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From: dcw@lcs.mit.edu (David C. Whitney)
Newsgroups: comp.sys.apple2
Subject: Re: random no. in assembly?
Message-ID: <1991Jan30.125552.5794@mintaka.lcs.mit.edu>
Date: 30 Jan 91 12:55:52 GMT
References: <9101300829.AA21626@apple.com>
Sender: daemon@mintaka.lcs.mit.edu (Lucifer Maleficius)
Organization: MIT Spoken Language Systems Group
Lines: 18

In article <9101300829.AA21626@apple.com> C489030@UMCVMB.MISSOURI.EDU (Greg Hodgdon) writes:
>Hi all.  I am looking for a way to generate random numbers in an assembly
>language program.  The entry point to the applesoft RND function would
>be a start, but I really just need an algorithm.  I'm using one that
>shifts a 2-byte seed left once and adds it back to the seed. that doesn't
>give very good results after the first few numbers.

I wrote a simple one that basically does a CRC-16 (I can send you a
6502 CRC-16 calculator) on values grabbed from somewhere on page $C0
(something like $C022 or something). These softswitches usually have
random changing garbage in them, so they supply numbers about as
random as you can get.

--
Dave Whitney
Computer Science MIT 1990	| I wrote Z-Link and BinSCII. Send me bug
dcw@lcs.mit.edu   dcw@mit.edu	| reports. I have a job. Don't send me offers.
"The price of freedom is eternal vigilance" --Binky (aka Matt Groening)