From: John Cowan <cowan@ccil.org>
To: Tom Ivar Helbekkmo <tih@hamartun.priv.no>
Cc: TUHS main list <tuhs@minnie.tuhs.org>,
Douglas McIlroy <douglas.mcilroy@dartmouth.edu>
Subject: Re: [TUHS] PL/I stuff - was: Book Recommendation
Date: Fri, 26 Nov 2021 16:22:15 -0500 [thread overview]
Message-ID: <CAD2gp_SY+h88i=zduugJCMS1Bpc7UO6jAUQur9mqTqzg0p-WuQ@mail.gmail.com> (raw)
In-Reply-To: <m2sfviirs3.fsf@thuvia.hamartun.priv.no>
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On Fri, Nov 26, 2021 at 3:32 PM Tom Ivar Helbekkmo via TUHS <
tuhs@minnie.tuhs.org> wrote:
Is there any relationship, other than pure coincidence, between this
> naming scheme and DEC's F, G, and H floating point number formats?
>
I don't think so. The System/360 letters referred specifically to the
amount of memory available, so a D compiler would run on a D machine with
256K, and E/F/G were 512K/1M/2M.
The DEC floats were an extension of Fortran's exponent letters: D=double,
E=generic, F=single. G is a variant of F with a different
mantissa/exponent balance, and H is double double. S and T floats came
later and were bit-for-bit compatible with IEEE binary32 and binary64
formats. Lisp went a different way: to D, E, F they added S for small
floats and L for large floats.
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next prev parent reply other threads:[~2021-11-26 21:24 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 23:54 Douglas McIlroy
2021-11-25 16:35 ` Paul Winalski
2021-11-25 18:15 ` Steve Nickolas
2021-11-26 16:59 ` Paul Winalski
2021-11-26 20:30 ` Tom Ivar Helbekkmo via TUHS
2021-11-26 21:22 ` John Cowan [this message]
2021-11-27 0:01 ` George Michaelson
2021-11-27 16:12 ` Paul Winalski
-- strict thread matches above, loose matches on Subject: below --
2021-11-27 15:25 Noel Chiappa
2021-11-27 15:53 ` Charles H Sauer
2021-11-16 14:57 [TUHS] " Douglas McIlroy
2021-11-23 2:28 ` Mary Ann Horton
2021-11-23 21:54 ` Thomas Paulsen
2021-11-24 15:18 ` Richard Salz
2021-11-24 22:19 ` Charles Anthony
2021-11-24 22:29 ` [TUHS] PL/I stuff - was: " Will Senn
2021-11-24 23:00 ` Rob Pike
2021-11-24 23:13 ` Richard Salz
2021-11-25 1:48 ` Nelson H. F. Beebe
2021-11-25 2:03 ` George Michaelson
2021-11-25 14:47 ` Clem Cole
2021-11-26 22:20 ` Alan Glasser
2021-11-26 22:33 ` Alan Glasser
2021-11-27 0:23 ` Dennis Boone
2021-11-27 0:30 ` Larry McVoy
2021-11-27 0:47 ` Charles H. Sauer
2021-11-27 2:43 ` Alan Glasser
2021-11-27 0:56 ` Warner Losh
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