;;become "A"...."F"
.number
jp txt_output ;display digit
</pre>
The .print_byte_digit routine can be further optimised by devious use of DAA
<pre>
;;-------------------------------------------
;; display number in lower nibble (bits 3..0)
.print_byte_digit
and %00001111 ;isolate lower nibble. (This contains the digit value 0...15)
cp &a ;Less than 10? Set carry if so
sbc a,&69
daa ;Because previous instruction was a subtract operation this
;is known as 'das' in x86
jp txt_output ;display digit
</pre>
[[Category:Programming]]