Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!gatech!udel!nigel.ee.udel.edu!mccalpin From: mccalpin@perelandra.cms.udel.edu (John D. McCalpin) Newsgroups: comp.arch Subject: Re: IEEE arithmetic (Goldberg paper) Message-ID: Date: 29 Jun 91 13:34:09 GMT References: <9106282329.AA20495@ucbvax.Berkeley.EDU> Sender: usenet@ee.udel.edu Organization: College of Marine Studies, U. Del. Lines: 33 Nntp-Posting-Host: perelandra.cms.udel.edu In-reply-to: jbs@WATSON.IBM.COM's message of 28 Jun 91 23:13:12 GMT >>>>> On 28 Jun 91 23:13:12 GMT, jbs@WATSON.IBM.COM said: jbs> The DO, ENDDO construct is not in the Fortran 77 standard. jbs> Nevertheless many Fortran 77 compilers recognize it and many users use jbs> it. I would not advise omitting it from your compiler in order to jbs> "expose" "broken" user code. The word "broken" is clearly being used in this context to refer to code whose behavior is undetermined under the standard --- therefore *logically* "broken". The examples which have been the topic of discussion here depend on either subtle issues of floating-point code re-arrangement or (in the other thread) on a particular implementation's treatment of functions with side effects. The use of extensions is an entirely different issue. The resulting codes are *syntactically* incorrect FORTRAN-77 --- their *logical* interpretation under a *superset* of the FORTRAN language is independent of the fact that extensions are used. I certainly appreciate any efforts that a compiler makes to tell me my code is either broken or non-portable. Most major vendors provide compiler switches to flag ANSI non-compliance. Very few provide robust and comprehensive extensions to detect common *logical* errors, such as: -- use of uninitialized variables -- argument mismatch in calling sequences -- use of undeclared variables (mispellings) -- out-of-bounds array references in called routines (often a result of an argument mismatch) -- John D. McCalpin mccalpin@perelandra.cms.udel.edu Assistant Professor mccalpin@brahms.udel.edu College of Marine Studies, U. Del. J.MCCALPIN/OMNET