Int 21 Fn 2519  P - Phar Lap 386/dos-extender Vmm - Get Additional Memory  [E]

   AX = 2519h

Return: CF clear
   EAX = error code
       0000h  no error
       0001h  out of physical memory
       0002h  out of swap space (unable to grow swap file)
       0003h  out of LDT entries and unable to grow LDT
       0004h  unable to change extended memory allocation mark
       FFFFFFFFh   paging disabled

Note:  VMM is the Virtual Memory Manager option