Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!nosc!ucsd!ucbvax!CORY.BERKELEY.EDU!dillon
From: dillon@CORY.BERKELEY.EDU (Matt Dillon)
Newsgroups: comp.sys.amiga
Subject: Another 68020 difference
Message-ID: <8806240024.AA11802@cory.Berkeley.EDU>
Date: 24 Jun 88 00:24:50 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 14


	A friend of mine got caught by this one:

	BSET is atomic, right?  OR.w #1,memory?

	wrong

	Guess what?  The 68020 has no compunction for interrupting an
	instruction in the middle of its execution.

	So all those supposedly atomic single-instruction operations people
have probably been doing, and not surrounding them with Forbid()/Permit(),
create windows of vulnerability if you've got a 68020.

							-Matt