Article View: comp.sys.amiga.tech
Article #7458Re: Lattice BLink problem
From: Randell Jesup
Date: Wed, 12 Dec 1990 23:32
Date: Wed, 12 Dec 1990 23:32
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1564 bytes
In article <1990Nov26.181340.17891@cck.cov.ac.uk> csg019@cck.cov.ac.uk (Z*A*P*H*O*D) writes:
>I don't realy know much about C but you could link a module with the following
>assembly language program, this will return a psedo random number (it is in
>fact the current raster beam Y-position...
>you could use it if you are realy desperate...
>
>start
> move.b $dff006,random
> rts
Unfortunately, that produces an extremely poor random number. First,
it's limited to 0-255, secondly certain values will never show up (due to
vblank interrupts, TOF stuff, etc eating all the cpu for those lines),
thirdly, the distribution of the numbers remaining will be uneven due to
PAL machines having more than 256 lines, and NTSC having less.
Just Say No.
--
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com BIX: rjesup
Thus spake the Master Ninjei: "If your application does not run correctly,
do not blame the operating system." (From "The Zen of Programming") ;-)
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arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!rutgers!bagate!cbmvax!jesupReferences:
<1990Nov22.133240.12613@gdr.bath.ac.uk> <1990Nov26.181340.17891@cck.cov.ac.uk>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!rutgers!bagate!cbmvax!jesup From: jesup@cbmvax.commodore.com (Randell Jesup) Newsgroups: comp.sys.amiga.tech Subject: Re: Lattice BLink problem Message-ID: <16490@cbmvax.commodore.com> Date: 12 Dec 90 23:32:56 GMT References: <1990Nov22.133240.12613@gdr.bath.ac.uk> <1990Nov26.181340.17891@cck.cov.ac.uk> Reply-To: jesup@cbmvax.commodore.com (Randell Jesup) Organization: Commodore, West Chester, PA Lines: 23