Int D4 Fn 1A  - Pc-mos/386 V5.01 - Get/set Task Priority                   [O]

   AH = 1Ah
   AL = subfunction (00h read, 01h set, 02h get and set)
   BX = task ID (FFFFh for current task)
   CL = new priority value

Return: CF clear if successful
       CL = current priority value
   CF set on error
       AX = error code (see #1366 at INT 21/AH=59h/BX=0000h)

See Also: AH=1Bh,AH=1Ch