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. RokickiOrganization: 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