ShowHex:	
	push af
		and %11110000
			rrca
			rrca
			rrca
			rrca
		call PrintHexChar
	pop af
	and %00001111
	;call PrintHexChar  (execution flows into it naturally)
PrintHexChar:
	or a	   ;Clear Carry Flag
	daa
	add a,&F0
	adc a,&40     ;this sequence of instructions converts a single hex digit to ASCII.

	jp PrintChar  ;this is whatever routine prints to the screen on your system.
                      ;  It must end in a "ret" and it must take the accumulator as its argument.