Path: utzoo!attcan!uunet!lll-winken!ames!oliveb!amiga!boing!dale
From: dale@boing.UUCP (Dale Luck)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Unsupported Programming Practices
Message-ID: <589@boing.UUCP>
Date: 9 Jan 89 23:02:20 GMT
References: <8901060406.AA22607@postgres.Berkeley.EDU> <84277@sun.uucp> <43@sdcc10.ucsd.EDU>
Reply-To: dale@boing.UUCP (Dale Luck)
Organization: Boing, Milpitas, Ca.
Lines: 35

In article  (John Schultz) writes:
>
>  Just do a WaitBlit().  OwnBlitter probably calls WaitBlit(),

Nope, it does nothing with WaitBlit

>then you'll also have to call DisownBlitter() before you call any
>rom routines.

True, but only if those routines will use the blitter.
In general it is a bad idea to be owning the blitter while doing
unrelated things.

>  For custom blitter stuff, I've always done:
>    WaitBlit();
>    OwnBlitter();
>     // do custom blits
>    DisownBlitter();

Nope, this may typically work but wont work under stress. Some other
task can get in between the WaitBlit and OwnBlitter resulting in
a busy Blitter.
After OwnBlitter you need to do a WaitBlit before accessing the
custom chip registers.
All OwnBlitter does is guarentee that no one else will use the blitter
once OwnBlitter returns and before you call DisownBlitter. It has
nothing to do with the current operation status of the blitter.

>
>  John Schultz


-- 
Dale Luck     GfxBase/Boing, Inc.
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