/// <summary>
/// Attempts to create a new EMS handle.
/// </summary>
/// <param name="pagesRequested">Number of pages to allocate to the new handle.</param>
/// <returns>New EMS handle if created successfully; otherwise null.</returns>
private int CreateHandle(int pagesRequested)
{
for (int i = FirstHandle; i <= LastHandle; i++)
{
if (!handles.ContainsKey(i))
{
EmsHandle handle = new EmsHandle(pagesRequested);
handles.Add(i, handle);
return(i);
}
}
return(0);
}
public static byte EmsToConv(EmsHandle sourceHandle, int sourcePage, int sourcePageOffset, PhysicalMemory memory, uint destAddress, int length)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException(nameof(length));
}
if (length == 0)
{
return(0);
}
if (destAddress + length > PhysicalMemory.ConvMemorySize)
{
return(0xA2);
}
if (sourcePageOffset >= ExpandedMemoryManager.PageSize)
{
return(0x95);
}
int offset = sourcePageOffset;
uint sourceCount = destAddress;
int pageIndex = sourcePage;
while (length > 0)
{
int size = Math.Min(length, ExpandedMemoryManager.PageSize - offset);
byte[] source = sourceHandle.GetLogicalPage(pageIndex);
if (source == null)
{
return(0x8A);
}
for (int i = 0; i < size; i++)
{
memory.SetByte(sourceCount++, source[offset + i]);
}
length -= size;
pageIndex++;
offset = 0;
}
return(0);
}
public static byte EmsToEms(EmsHandle srcHandle, int sourcePage, int sourcePageOffset, EmsHandle destHandle, int destPage, int destPageOffset, int length)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException(nameof(length));
}
if (length == 0)
{
return(0);
}
if (sourcePageOffset >= ExpandedMemoryManager.PageSize || destPageOffset >= ExpandedMemoryManager.PageSize)
{
return(0x95);
}
bool overlap = false;
bool reverse = false;
if (srcHandle == destHandle)
{
int sourceStart = sourcePage * ExpandedMemoryManager.PageSize + sourcePageOffset;
int destStart = destPage * ExpandedMemoryManager.PageSize + destPageOffset;
int sourceEnd = sourceStart + length;
int destEnd = destStart + length;
if (sourceStart < destStart)
{
overlap = sourceEnd > destStart;
}
else
{
overlap = destEnd > sourceStart;
reverse = overlap;
}
}
if (!reverse)
{
int sourceOffset = sourcePageOffset;
int currentSourcePage = sourcePage;
int destOffset = destPageOffset;
int currentDestPage = destPage;
while (length > 0)
{
int size = Math.Min(Math.Min(length, ExpandedMemoryManager.PageSize - sourceOffset), ExpandedMemoryManager.PageSize - destOffset);
byte[] source = srcHandle.GetLogicalPage(currentSourcePage);
byte[] dest = destHandle.GetLogicalPage(currentDestPage);
if (source == null || dest == null)
{
return(0x8A);
}
for (int i = 0; i < size; i++)
{
dest[destOffset + i] = source[sourceOffset + i];
}
length -= size;
sourceOffset += size;
destOffset += size;
if (sourceOffset == ExpandedMemoryManager.PageSize)
{
sourceOffset = 0;
currentSourcePage++;
}
if (destOffset == ExpandedMemoryManager.PageSize)
{
destOffset = 0;
currentDestPage++;
}
}
}
else
{
throw new NotImplementedException();
}
return(overlap ? (byte)0x92 : (byte)0);
}