public void Map(IMemorySegment segment, ushort startAddress, bool overwriteMappedPages = false)
{
int size = (int)segment.SizeInBytes;
if (startAddress % PAGE_SIZE_IN_BYTES > 0)
{
throw new MemoryMapException($"Start address must be on a page boundary (divisible by {PAGE_SIZE_IN_BYTES}).");
}
if (startAddress + size > SizeInBytes)
{
throw new MemoryMapException($"Block would overflow the memory space which is {SizeInBytes} bytes.");
}
int startPage = PageFromAddress(startAddress);
int endPage = startPage + (size / PAGE_SIZE_IN_BYTES) - 1;
if (!overwriteMappedPages && _pageMap[startPage..endPage].Any(p => p != null))
{
throw new MemoryMapException("Would overwrite existing mapped page/s. Specify overwriteMappedPages = true to enable masking the existing memory.");
}
if (!_segments.Contains(segment))
{
_segments.Add(segment);
segment.MapAt(startAddress);
}
else
{
throw new MemoryMapException("This segment has already been mapped into memory and cannot be mapped twice.");
}
for (int i = startPage; i <= endPage; i++)
{
_pageMap[i] = segment; // map a reference to this segment into every 1K page it runs over, so we can quickly fetch the segment for any address
}
}