vallon@sbmiclr.cs.sunysb.edu (Justin Vallon) (01/23/90)
(Sorry about the double posting... wrong subject first time) In article <44959@improper.coherent.com>, dplatt@coherent.com (Dave Platt) writes: > [Comments about Boomerang] > > Back around 2.0B5 or so, I installed the Mr. Bus Error INIT, which > repeatedly stomps location 0 with an odd doubleword... this rapidly > detects code which is dereferencing an empty-but-not-null handle (very > much a no-no). Boomerang immediately began suffering from bus errors, > aborting the current application. (I assume that Mr. Bus Error is something like a VBL task that writes to location $0 every interrupt). I have two questions. (a) I'm using Virtual. There is no part of the address space (that is, when you've set 14Mb VM space) that will cause a bus error (at least, I believe). The memory map of my Mac II w/14Mb VM: (Addresses are VM addresses, not physical addresses) $000000-$7FFFFF Ram (8 Mb) $800000-$83FFFF Rom (256K) $840000-$EFFFFF Ram (768K + 6 Mb) $F00000-$FFFFFF Video card So, unless the video card causes a bus error (I have no idea about this), then there is no bus-error address. BTW, what's the point of being odd? Isn't a bus error enough? Anyway, 68020's and beyond don't generate address errors, right? (b) Where can I get this. I suppose that it's a few minutes of code, but I'm lazy. > -- > Dave Platt VOICE: (415) 493-8805 > UUCP: ...!{ames,apple,uunet}!coherent!dplatt DOMAIN: dplatt@coherent.com > INTERNET: coherent!dplatt@ames.arpa, ...@uunet.uu.net > USNAIL: Coherent Thought Inc. 3350 West Bayshore #205 Palo Alto CA 94303 -Justin vallon@sbcs.sunysb.edu