From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: Ada95 to ANSI_C converter
Date: 1997/04/03
Date: 1997-04-03T00:00:00+00:00 [thread overview]
Message-ID: <dewar.860115225@merv> (raw)
In-Reply-To: E831sB.M4s@world.std.com
Bob said
<<Anyway, I think Robert is correct in that machine code (for most
machines) can catch overflows efficiently, whereas ANSI C cannot.
Particular implementations of C might be able to. So there's something
"fundamental" about this inefficiency, if we're talking about standard,
portable C.
>>
The implementation tricks that Bob refers to can alleviate some of the
cost of overflow checking, but by no means all, on any architecture
that I can imagine. One can always of course build a C compiler that
specifically recognizes "overflow patterns", and reliably generate
optimal code with the check -- I know of no such C compiler.
I will make the statement once more, unconditionally and clearly: The
decision to generate C, rather than object code directly, involves
a number of fundamental inefficiencies, one of which is overflow checking!
I have not seen anything that contests this position!
next prev parent reply other threads:[~1997-04-03 0:00 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5hbrah$ctt$1@gail.ripco.com>
1997-03-26 0:00 ` Ada95 to ANSI_C converter Nick Roberts
1997-03-26 0:00 ` Robert Dewar
1997-03-27 0:00 ` Jennifer E. Lee
1997-03-28 0:00 ` Craig Franck
1997-03-28 0:00 ` Robert Dewar
1997-03-28 0:00 ` Steve Doiel
1997-03-28 0:00 ` Robert Dewar
1997-04-02 0:00 ` Richard Kenner
1997-04-02 0:00 ` Robert Dewar
1997-04-02 0:00 ` Richard Kenner
1997-04-02 0:00 ` Robert Dewar
1997-04-02 0:00 ` Robert A Duff
1997-04-04 0:00 ` Keith Thompson
1997-04-04 0:00 ` Robert Dewar
1997-04-07 0:00 ` Arthur Schwarz
1997-04-07 0:00 ` Peter Seebach
1997-04-07 0:00 ` Kaz Kylheku
1997-04-07 0:00 ` Robert Dewar
1997-04-08 0:00 ` Robert A Duff
1997-04-08 0:00 ` Keith Thompson
1997-04-02 0:00 ` Richard Kenner
1997-04-03 0:00 ` Fergus Henderson
1997-03-27 0:00 ` Craig Franck
1997-03-27 0:00 ` Jennifer E. Lee
1997-03-27 0:00 ` Jennifer E. Lee
1997-03-27 0:00 ` Philip Johnson
1997-04-01 0:00 ` Jennifer E. Lee
1997-04-02 0:00 ` Philip E. Johnson
1997-04-03 0:00 ` Jon S Anthony
1997-03-28 0:00 ` Robert Dewar
1997-03-28 0:00 ` Craig Franck
1997-03-28 0:00 ` Robert Dewar
1997-04-01 0:00 ` David Kristola
1997-04-01 0:00 ` Jennifer E. Lee
1997-04-01 0:00 ` Tom Wheeley
1997-04-01 0:00 ` Robert I. Eachus
1997-03-27 0:00 ` Jeff Carter
1997-03-28 0:00 ` Jon S Anthony
1997-03-28 0:00 ` Jon S Anthony
1997-03-28 0:00 ` Robert Dewar
1997-04-02 0:00 ` Jon S Anthony
1997-04-03 0:00 ` Robert Dewar
1997-04-04 0:00 ` Jon S Anthony
1997-04-03 0:00 ` Jon S Anthony
1997-04-03 0:00 ` Robert A Duff
1997-04-03 0:00 ` Robert Dewar [this message]
1997-04-03 0:00 ` Robert Dewar
1997-04-04 0:00 ` Jon S Anthony
1997-04-04 0:00 ` Robert Dewar
1997-04-04 0:00 ` Robert Dewar
1997-04-07 0:00 ` Jon S Anthony
1997-04-07 0:00 ` Jon S Anthony
1997-03-31 0:00 ` Jon S Anthony
1997-03-31 0:00 ` Robert Dewar
1997-04-01 0:00 ` Robert A Duff
1997-03-31 0:00 ` David Emery
1997-04-03 0:00 ` Jon S Anthony
1997-04-03 0:00 ` Jennifer E. Lee
1997-04-04 0:00 ` Howard W. LUDWIG
1997-04-16 0:00 Dan Lehman
1997-04-17 0:00 ` Robert Dewar
1997-04-20 0:00 ` Nick Roberts
1997-04-20 0:00 ` Robert Dewar
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