INT 15 - TopView - "GETMEM" - ALLOCATE "SYSTEM" MEMORY
        AX = 1001h
        BX = number of bytes to allocate
Return: ES:DI -> block of memory or 0000h:0000h (DV v2.26+)
Note:   use SETERROR (AX=DE15h) to avoid a user prompt if there is insufficient
          common memory
SeeAlso: AX=DE0Ch,AX=DE15h