C000 $E000
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+---------------+---------------+
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Contra Mode: | $8000 | { 7 } | <--- use chip 0
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+-------------------------------+
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Multi Mode 0: | <Reg> | <--- use chip 1
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+-------------------------------+
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Multi Mode 1: | Reg | Reg | <--- use chip 1
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+---------------+---------------+
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chip 0 = 128k PRG (offset 0x00010-0x2000F)
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chip 1 = 512k PRG (offset 0x20010-0xA000F)
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*/
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//TODO: soft reset back to contra = fails
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public int prg_page;
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public bool prg_mode;
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public bool contra_mode;
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public int chip0_prg_bank_mask_16k = 0x07;
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public int chip1_prg_bank_mask_16k = 0x1F;
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public int chip1_offset = 0x20000;
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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 "MAPPER230":
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break;
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default:
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return false;
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}
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contra_mode = true;
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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("contra_mode", ref contra_mode);
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ser.Sync("prg_page", ref prg_page);
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ser.Sync("prg_mode", ref prg_mode);
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base.SyncState(ser);
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}
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public override void WritePRG(int addr, byte value)
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{
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if (contra_mode)
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{
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prg_page = value & 0x07;
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}
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else
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{
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prg_page = value & 0x1F;
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prg_mode = value.Bit(5);
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if (value.Bit(6))
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{
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SetMirrorType(EMirrorType.Vertical);
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}
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else
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{
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SetMirrorType(EMirrorType.Horizontal);
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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 (contra_mode)
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{
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if (addr < 0x4000)
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{
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return ROM[((prg_page & chip0_prg_bank_mask_16k) * 0x4000) + addr];
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}
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else
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{
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return ROM[(7 * 0x4000) + (addr & 0x3FFF)];
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}
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}
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else
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{
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if (prg_mode == false)
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{
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return ROM[((prg_page >> 1) * 0x8000) + addr + chip1_offset];
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}
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else
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{
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int page = prg_page + 8;
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return ROM[(page * 0x4000) + (addr & 0x03FFF)];
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}
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}
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}
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public override void NESSoftReset()
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{
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contra_mode ^= true;
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prg_page = 0;
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prg_mode = false;
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SetMirrorType(EMirrorType.Vertical);
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}
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}
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}
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