90 lines
2.3 KiB
C#
90 lines
2.3 KiB
C#
namespace EMU7800.Core
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{
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/// <summary>
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/// Tigervision 8KB bankswitched carts
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/// </summary>
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public sealed class CartTV8K : Cart
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{
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//
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// Cart Format Mapping to ROM Address Space
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// Segment1: 0x0000:0x0800 0x1000:0x0800 Selected segment via $003F
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// Segment2: 0x0800:0x0800 0x1800:0x0800 Always last segment
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// Segment3: 0x1000:0x0800
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// Segment4: 0x1800:0x0800
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//
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ushort BankBaseAddr;
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readonly ushort LastBankBaseAddr;
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byte Bank
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{
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set
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{
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BankBaseAddr = (ushort)(0x0800 * value);
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BankBaseAddr %= (ushort)ROM.Length;
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}
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}
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protected internal override bool RequestSnooping
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{
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get { return true; }
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}
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#region IDevice Members
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public override void Reset()
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{
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Bank = 0;
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}
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public override byte this[ushort addr]
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{
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get
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{
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addr &= 0x0fff;
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return addr < 0x0800 ? ROM[BankBaseAddr + (addr & 0x07ff)] : ROM[LastBankBaseAddr + (addr & 0x07ff)];
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}
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set
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{
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if (addr <= 0x003f)
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{
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Bank = value;
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}
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}
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}
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#endregion
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private CartTV8K()
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{
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}
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public CartTV8K(byte[] romBytes)
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{
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LoadRom(romBytes, 0x1000);
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Bank = 0;
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LastBankBaseAddr = (ushort)(ROM.Length - 0x0800);
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}
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#region Serialization Members
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public CartTV8K(DeserializationContext input, MachineBase m) : base(input)
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{
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input.CheckVersion(1);
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LoadRom(input.ReadExpectedBytes(0x1000), 0x1000);
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BankBaseAddr = input.ReadUInt16();
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LastBankBaseAddr = input.ReadUInt16();
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}
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public override void GetObjectData(SerializationContext output)
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{
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base.GetObjectData(output);
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output.WriteVersion(1);
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output.Write(ROM);
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output.Write(BankBaseAddr);
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output.Write(LastBankBaseAddr);
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}
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#endregion
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}
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} |