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From: Paul Eggert <eggert@cs.ucla.edu>
To: rms@gnu.org
Cc: luangruo@yahoo.com, ulm@gentoo.org, eliz@gnu.org,
	contovob@tcd.ie, emacs-devel@gnu.org
Subject: Re: Lisp reader syntax and bootstrap
Date: Sat, 15 Jul 2023 08:22:20 -0700	[thread overview]
Message-ID: <de9304c0-e976-74fa-afe5-5cafa2b921ef@cs.ucla.edu> (raw)
In-Reply-To: <E1qKUjq-0001ZI-5S@fencepost.gnu.org>

On 2023-07-14 19:10, Richard Stallman wrote:
> That's a bit of a kludge -- using those values might be wrong for
> some purposes...

Yes, though there are similar problems even for finite numbers, since 
they also behave differently on the VAX, sometimes significantly. E.g., 
VAX subtraction can underflow to zero via catastrophic cancellation, 
whereas IEEE subtraction cannot.

Though my change is indeed a hack, it is an improvement in that Emacs 
can now start up and load 'calculator' whereas formerly it could not. I 
"tested" this by manually setting IEEE_FLOATING_POINT to zero on x86-64, 
and compiling and running the result. Of course this is not the same as 
a real VAX.


>    > This patch shouldn't change behavior (or even the executable code) on
>    > today's platforms. It's purely for computer museums.
> 
> If that's true, maybe your solution is fine.

I surveyed the net and it appears to be true. The only Emacs platform 
that still insists on non-IEEE floating point is NetBSD/vax, and 
nowadays that platform seems to be run only for computer-museum-like 
purposes. These uses are rare even by computer-museum standards, as most 
hobbyist historians that simulate VAXes seem to prefer VMS to NetBSD, I 
expect partly because VMS "feels" older (it differs more from GNU :-). 
And VMS-using hobbyists can't run current Emacs, as Emacs 23 dropped VMS 
support.

PS. Are you aware of the licensing dispute over the emulator that 
hobbyists typically use to run VAX code? This emulator, SIMH, is based 
on software that dates back to the 1960s, so in some sense it's even 
older than Emacs. The dispute involves a license clause introduced a 
year ago that I've not seen before, and it's not clear to me that SIMH 
is free software any more. However, this change has been disputed and 
SIMH has forked off a new project Open SIMH that does not have the 
controversial clause. For details, please see:

https://groups.io/g/simh/topic/91528716#1659

The disputed licensing clause is at the end of this change:

https://github.com/simh/simh/commit/ce2adce632e1a22e6d76d4bf726d6b863373c550




  parent reply	other threads:[~2023-07-15 15:22 UTC|newest]

