Article View: comp.arch
Article #20657Re: RT/PC Unaligned Accesses
From: Robert Firth
Date: Wed, 05 Apr 1989 13:04
Date: Wed, 05 Apr 1989 13:04
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In article <4646@pt.cs.cmu.edu> bsy@PLAY.MACH.CS.CMU.EDU (Flexi-thumbs) writes: >I'm not arguing that the RT is a great machine... but you might as well say >use your reductio argument for the BSD Vax implementation -- NULL pointers >are too often dereferenced: correct programs still run correctly; only >programs that dereference NULL gets into trouble (when ported to a Sun, for >example), and those are broken anyway.... In my opinion, the argument is still valid. Dereferencing a null pointer should cause a trap; if an implementation silently does the wrong thing it is seriously stupid. When I first started porting to Vax/VMS I found one or two null-pointer dereferences in almost every major systems program. Every case was an accident waiting to happen. An editor had three examples, one of which would certainly have cost the hapless user her entire edit session. It is so easy to map out page zero of the virtual address space. Why be so stupid for so little gain?
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!rochester!pt.cs.cmu.edu!sei!firth From: firth@sei.cmu.edu (Robert Firth) Newsgroups: comp.arch Subject: Re: RT/PC Unaligned Accesses Message-ID: <3142@bd.sei.cmu.edu> Date: 5 Apr 89 13:04:06 GMT References: <4618@pt.cs.cmu.edu> <oYBLMhy00jaRA1ZlFZ@andrew.cmu.edu> <4628@pt.cs.cmu.edu> <28664@ucbvax.BERKELEY.EDU> <4646@pt.cs.cmu.edu> Reply-To: firth@sei.cmu.edu (Robert Firth) Organization: Software Engineering Institute, Pittsburgh, PA Lines: 19