Selector and Allocation classes

SelectorsAndAllocations.cs

// Allocation represents the actual memory behind one or more selectors
public class Allocation
{
    public Allocation(uint bytes, ushort flags)
    {
        this.flags = flags;
        buffer = new byte[bytes];
    }
    public ushort flags;            // GlobalAlloc flags
    public byte[] buffer;           // The actual "memory"!
    public LocalHeap localHeap;     // Only if this allocation has a local heap
}

// This selector class is very similar to a selector descriptor table
// in a real processor.  It maps a 16-bit selector to an actual allocation.
public class Selector
{
    public ushort selectorIndex;    // Base selector index allocated from RangeAllocator
    public Allocation allocation;   // The memory behind this selector
    public bool isCode;             // Can code be executed via this selector?
    public bool readOnly;           // Read-only or read/write?

    // Generate the 16-bit selector used from 16-bit code.
    public ushort selector
    {
        get
        {
            // Upper 13-bits ar the selector index, lower three bits are ring level
            // and descriptor table flag.  These lower three bit values seem to match
            // what Windows does but aren't really important
            return (ushort)((selectorIndex << 3) | (isCode ? 0x02 : 0x03));
        }
    }
}