var   MBI: MEMORY_BASIC_INFORMATION;
VirtualQuery(pointer($400000),MBI,$1000);
if (MBI.State and MEM_FREE) =	MEM_FREE then
if (MBI.RegionSize -(dword(MBI.AllocationBase)-$400000)) >= $6000  then
  VirtualAlloc(pointer($00400000),$6000,MEM_COMMIT, PAGE_EXECUTE_READWRITE)
  else xyz;