Path: 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

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")  ;-)