Path: utzoo!attcan!uunet!mcsun!sunic!kth!draken!d88-jwa
From: d88-jwa@nada.kth.se (Reply via mail or intl. +46 8 258 268...)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Integer Size problem
Message-ID: <1478@draken.nada.kth.se>
Date: 24 Aug 89 11:59:07 GMT
References: <15141@dartvax.Dartmouth.EDU> <11689@cit-vax.Caltech.Edu> <1465@draken.nada.kth.se> <13727@polyslo.CalPoly.EDU>
Reply-To: d88-jwa@nada.kth.se (Jon W{tte)
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 25

In article <13727@polyslo.CalPoly.EDU> dorourke@polyslo.CalPoly.EDU (David M. O'Rourke) writes:
>d88-jwa@nada.kth.se (Jon W{tte) writes:
>>Wrong. Incorrect. What happens if a interrupt happens between the set
>>pointers and the block move instruction ? And this interrupt happens
>>to shuffle memory ? LOCK THE HANDLES first ! ALWAYS !
>
>  As I understand it, interrupt routines can't do any memory allocation
>stuff during the service of the interrupt.  I always felt that this was one
>of the funner aspects of the Mac's OS.  Am I wrong???

That's right, USER interrupt routines can't shuffle memory. But try tracing
a _HLock or something like it in MacsBug. You'll see that all Handle handling
is part of DoVBLTask (At least on my SEx and MacsBug 6.0, might be that the
procedure names are wrong for thia ROM ?)

What is a VBL task ? I think it's an interrupt (at least, used to be on the
plusses :-)

I think that interrupts in the OS shuffle data, but ours may not. Damned
segregation ! ,-)

Happy hacking
-- 
This is your fortune from h+@nada.kth.se:
Anarchy is better that no government at all.