Do you have something like this in mind (don't know any Z80 DAA tricks
;-):

  ;; w contains binary nybble (0..15)
  addlw 256-10          ; set C if w is 0A..0F -> w is 0..5 for 0A..0F
  btfss STATUS,C
  addlw '0' + 10 - 'A'
  addlw 'A'             ;; w contains ASCII digit

The first addlw could be modified to trip the DAA mechanism on a Z80 or
other processor (the DC would happen when you need it).

Peter

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics