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From: rokicki@rocky.STANFORD.EDU (Tomas Rokicki)
Newsgroups: comp.sys.amiga
Subject: Re: Using the blittler directly
Message-ID: <195@rocky.STANFORD.EDU>
Date: Tue, 17-Mar-87 17:47:21 EST
Article-I.D.: rocky.195
Posted: Tue Mar 17 17:47:21 1987
Date-Received: Thu, 19-Mar-87 02:39:43 EST
References: <555@puff.WISC.EDU> <193@rocky.STANFORD.EDU>
Distribution: comp
Organization: Stanford University Computer Science Department
Lines: 32

In article <193@rocky.STANFORD.EDU>, ali@rocky.STANFORD.EDU (Ali Ozer) writes:
> 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.

Actually, the code in blit.c works for the application I needed it
for, but is not as general as it claims to be.  It is most certainly a
starting place, though.  Under 1.1, be careful, since WaitBlit() has
a bug in it where it could return too early . . . 1.2 has this fixed.
Using the blitter isn't that hard . . . maybe I'll update blit.c and
post the final rendition.

> 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).

Cryptic?  It's not that cryptic.  Anymore.  It's a derivative of Logo,
with parameterless subroutines.  Maybe I'll post it this week.  The new
LIFE also supports torus wrap and hi-resolution interlace . . .

> Ali Ozer, ali@rocky.stanford.edu

Tom Rokicki