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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!news.unimelb.EDU.AU!munnari.OZ.AU!news.mel.connect.com.au!news.mel.aone.net.au!grumpy.fl.net.au!news.webspan.net!newsfeeds.sol.net!news-xfer.netaxs.com!news.mathworks.com!fu-berlin.de!irz401!orion.sax.de!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: What causes a bus error? Date: 19 Jan 1997 22:15:37 GMT Organization: Private BSD site, Dresden Lines: 19 Message-ID: <5bu6e9$fa5@uriah.heep.sax.de> References: <craigs-ya023180001501970036510001@news.os.com> <5biv26$boh@sol.ctr.columbia.edu> <craigs-ya023180001501972048120001@news.os.com> <5brlta$35u@uriah.heep.sax.de> <N.011997.024723.01@scrantr> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.6 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:34276 scrantr@ix.netcom.com (Richard Scranton) wrote: > The understanding I had was that (Sun SPARC, maybe DEC VAX too) > SIGSEGV is caused by an out-of-arena memory access, while a SIGBUS > is caused by a misaligned memory access on an architecture that > traps to the monitor instead of transparently adding wait states > and extra bus cycles. Ah, yes, misaligned access is also a source for SIGBUS. I forgot about this, it's only poorly supported in the x86 arena anyway. 486+ offer misalignment traps, but only for the outermost `ring', i.e. you'll never get it in kernel mode. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)