Any more graceful way to saturate adds?

I am working in 16-bit 808x assembler (yes, on an old 808x CPU) and
adding two 8-bit numbers to each other and saturating the result.
Here is the best I could come up with:

; AL and DL have unsigned 8-bit values to add
; DL is actually extended into DX (ie. 00xxh)
   cbw            ; Make AL a signed word
   add   dx,ax    ; Do word sized add, into DX
   jns   @[EMAIL PROTECTED]
   ; jump if result not signed/negative
   xor   dx,dx    ; Underflowed; make 0
@[EMAIL PROTECTED]
   or   dh,dh     ; Did it overflow?
   jz   @[EMAIL PROTECTED]
      ; if not, we're ok
   mov   dx,00FFh ; Overflowed; force our saturation value (FFh)
@[EMAIL PROTECTED]
 is part of an ADPCM inner loop.

Is this about as fast as I can expect?  Or am I missing an obvious
technique?  (I am not an 808x assembler expert)