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-23 11:46 Disambiguate modeline character for UTF-8? Ulrich Mueller
2020-08-23 15:27 ` Stefan Monnier
2020-08-23 16:07   ` Eli Zaretskii
2020-08-23 18:24     ` Paul Eggert
2020-08-23 18:53       ` Ulrich Mueller
2020-08-23 18:56         ` Eli Zaretskii
2020-08-23 18:57         ` Eli Zaretskii
2020-08-23 19:13           ` Ulrich Mueller
2020-08-23 19:42             ` Eli Zaretskii
2020-08-23 21:23               ` Stefan Monnier
2020-08-24  7:06                 ` Ulrich Mueller
2020-08-24 14:30                   ` Yuri Khan
2020-08-29 11:17                     ` Ulrich Mueller
2020-08-24 14:36                   ` Drew Adams
2020-08-24 15:23                     ` Ulrich Mueller
2020-08-24 16:43                       ` Stefan Monnier
2023-07-05 10:08                       ` Ulrich Mueller
2023-07-05 11:41                         ` Eli Zaretskii
2023-07-05 13:04                           ` Ulrich Mueller
2023-07-05 13:44                             ` Eli Zaretskii
2023-07-05 21:50                               ` Ulrich Mueller
2023-07-05 22:11                                 ` Paul Eggert
2023-07-06  8:51                                   ` Ulrich Mueller
2023-07-06  5:33                                 ` Eli Zaretskii
2023-07-06  8:47                                   ` Ulrich Mueller
2023-07-06  9:20                                     ` Eli Zaretskii
2023-07-06  9:46                                       ` Ulrich Mueller
2023-07-06 12:34                                         ` Po Lu
2023-07-06 12:32                                     ` Po Lu
2023-07-06 12:31                                 ` Po Lu
2023-07-06 13:02                                   ` Andreas Schwab
2023-07-06 13:08                                   ` Ulrich Mueller
2023-07-06 17:37                                     ` Paul Eggert
2023-07-06 18:13                                       ` Eli Zaretskii
2023-07-06 18:44                                       ` Ulrich Müller
2023-07-06 19:01                                         ` Eli Zaretskii
2023-07-06 19:31                                           ` Ulrich Mueller
2023-07-07  5:18                                             ` Eli Zaretskii
2023-07-07  5:48                                               ` Ulrich Müller
2023-07-07  6:16                                                 ` Po Lu
2023-07-07  6:41                                                   ` Ulrich Mueller
2023-07-07  7:38                                                     ` Po Lu
2023-07-07  9:44                                                       ` Ulrich Mueller
2023-07-07 10:21                                                         ` Eli Zaretskii
2023-07-07 10:42                                                           ` Ulrich Mueller
2023-07-07 12:04                                                             ` Po Lu
2023-07-07 13:01                                                               ` Ulrich Mueller
2023-07-07 13:38                                                                 ` Po Lu
2023-07-07 12:01                                                         ` Po Lu
2023-07-07 12:38                                                           ` Andreas Schwab
2023-07-07 13:37                                                             ` Po Lu
2023-07-07 13:45                                                               ` Andreas Schwab
2023-07-07 12:58                                                           ` Eli Zaretskii
2023-07-08  8:49                                                 ` Eli Zaretskii
2023-07-08 15:27                                                   ` Basil Contovounesios
2023-07-08 15:38                                                     ` Eli Zaretskii
2023-07-08 16:21                                                       ` Basil Contovounesios
2023-07-08 16:33                                                         ` Eli Zaretskii
2023-07-08 16:57                                                           ` Basil Contovounesios
2023-07-08 18:21                                                         ` Ulrich Mueller
2023-07-08 21:31                                                           ` Basil Contovounesios
2023-07-09  9:22                                                       ` Lisp reader syntax and bootstrap (was: Re: Disambiguate modeline character for UTF-8?) Ulrich Mueller
2023-07-09  9:57                                                         ` Lisp reader syntax and bootstrap Po Lu
2023-07-13  2:04                                                           ` Richard Stallman
2023-07-13  4:27                                                             ` Po Lu
2023-07-13 22:07                                                               ` Paul Eggert
2023-07-14  5:05                                                                 ` Ulrich Mueller
2023-07-14  6:57                                                                   ` Paul Eggert
2023-07-15  2:10                                                                 ` Richard Stallman
2023-07-15  2:38                                                                   ` Po Lu
2023-07-15  5:18                                                                     ` Philip Kaludercic
2023-07-15  5:50                                                                       ` Po Lu
2023-07-15 15:22                                                                   ` Paul Eggert [this message]
2023-07-17  2:22                                                                     ` Richard Stallman
2023-07-17  5:26                                                                       ` Paul Eggert
2023-07-17  2:32                                                                     ` Po Lu
2023-07-16  2:19                                                               ` Richard Stallman
2023-07-09 11:35                                                         ` Lisp reader syntax and bootstrap (was: Re: Disambiguate modeline character for UTF-8?) Eli Zaretskii
2023-07-07  0:19                                     ` Disambiguate modeline character for UTF-8? Po Lu
2023-07-06 12:27                             ` Po Lu
2023-07-07  7:09                               ` UTF-32 (was: Re: Disambiguate modeline character for UTF-8?) Ulrich Mueller
2023-07-07  7:34                                 ` Eli Zaretskii
2023-07-07  8:20                                   ` UTF-32 Ulrich Mueller
2023-07-07 10:16                                     ` UTF-32 Eli Zaretskii
2023-07-07 10:34                                       ` UTF-32 Ulrich Mueller
2023-07-07 12:49                                         ` UTF-32 Eli Zaretskii
2023-07-07 13:24                                           ` UTF-32 Andreas Schwab
2023-07-07 13:36                                           ` UTF-32 Ulrich Mueller
2023-07-07 14:06                                             ` UTF-32 Eli Zaretskii
2023-07-05 12:49                         ` Disambiguate modeline character for UTF-8? Stefan Monnier
2023-07-05 13:38                           ` Eli Zaretskii
2023-07-06 19:07                           ` Filipp Gunbin
2020-08-23 19:47             ` Stefan Kangas
2020-08-24 18:35     ` Juri Linkov
2020-08-24 18:55       ` Eli Zaretskii
2020-08-25 18:59         ` Juri Linkov
2020-08-25 19:26           ` Eli Zaretskii

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