119 lines
3.0 KiB
C#
119 lines
3.0 KiB
C#
using System;
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using System.IO;
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using System.Diagnostics;
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namespace BizHawk.Emulation.Consoles.Nintendo
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{
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//aka MMC6 aka StarTropics and StarTropics 2
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//for simplicity's sake, the behaviour of mmc6 is wrapped up into this board since it isnt used anywhere else
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public class HKROM : MMC3Board_Base
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{
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//configuration
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//state
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bool wram_enabled;
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bool wram_h_enabled, wram_l_enabled;
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bool wram_h_enabled_write, wram_l_enabled_write;
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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 "NES-HKROM":
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AssertPrg(256); AssertChr(256); AssertVram(0); AssertWram(0,1);
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Cart.wram_size = 1; //1K of wram is in the mmc6
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Cart.wram_battery = true; //and its battery backed.
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break;
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case "MAPPER004_MMC6":
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Cart.wram_size = 1; //1K of wram is in the mmc6
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Cart.wram_battery = true; //and its battery backed.
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break;
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default:
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return false;
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}
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BaseSetup();
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mmc3.MMC3Type = MMC3.EMMC3Type.MMC6;
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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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base.SyncState(ser);
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ser.Sync("wram_enabled", ref wram_enabled);
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ser.Sync("wram_h_enabled", ref wram_h_enabled);
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ser.Sync("wram_l_enabled", ref wram_l_enabled);
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ser.Sync("wram_h_enabled_write", ref wram_h_enabled_write);
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ser.Sync("wram_l_enabled_write", ref wram_l_enabled_write);
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}
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public override void WritePRG(int addr, byte value)
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{
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switch (addr & 0x6001)
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{
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case 0x0000: //$8000
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//an extra wram enabled bit is here
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wram_enabled = value.Bit(5);
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if (!wram_enabled)
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{
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wram_h_enabled = wram_l_enabled = false;
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wram_h_enabled_write = wram_l_enabled_write = false;
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}
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break;
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case 0x2001: //$A001
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//a whole host of wram configurations
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if (wram_enabled)
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{
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wram_h_enabled = value.Bit(7);
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wram_l_enabled = value.Bit(5);
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wram_h_enabled_write = value.Bit(6);
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wram_l_enabled_write = value.Bit(4);
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}
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break;
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}
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base.WritePRG(addr, value);
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}
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public override void WriteWRAM(int addr, byte value)
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{
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if (addr < 0x1000)
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return;
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//probably wrong:
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//if (!wram_enabled) return;
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addr &= (1 << 10) - 1;
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int block = addr >> 9;
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bool block_enabled = (block == 1) ? wram_h_enabled : wram_l_enabled;
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bool write_enabled = (block == 1) ? wram_h_enabled_write : wram_l_enabled_write;
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if (write_enabled && block_enabled)
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base.WriteWRAM(addr, value);
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}
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public override byte ReadWRAM(int addr)
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{
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byte open_bus = 0xFF; //open bus
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if (addr < 0x1000)
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return open_bus;
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//probably wrong:
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//if (!wram_enabled) return open_bus;
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addr &= (1 << 10) - 1;
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int block = addr >> 9;
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bool block_enabled = (block == 1) ? wram_h_enabled : wram_l_enabled;
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if (!wram_h_enabled && !wram_l_enabled)
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return open_bus;
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if (block_enabled)
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return base.ReadWRAM(addr);
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else return 0;
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}
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}
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} |