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From: ali@rocky.STANFORD.EDU (Ali Ozer)
Newsgroups: comp.sys.amiga
Subject: Re: Using the blittler directly
Message-ID: <193@rocky.STANFORD.EDU>
Date: Tue, 17-Mar-87 14:50:48 EST
Article-I.D.: rocky.193
Posted: Tue Mar 17 14:50:48 1987
Date-Received: Thu, 19-Mar-87 01:32:55 EST
References: <555@puff.WISC.EDU>
Reply-To: ali@rocky.UUCP (Ali Ozer)
Distribution: comp
Organization: Stanford University Computer Science Department
Lines: 23

[]

Using the blitter directly (from C or assembly) is certainly possible.
You should take a look at "blit.c" that appeared with Tom Rokicki's
life source code in Fish disk 31. The code is nice and short, and shows you
how to load the blitter registers and then start it up. Of course, you 
fist have to Own the blitter, and, before doing any subsequent blitter
operations, you have to wait for the previous blitter operation to
conclude... I don't remember the exact function names to do this
stuff; take a look at the code. Also, there is a certain order in which
you load the registers; loading one of the registers starts the
blitter, so that one should be done last. And finally, I don't think
you need to turn of interrupts or anything --- Just make sure the
blitter is yours before you load the registers.

Of course, I've heard people complain that the code in "blit.c" 
works only for Tom and no one else... 

BTW, Tom has a brand new version of Life --- No, it doesn't go any faster
but it does let you specify, through a most cryptic programming language,
the initial startup picture... He should post it SOON (hint hint, Tom).

Ali Ozer, ali@rocky.stanford.edu