Int D4 Fn 13  - PC-mos/386 V5.01 - Get Alias For Selector (native Mode On  [O]

   AH = 13h
   AL = type of alias selector (00h data, 01h stack, 02h code)
   BX = selector

Return: CF clear if successful
       AX = new selector or 0000h if BX selector not found
   CF set on error
       AX = error code (see INT 21/AH=59h)

See Also: AH=11h,AH=12h