/// <summary>
/// Mark memory as allocated and returns its starting address. Changes nothing
/// on the real simulator.
/// Might throw NoFreeMemoryException exception.
/// </summary>
/// <param name="iSize">The size of requested block</param>
public int MemAllocation(int iSize)
{
// Find block with size close to the requested size
int iBlockLocation = FreeMemList.BinarySearch((FreeMemoryInformation)iSize);
if (iBlockLocation < 0)
{
int iIndex = ~iBlockLocation;
// If no block in the request size is free, throw exception
if (iIndex == FreeMemList.Count)
{
throw new NoFreeMemoryException();
}
// Remove the old block from the list
FreeMemoryInformation oldBlock = (FreeMemoryInformation)FreeMemList[iIndex];
FreeMemList.RemoveAt(iIndex);
// add new free block with the size that left
FreeMemList.Add(new FreeMemoryInformation(oldBlock.uiAddress + (uint)iSize,
oldBlock.iSize - iSize));
FreeMemList.Sort();
// return block
return((int)oldBlock.uiAddress);
}
else
{
FreeMemoryInformation oldBlock = (FreeMemoryInformation)FreeMemList[iBlockLocation];
FreeMemList.RemoveAt(iBlockLocation);
return((int)oldBlock.uiAddress);
}
}
/// <summary>
/// Free allocated memory
/// </summary>
/// <param name="iAddress">Address of the block to destroy</param>
public void FreeMemory(uint uiAddress, int iSize)
{
// If the memory is out of the heap area
if (uiAddress < uiHeapBase || uiAddress + iSize > uiHeapBase + iHeapSize)
{
throw new RuntimeError(SimulatorMessage.MEMORY_ACCESS_FAULT, (int)uiAddress);
}
for (int iCounter = 0; iCounter < FreeMemList.Count; ++iCounter)
{
FreeMemoryInformation curBlock = (FreeMemoryInformation)FreeMemList[iCounter];
// if the address is inside a free space
if (uiAddress >= curBlock.uiAddress &&
uiAddress < curBlock.uiAddress + curBlock.iSize)
{
throw new RuntimeError(SimulatorMessage.MEMORY_ACCESS_FAULT, (int)uiAddress);
}
// if the end address is inside a free space
else if (uiAddress + iSize > curBlock.uiAddress &&
uiAddress + iSize < curBlock.uiAddress + curBlock.iSize)
{
throw new RuntimeError(SimulatorMessage.MEMORY_ACCESS_FAULT, (int)uiAddress);
}
// if the block to free includes a free area
else if (uiAddress < curBlock.uiAddress &&
uiAddress + iSize > curBlock.uiAddress + curBlock.iSize)
{
throw new RuntimeError(SimulatorMessage.MEMORY_ACCESS_FAULT, (int)uiAddress);
}
}
FreeMemList.Add(new FreeMemoryInformation(uiAddress, iSize));
FreeMemList.Sort();
}
