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Interesting, makes pretty much no difference to just calculate 16 bit values, rather than relying on byte layout.

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2019-02-18 22:28:20 +00:00
parent 9ac2c53685
commit 23489b7127
1 changed files with 19 additions and 15 deletions
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34
EightBit/Register16.cs
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@ -6,30 +6,21 @@ namespace EightBit
{
using System.Runtime.InteropServices;
// This'll only work for little endian host processors...
[StructLayout(LayoutKind.Explicit)]
public struct Register16
{
[FieldOffset(0)]
public byte Low;
[FieldOffset(1)]
public byte High;
[FieldOffset(0)]
public ushort Word;
public Register16(byte low, byte high)
{
this.Word = 0;
this.Low = low;
this.High = high;
}
public Register16(ushort value)
{
this.Low = this.High = 0;
this.Word = value;
this.Low = Chip.LowByte(value);
this.High = Chip.HighByte(value);
}
public Register16(int value)
@ -44,9 +35,22 @@ namespace EightBit
public Register16(Register16 rhs)
{
this.Low = 0;
this.High = 0;
this.Word = rhs.Word;
this.Low = rhs.Low;
this.High = rhs.High;
}
public ushort Word
{
get
{
return (ushort)(this.Low | Chip.PromoteByte(this.High));
}
set
{
this.Low = Chip.LowByte(value);
this.High = Chip.HighByte(value);
}
}
public static Register16 operator ++(Register16 value) => Increment(value);
@ -77,7 +81,7 @@ namespace EightBit
}
var rhs = (Register16)obj;
return rhs.Word == this.Word;
return rhs.Low == this.Low && rhs.High == this.High;
}
public override int GetHashCode() => this.Word;