Re: A86: long division

To: assembly-86@lists.ticalc.org
Subject: Re: A86: long division
From: Dux Gregis <assets@eden.rutgers.edu>
Date: Tue, 04 Aug 1998 00:15:49 -0600
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
References: <3.0.5.32.19980803011533.00875100@tfs.net>
Reply-To: assembly-86@lists.ticalc.org


This won't work if hl is less than 7.  Once the loop is executed 256 times, the
carry flag sets and sends the subtraction amiss.


David Phillips wrote:

> You could run a loop, subtracting hl from your number once each time, and
> keep track of how many times you subtracted it, until the remaining number
> is smaller than hl.  That number would be the remainder, and the number of
> times you subtracted would be the quotient.
>
>
> ; NOT tested!
> ; in: de = dividend, hl = divisor
> ; out: a = quotient, hl = remainder - dividend (add dividend to get remainder)
> de_div_hl:
>  ex de,hl
>  xor a
> loop:
>  sbc hl,de
>  ret c
>  inc a
>  jr loop   ; or use jp, to add 1 byte/save 2 t-states
>
>
> At 02:03 AM 8/3/98 EDT, you wrote:
> >
> >Lets say that I only need to save the integer part of the quotient...would
> >that change anything?
> >
>
> --
> David Phillips
> mailto:electrum@tfs.net
> ICQ: 13811951
> AOL/AIM: electrum32

References:

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