Article View: comp.sys.atari.st
Article #26933Re: problems with rnd# from assembler
From: John Stanley
Date: Tue, 19 May 1987 19:51
Date: Tue, 19 May 1987 19:51
29 lines
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1770 bytes
In article <2088@pbhya.UUCP> gdr@pbhya.UUCP (Guy Ridley) writes:
>
>Does anyone have some good documentation on calling trap #17 (the random
>number generator) from assembler? Acc'd to what I have the rnd# generator
>is reseeded when the machine is turned on, and calling trap #17 puts a
>random number in D0. However, what I seem to be getting (based on what
>note comes out of my synthesizer, to which the contents of D0 are sent via
>MIDI) is a lot of decimal "40"'s. This is completely mystifying, and the
>Assempro documentation doesn't say much more that "ST Internals" does.
>Can anyone send me a small sample of such a call that works?
>
No, no, no... It's xbios subfunction 17, NOT trap 17..
(God knows what's on trap 17...)
Try:
move.w #17,-(sp)
trap #14
addq.l #2,sp * random number now in D0
I haven't tried it, but I also haven't heard about anyone else
having problems with it, so it "should" work. (Note: The random
number returned is only 24 bits long so you'll only get from zero
to 16777215 ($00ffffff)...)
---
John Stanley (john@viper.UUCP)
Software Consultant - DynaSoft Systems
UUCP: ...{amdahl,ihnp4,rutgers}!{meccts,dayton}!viper!john
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!rutgers!dayton!viper!john From: john@viper.Lynx.MN.ORG (John Stanley) Newsgroups: comp.sys.atari.st Subject: Re: problems with rnd# from assembler Message-ID: <1021@viper.Lynx.MN.ORG> Date: Tue, 19-May-87 15:51:27 EDT Article-I.D.: viper.1021 Posted: Tue May 19 15:51:27 1987 Date-Received: Sat, 23-May-87 04:13:50 EDT References: <2088@pbhya.UUCP> Reply-To: john@viper.UUCP (John Stanley) Organization: DynaSoft Systems Lines: 29 Keywords: midi/rnd#