Path: utzoo!utgpu!watserv1!watmath!att!pacbell!osc!jgk From: jgk@osc.COM (Joe Keane) Newsgroups: comp.arch Subject: Re: Killer Micro II Summary: Machines support what languages ask for. Keywords: floating point, language Message-ID: <3785@osc.COM> Date: 11 Sep 90 01:30:12 GMT References: <527@llnl.LLNL.GOV> <603@array.UUCP> <2482@l.cc.purdue.edu> <2497@l.cc.purdue.edu> <3755@osc.COM> <2493@crdos1.crd.ge.COM> Reply-To: jgk@osc.COM (Joe Keane) Organization: Versant Object Technology, Menlo Park, CA Lines: 34 In article <3755@osc.COM> i write: >Our current programming languages have a strong influence. C has `float' and >`double' types, and most machines have single-precision and double-precision >floating point numbers. Coincidence? I think not. In article <2493@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.com (bill davidsen) writes: > I miss this. Single and double precision came around before C by about >a decade. Yes they went into C when it was designed. If you are implying >that C was the reason manufacturers have double in hardware, the >timeline runs the wrong way. In article <3945@bingvaxu.cc.binghamton.edu> vu0310@bingvaxu.cc.binghamton.edu (R. Kym Horsell) writes: >Eh? This is putting the cart before the horse somewhat... Fortran >predates C by a good interval and they only put DP into *Fortran* >because the h/w supported it (and they didn't want assembly-level >guys being able to get hold of it & not Fortran guys). Sorry, i'm not too clear when i'm being sarcastic. I didn't mean to imply that C was the source of machines having two floating-point formats, only that they have common roots. I guess that would be whatever machine Fortran was first implemented on. Suppose Fortran started out with three floating-point formats, and furthermore suppose that C also had this. Then i bet you'd see a lot of machines today which directly support three different floating-point formats. Of course you can always make two of them the same, but most machines probably wouldn't. Another example is that Common Lisp has multi-precision integers and short floating-point types. If you look at a Lisp machine, you'll find that these types are supported directly by the microcode. There's nothing mysterious about this; it's quite natural. Of course people don't build Lisp machines any more, but that's another story...