Groups > comp.lang.java.programmer > #6521

Re: Arithmetic overflow checking

From	David Thompson <dave.thompson2@verizon.net>
Newsgroups	comp.lang.java.programmer, comp.lang.c
Subject	Re: Arithmetic overflow checking
Date	2011-07-24 22:13 -0400
Organization	Poor
Message-ID	<32kp27hs1qqcvmdcs9ol4cqg9ge7e4q2u7@4ax.com> (permalink)
References	(4 earlier) <3797038f-22d1-40b2-8c12-60db5a0976b8@t5g2000yqj.googlegroups.com> <fn3m17p1p5ipsit6ltmg6rqtlcf5kvdmep@4ax.com> <1d742049-31f6-4eb6-8832-9cce3f25091d@a31g2000vbt.googlegroups.com> <ivg9cp$akq$1@dont-email.me> <08jn17t10eb6qgfdlvriqq8j6e17k5u2ou@4ax.com>

Cross-posted to 2 groups.

Show all headers | View raw

On Mon, 11 Jul 2011 21:31:11 -0700, Gene Wirchenko <genew@ocis.net>
wrote:

> On Mon, 11 Jul 2011 21:51:28 -0400, Eric Sosman
> <esosman@ieee-dot-org.invalid> wrote:
> 
> >On 7/11/2011 5:54 PM, tm wrote:
> >>[...]
> >> Correct results can be computed without any slowdown,
> >> when the CPU is able to trigger an overflow interupt.
> >>
> >> A slowdown would only happen when an overflow occurs.
> >> Computations without overflow would run at full speed.
> >
> >     Well, no.  At least, not in any trap-capable architecture I've
> >seen.  Three points:
> 
> [snipped nice explanation]
> 
>      How about an example of such an architecture?  A URL would be
> fine.  I believe that /370 had something like that for floating point,
> but not for integer.
> 
S/360 and all successors have masked interrupts for overflows in
'fixed-point' (integer) and decimal (BCD), and unmasked for (original)
floating-point now retronymed 'hex' floating-point. Since IIRC S/390
there is also 'binary' (IEEE) floating-point with its own separate and
more complicated status flags, masks and interrupt causes.

I can't find a usable ref on the IBM site, but if you trust bitsavers:
http://bitsavers.org/pdf/ibm/360/princOps/A22-6821-0_360PrincOps.pdf
page 16 figs 14 and 16, and pp 25 and 33, 35 and 39, 42 and 49.

A few high(er)-performance models of 360, and IIRC 370, did make FP
traps 'imprecise' = not synchronous with the 'right' instruction.

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-10 01:47 -0700
  Re: Arithmetic overflow checking China Blue Dolls <chine.bleu@yahoo.com> - 2011-07-10 02:47 -0700
    Re: Arithmetic overflow checking pete <pfiland@mindspring.com> - 2011-07-10 06:04 -0400
      Re: Arithmetic overflow checking China Blue Dolls <chine.bleu@yahoo.com> - 2011-07-10 03:29 -0700
        Re: Arithmetic overflow checking Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-07-10 20:52 +0300
        Re: Arithmetic overflow checking pete <pfiland@mindspring.com> - 2011-07-10 23:29 -0400
    Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-10 04:44 -0700
      Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-12 11:33 +0100
        Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 04:17 -0700
          Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-12 12:33 +0100
            Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 05:24 -0700
              Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-12 21:45 -0400
          Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-12 05:25 -0700
            Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 10:21 -0700
              Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 23:54 -0700
            Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-12 19:14 +0100
              Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-13 00:20 -0700
        Re: Arithmetic overflow checking markspace <-@.> - 2011-07-12 09:26 -0700
          Re: Arithmetic overflow checking Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-07-12 10:52 -0600
            Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-12 10:48 -0700
          Re: Arithmetic overflow checking Martin Gregorie <martin@address-in-sig.invalid> - 2011-07-12 16:54 +0000
            Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 11:35 -0700
          Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 10:13 -0700
          Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-12 21:53 -0400
        Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-14 23:41 -0500
          Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-15 10:56 -0700
            Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-15 21:27 -0500
      Re: Arithmetic overflow checking bugbear <bugbear@trim_papermule.co.uk_trim> - 2011-07-20 09:22 +0100
        Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-20 10:51 -0700
          Re: Arithmetic overflow checking gordonb.3urm7@burditt.org (Gordon Burditt) - 2011-07-20 15:39 -0500
          Re: Arithmetic overflow checking "BartC" <bc@freeuk.com> - 2011-07-21 12:12 +0100
    Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-10 09:28 -0400
      Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-10 06:52 -0700
        Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-10 14:47 -0700
      Re: Arithmetic overflow checking "MikeP" <mp011011@some.org> - 2011-07-14 23:07 -0500
    Re: Arithmetic overflow checking Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-07-10 12:25 -0400
  Re: Arithmetic overflow checking Robert Wessel <robertwessel2@yahoo.com> - 2011-07-10 10:47 -0500
  Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 07:58 -0700
    Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-11 10:48 -0700
      Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 14:40 -0700
    Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-11 14:54 -0700
      Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 15:55 -0700
      Re: Arithmetic overflow checking Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-07-11 21:51 -0400
        Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-11 21:31 -0700
          Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-11 23:16 -0700
          Re: Arithmetic overflow checking James Kuyper <jameskuyper@verizon.net> - 2011-07-12 06:28 -0400
          Re: Arithmetic overflow checking David Thompson <dave.thompson2@verizon.net> - 2011-07-24 22:13 -0400
            Re: Arithmetic overflow checking Lew Pitcher <lpitcher@teksavvy.com> - 2011-07-25 10:24 -0400
  Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-12 09:05 +0200
    Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 02:22 -0700
      Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-12 11:34 +0200
        Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-12 03:04 -0700
        Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-12 03:33 -0700
        Re: Arithmetic overflow checking David Lamb <dalamb@cs.queensu.ca> - 2011-07-12 08:29 -0400
      Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-12 13:18 +0200
      Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 11:39 -0700
        Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-12 12:38 -0700
          Re: Arithmetic overflow checking markspace <-@.> - 2011-07-12 13:20 -0700
            Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 13:23 -0700
              Re: Arithmetic overflow checking Martin Gregorie <martin@address-in-sig.invalid> - 2011-07-12 21:08 +0000
                Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-12 14:48 -0700
                Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-12 15:24 -0700
                Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-12 16:09 -0700
                Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-13 10:38 -0700
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-13 11:00 -0700
                Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-13 12:16 -0700
                Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-13 13:10 -0700
                Re: Arithmetic overflow checking markspace <-@.> - 2011-07-13 13:21 -0700
                Re: Arithmetic overflow checking Keith Thompson <kst-u@mib.org> - 2011-07-13 13:41 -0700
                Re: Arithmetic overflow checking Robert Wessel <robertwessel2@yahoo.com> - 2011-07-14 21:10 -0500
                Re: Arithmetic overflow checking "io_x" <a@b.c.invalid> - 2011-07-15 11:57 +0200
                Re: Arithmetic overflow checking Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-07-15 04:36 -0700
      Re: Arithmetic overflow checking tm <thomas.mertes@gmx.at> - 2011-07-13 00:52 -0700
        Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-13 07:45 -0700

csiph-web