Decimal up counter

Decimal up counter
 org 00h
clr a
up:inc a
 da a
 acall delay
 sjmp up
delay: mov r0,#0ffh
     h2:mov r1,#020h
h1:mov r2,#0ffh
 h:djnz r2,h
  djnz r1,h1
  djnz r0,h2
  ret
  end