Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!rutgers!cbmvax!carolyn
From: carolyn@cbmvax.commodore.com (Carolyn Scheppner - CATS)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Assembly Graphics Help Needed
Message-ID: <22748@cbmvax.commodore.com>
Date: 27 Jun 91 19:47:44 GMT
References: <91177.015130G60LG@CUNYVM.BITNET>
Reply-To: carolyn@cbmvax.commodore.com (Carolyn Scheppner - CATS)
Organization: Commodore, West Chester, PA
Lines: 24

In article <91177.015130G60LG@CUNYVM.BITNET> G60LG@CUNYVM.BITNET (Anton Mitchell) writes:
>
>     I have tried to get this assembly program to work for the longest.
>Any help would be great. What I dont understand is when assembled and
>executed the bitplanes are not cleared. When allocating the memory I set
>the Clear and Chip flags. But it is not cleared. The only way I have been
>able to clear the bitplanes is by using:
>                                         lea     PlaneAdr,a1
>                                         move.l  PlaneSize*6,d1
>                                 Loop:   move.w  #0,(a1)+
>                                         dbra    d1,Loop

I don't know if anyone has pointed this out yet, but do you know
that the decrement-and-branch instructions (like dbra) operate on
just the low word of the data register ? ie. the maximum number
of iterations a single dbra loop can get you is 65536.  So you
are probably only moving a portion of what you are trying to move...
-- 
==========================================================================
 Carolyn Scheppner -- Tech. Mgr. CATS - Commodore Amiga Technical Support
 PHONE 215-431-9180 {uunet,rutgers}!cbmvax!carolyn  carolyn@commodore.com

 Signed characters are xenophobic.  
==========================================================================