Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!spool.mu.edu!news.cs.indiana.edu!news.nd.edu!mentor.cc.purdue.edu!pop.stat.purdue.edu!hrubin From: hrubin@pop.stat.purdue.edu (Herman Rubin) Newsgroups: comp.arch Subject: Re: Segmented Architectures ( formerly Re: 48-bit computers) Message-ID: <9658@mentor.cc.purdue.edu> Date: 5 Apr 91 13:06:48 GMT References: <1991Apr04.023845.3501@kithrup.COM> <4919@lib.tmc.edu> Sender: news@mentor.cc.purdue.edu Lines: 33 In article <4919@lib.tmc.edu>, jmaynard@thesis1.med.uth.tmc.edu (Jay Maynard) writes: > In article <23615@as0c.sei.cmu.edu> firth@sei.cmu.edu (Robert Firth) writes: > >In article <1991Apr04.023845.3501@kithrup.COM> sef@kithrup.COM (Sean Eric Fagan) writes: ..................... > There's nothing that says that array elements in FORTRAN - or, for that > matter, C - have to be contiguous. Thinking that that must be true as a > matter of Natural Law is purest VAXocentrism. > > It's the compiler's job to hide those details from the programmer. It's > a real tragedy that there ate VAXocentric C programmers out there that > think that the whole world should work the way their specific environment > does, and write software with lots of hard-to-find nonportabilities lurking > to trap the unsuspecting soul who tries to run it on non-VAXen. Any machine with a big enough storage of any kind can emulate any other. If it is necessary to do this type of manipulation, a compiler will make a slow mess of it; any decent programmer should be able to use the idiosyncracies of the natural structure of the data to do a better job. It is the hardware designer's job to make it unnecessary to have any more kludges than can be avoided. If the array elements are not contiguous, and there may be very good reasons for the programmer to set things up that way, even the best of the present compilers will cause things to slow down. It is the compiler's job to help the user get the most out of the machine, and hiding things from the user is definitely not the way to do it. -- Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399 Phone: (317)494-6054 hrubin@l.cc.purdue.edu (Internet, bitnet) {purdue,pur-ee}!l.cc!hrubin(UUCP)