Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!decwrl!shelby!polya!rokicki
From: rokicki@polya.Stanford.EDU (Tomas G. Rokicki)
Newsgroups: comp.sys.amiga.tech
Subject: Re: BltBitMap
Message-ID: <11248@polya.Stanford.EDU>
Date: 10 Aug 89 19:10:26 GMT
References: <89222.021843WTW101@PSUVM>
Sender: Tomas G. Rokicki 
Organization: Stanford University
Lines: 24

WTW101@PSUVM.BITNET (Bill Warner) writes:
>    (1) Is the function BltBitMap syncronous or asyncronous?   Does it call
>        WaitBlit?

It's syncronous in that it starts by the time the call returns, but it's
async in that it isn't necessarily finished by that time . . .

>    (2) Assuming the screen I am copying is not static, would it be proper to
>        call Disable() or  Forbid() ?

Not to my knowledge.

>    (3) When the OS is writing to the blitter, does it turn off interrupts?

No, not to my knowledge.

> I am afraid of the following:  I call Disable, then BlitBitMap.  But just
> before I call Disable, some task starts to use the Blitter.  Now when I call
> BlitBitMap it waits for another task to complete its blitter operation (which
> will never happen).

Your fears are grounded.

-tom