Re: Handling numeric types in interpreter

From	glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups	comp.lang.c
Subject	Re: Handling numeric types in interpreter
Date	2015-07-29 14:58 +0000
Organization	Aioe.org NNTP Server
Message-ID	<mpapn9$sf6$1@speranza.aioe.org> (permalink)
References	(8 earlier) <mp8mes$hqh$1@dont-email.me> <mp8qh3$3g5$1@dont-email.me> <lnzj2glzxm.fsf@kst-u.example.com> <mp9261$7qb$1@speranza.aioe.org> <mpa8cs$9uc$2@dont-email.me>

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jacobnavia <jacob@jacob.remcomp.fr> wrote:

(snip, I wrote, regarding x87 floating point)
>> In addition, there are surprising results when the compiler does
>> keep intermediate values in registers. As there are a limited
>> number, it might not keep all intermediate values in registers,
>> so you get different values for the same expression.

>> Also, optimization might keep values in registers between
>> statements, again surprising the user.

> lcc-win avoids all those troubles by maintaining long doubles in the FPU 
> registers, and doubles in the SSE registers. That way, there are no 
> surprises.

The original idea for the 8087 was a virtual stack. That it would
interrupt when the stack got full, the interrupt routine would 
write some registers to memory somewhere, and continue on. 
On stack underflow, they would be restored, and programs could
run independent of the actual (8 element) stack. 

But no-one tried to write the interrupt routine until the 8087
was done, and it turned out not to be possible. I don't reemmber
the exact details, but they are related to restoring some of 
the state bits. You can load and store registers, but not some
other bits that are needed.

-- glen

Thread

Handling numeric types in interpreter luser droog <luser.droog@gmail.com> - 2015-07-13 19:33 -0700
  Re: Handling numeric types in interpreter jacobnavia <jacob@jacob.remcomp.fr> - 2015-07-14 07:31 +0200
  Handling numeric types in interpreter asetofsymbols@gmail.com - 2015-07-14 00:35 -0700
  Re: Handling numeric types in interpreter David Kleinecke <dkleinecke@gmail.com> - 2015-07-14 08:55 -0700
  Re: Handling numeric types in interpreter Bartc <bc@freeuk.com> - 2015-07-15 23:18 +0100
    Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-24 00:21 -0700
      Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-24 08:36 -0700
        Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-24 11:04 -0700
          Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-24 12:25 -0700
            Re: Handling numeric types in interpreter James Kuyper <jameskuyper@verizon.net> - 2015-07-24 22:21 -0400
              Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 02:28 -0700
                Re: Handling numeric types in interpreter Bartc <bc@freeuk.com> - 2015-07-25 15:16 +0100
                Re: Handling numeric types in interpreter Richard Damon <Richard@Damon-Family.org> - 2015-07-25 11:03 -0400
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-25 10:05 -0700
              Re: Handling numeric types in interpreter gazelle@shell.xmission.com (Kenny McCormack) - 2015-07-25 12:32 +0000
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 06:12 -0700
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-25 10:08 -0700
                Re: Handling numeric types in interpreter ais523 <ais523@nethack4.org> - 2015-07-28 17:50 +0000
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-28 11:52 -0700
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-28 12:25 -0700
                Re: Handling numeric types in interpreter Richard Heathfield <rjh@cpax.org.uk> - 2015-07-28 20:52 +0100
                Re: Handling numeric types in interpreter jacobnavia <jacob@jacob.remcomp.fr> - 2015-07-28 23:01 +0200
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-28 14:44 -0700
                Re: Handling numeric types in interpreter Ian Collins <ian-news@hotmail.com> - 2015-07-29 09:43 +1200
                Re: Handling numeric types in interpreter glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-28 23:10 +0000
                Re: Handling numeric types in interpreter Ian Collins <ian-news@hotmail.com> - 2015-07-29 12:04 +1200
                Re: Handling numeric types in interpreter Melzzzzz <mel@zzzzz.com> - 2015-07-29 02:39 +0200
                Re: Handling numeric types in interpreter jacobnavia <jacob@jacob.remcomp.fr> - 2015-07-29 12:04 +0200
                Re: Handling numeric types in interpreter glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-29 14:58 +0000
                Re: Handling numeric types in interpreter jacobnavia <jacob@jacob.remcomp.fr> - 2015-07-29 14:14 +0200
                Re: Handling numeric types in interpreter Bartc <bc@freeuk.com> - 2015-07-29 13:29 +0100
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-29 08:48 -0700
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-29 08:45 -0700
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-28 16:28 -0700
                Re: Handling numeric types in interpreter jacobnavia <jacob@jacob.remcomp.fr> - 2015-07-29 12:02 +0200
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-29 08:51 -0700
                Re: Handling numeric types in interpreter jacobnavia <jacob@jacob.remcomp.fr> - 2015-07-29 18:35 +0200
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-29 10:47 -0700
                Re: Handling numeric types in interpreter Robert Wessel <robertwessel2@yahoo.com> - 2015-07-25 15:46 -0500
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 14:08 -0700
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-25 15:42 -0700
                Re: Handling numeric types in interpreter Robert Wessel <robertwessel2@yahoo.com> - 2015-07-26 00:31 -0500
                Re: Handling numeric types in interpreter James Kuyper <jameskuyper@verizon.net> - 2015-07-25 17:48 -0400
                Re: Handling numeric types in interpreter Robert Wessel <robertwessel2@yahoo.com> - 2015-07-25 17:31 -0500
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 15:57 -0700
                Re: Handling numeric types in interpreter Bartc <bc@freeuk.com> - 2015-07-26 01:07 +0100
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 17:26 -0700
                Re: Handling numeric types in interpreter Richard Damon <Richard@Damon-Family.org> - 2015-07-25 22:25 -0400
                Re: Handling numeric types in interpreter James Kuyper <jameskuyper@verizon.net> - 2015-07-25 19:04 -0400
                Re: Handling numeric types in interpreter Robert Wessel <robertwessel2@yahoo.com> - 2015-07-26 00:23 -0500
                Re: Handling numeric types in interpreter James Kuyper <jameskuyper@verizon.net> - 2015-07-26 08:24 -0400
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-26 06:36 -0700
                Re: Handling numeric types in interpreter Robert Wessel <robertwessel2@yahoo.com> - 2015-07-26 16:30 -0500
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-26 15:42 -0700
                Re: Handling numeric types in interpreter Robert Wessel <robertwessel2@yahoo.com> - 2015-07-26 16:28 -0500
                Re: Handling numeric types in interpreter James Kuyper <jameskuyper@verizon.net> - 2015-07-26 18:57 -0400
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-26 16:20 -0700
                Re: Handling numeric types in interpreter Keith Thompson <kst-u@mib.org> - 2015-07-25 15:58 -0700
              Re: Handling numeric types in interpreter James Kuyper <jameskuyper@verizon.net> - 2015-07-25 12:56 -0400
                Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 14:18 -0700
      Re: Handling numeric types in interpreter glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-24 18:06 +0000
        Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-24 11:16 -0700
          Re: Handling numeric types in interpreter glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-24 23:06 +0000
            Re: Handling numeric types in interpreter Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-24 16:21 -0700
  Re: Handling numeric types in interpreter Michael Angelo Ravera <maravera@prodigy.net> - 2015-07-15 19:13 -0700
    Re: Handling numeric types in interpreter luser droog <luser.droog@gmail.com> - 2015-07-23 08:36 -0700

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