Re: A85: a div 6

To: assembly-85@lists.ticalc.org
Subject: Re: A85: a div 6
From: EeulPlek <axeeodyx@easley.net>
Date: Mon, 30 Nov 1998 11:07:24 -0500
Delivered-To: assembly-85-outgoing@towerguard.unix.edu.sollentuna.se
Organization: Digital Insanity International
References: <3.0.6.32.19981128224040.00844270@mail.cybrzn.com>
Reply-To: assembly-85@lists.ticalc.org



> can anyone give me some z80 asm for getting the integer division of
> a deivided by 6???
> quick, hackiest thing you can think of.
> im stumped.  there should be a way to do this, but i cant find it. 
> the only way i can think of would be to take a-6 and inc until a-6<0,
> then dont inc and you are done.  this would suck bad, but i may have
> to use it.

There is a routine in the calculator's ROM which does integer division
rather quickly.  I'm not sure if it's a good thing to use if you have
an 8-bit divisor, but in general it looks very efficient to me.  To use
it, you call UNPACK_HL+2 with HL being the dividend and C holding the
divisor.  It returns the quotient in HL and the remainder in A.  It
works with any unsigned integers.  To divide A by 6:

	ld	l,a
	ld	h,0
	ld	c,6
	call	UNPACK_HL+2
	ld	a,l		;If you really need result in A

References:

A85: a div 6

From: Kaus <kaus@cybrzn.com>