Int 31 Fn FF1C  P - Causeway - "lockmem32" - Lock Region Of Memory (32-bi  [E]

   AX = FF1Ch
   ESI = starting linear address
   ECX = size of region in bytes

Return: CF clear if successful
   CF set on error
Desc:  prevent memory from being swapped out by the virtual memory manager

Note:  locks are applied on 4K page boundaries, so memory above and below
     the specified region may be locked as well

See Also: AX=FF1Bh,AX=FF1Eh,AX=FF1Fh