Connecting the CPU to the Global Heap

GlobalHeapIBus.cs

// Read a byte from the global heap
public byte ReadByte(ushort seg, ushort offset)
{
    // Crack the selector
    var sel = GetSelector(seg);

    try
    {
        // Read it
        return sel.allocation.buffer[((seg >> 3) - sel.selectorIndex) << 16 | offset];
    }
    catch (NullReferenceException)
    {
        throw new Sharp86.SegmentNotPresentException();
    }
    catch (IndexOutOfRangeException)
    {
        throw new Sharp86.GeneralProtectionFaultException();
    }
}

// Write a byte to the global heap
public void WriteByte(ushort seg, ushort offset, byte value)
{
    // Crack the selector
    var sel = GetSelector(seg);
    
    // Don't allow writes to read-only/code selectors
    if (sel.readOnly || sel.isCode)
        throw new Sharp86.GeneralProtectionFaultException();

    try
    {
        // Write it
        sel.allocation.buffer[((seg >> 3) - sel.selectorIndex) << 16 | offset] = value;
    }
    catch (NullReferenceException)
    {
        throw new Sharp86.SegmentNotPresentException();
    }
    catch (IndexOutOfRangeException)
    {
        throw new Sharp86.GeneralProtectionFaultException();
    }
}