public static uint MemAlloc(uint aLength)
{
if (aLength == 0)
{
DebugAndHalt(" Request to retrieve block with size = 0 was halted!");
}
var xInterruptsWereEnabled = CPU.DisableInterrupts();
try
{
EnsureIsInitialized();
var xCurrentTableIdx = mLastTableIndex;
DataLookupTable *xCurrentTable = GlobalSystemInfo.GlobalInformationTable->FirstDataLookupTable;
DataLookupTable *xPreviousTable = null;
uint xResult;
while (xCurrentTable != null)
{
DebugHex("Scanning DataLookupTable ", xCurrentTableIdx);
//DebugHex("At address", (uint)xCurrentTable);
if (ScanDataLookupTable(xCurrentTableIdx, xCurrentTable, aLength, out xResult))
{
DebugHex("Returning handle", xResult);
DebugHex("For dataobject size", aLength);
if (xResult < CPU.GetEndOfKernel())
{
DebugAndHalt("Wrong handle returned!");
}
return(xResult);
}
xCurrentTableIdx++;
xPreviousTable = xCurrentTable;
xCurrentTable = xCurrentTable->Next;
mLastTableIndex = xCurrentTableIdx;
mLastEntryIndex = 0;
}
// no tables found, lets create a new one, and use that
if (xPreviousTable == null)
{
// this check should theoretically be unnecessary, but lets keep it, to do some double-checking.
DebugAndHalt("No PreviousTable found!");
}
Debug("Creating new DataLookupTable");
var xLastItem = xPreviousTable->GetEntry(DataLookupTable.EntriesPerTable - 1);
var xNextTablePointer = (DataLookupTable *)((uint)xLastItem->DataBlock + xLastItem->Size);
// the memory hasn't been cleared yet, so lets do that now.
ClearMemory(xNextTablePointer, GlobalSystemInfo.TotalDataLookupTableSize);
xPreviousTable->Next = xNextTablePointer;
xNextTablePointer->Previous = xPreviousTable;
if (!ScanDataLookupTable(xCurrentTableIdx, xNextTablePointer, aLength, out xResult))
{
// Something seriously weird happened: we could create a new DataLookupTable (with new entries)
// but couldn't allocate a new handle from it.
DebugAndHalt(" Something seriously weird happened: we could create a new DataLookupTable (with new entries), but couldn't allocate a new handle from it.");
}
DebugHex("Returning handle", xResult);
DebugHex("For dataobject size", aLength);
mLastTableIndex = xCurrentTableIdx;
mLastEntryIndex = 0;
return(xResult);
}
finally
{
if (xInterruptsWereEnabled)
{
CPU.EnableInterrupts();
}
else
{
//Debug(" Not enabling interrupts, because they weren't enabled yet!");
}
}
}
