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From: BLuRry <brendan.rob...@gmail.com>
Newsgroups: comp.sys.apple2.programmer
Subject: Re: FAST 6502 DIVIDE BY 14?
Date: Tue, 14 Aug 2012 13:24:01 -0700 (PDT)
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A table would probably be faster though.  It would take only a few bytes mo=
re to store a table for values 0-20 than it would to write the divide by 7 =
code.  But storing a div7 table would save some room, if you can stand the =
extra opcode for shifting A one place to the right before looking up the ta=
ble.

On Tuesday, August 14, 2012 3:21:56 PM UTC-5, BLuRry wrote:
> Consider divide by 14 as a divide by 2 (easy!) and then by 7.
>=20
>=20
>=20
> Divide by 7:
>=20
> DIVIDE_BY_SEVEN:
>=20
>   LDA BYTE
>=20
>   LSR   =20
>=20
>   LSR   =20
>=20
>   LSR   =20
>=20
>   ADC BYTE
>=20
>   ROR
>=20
>   LSR
>=20
>   LSR
>=20
>   ADC BYTE
>=20
>   ROR=20
>=20
>   LSR
>=20
>   LSR
>=20
>   RTS
>=20
>=20
>=20
> On Tuesday, August 14, 2012 3:09:29 PM UTC-5, (unknown) wrote:
>=20
> > i'VE seen tricks for doing different divides
>=20
> >=20
>=20
> > using 6502...
>=20
> >=20
>=20
> >=20
>=20
> >=20
>=20
> > are there any for divide by 14?
>=20
> >=20
>=20
> >=20
>=20
> >=20
>=20
> > input =3D 1 byte
>=20
> >=20
>=20
> > output =3D byte / 14, remainder=20
>=20
> >=20
>=20
> >=20
>=20
> >=20
>=20
> >=20
>=20
> >=20
>=20
> > Rich