Re: C arithmetic, was Software proofs, was Are there different

From	gah4 <gah4@u.washington.edu>
Newsgroups	comp.compilers
Subject	Re: C arithmetic, was Software proofs, was Are there different
Date	2023-02-09 00:26 -0800
Organization	Compilers Central
Message-ID	<23-02-035@comp.compilers> (permalink)
References	(2 earlier) <23-02-019@comp.compilers> <23-02-025@comp.compilers> <23-02-026@comp.compilers> <23-02-029@comp.compilers> <23-02-032@comp.compilers>

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On Wednesday, February 8, 2023 at 8:48:23 AM UTC-8, gah4 wrote:

(snip)

> Well, I have been wondering for years when we get a C compiler
> for the 7090 so we can test out sign-magnitude integers.

> I think the 7090 does 16 bit integers, at least that is what
> its Fortran compilers did, stored in 36 bit words.

 (snip)

> [The 704x/709x series did 36 bit sign-magnitude arithmetic. Fortran
> integers were limited to 15 bits plus a sign, probably because that
> was the size of addresses, and they expected integer arithmetic to
> be used only for counting and subscripts. In 709 Fortran II they
> expanded them to 17 bits, in 7090 Fortran IV they were finally a
> full word. -John]

OK, so 7090 C can use all 36 bits.  When we get one.

I just remembered that the S/360 emulation to develop
OS/360 was done on the 7090.  36 bits would help!

It was the 15 bit integers on the 704 that gave us five digit
statement numbers in Fortran, originally 1 to 32767, and
(not much) later extended to 99999.

And over 60 years later, we still have 99999.

But also, the 704 Fortran, and I believe still the 7090,
indexes arrays from the end of memory toward the beginning.
[It did because for reasons I have never been able to figure out,
the 70x series subtracted rather than added the contents of
an index register to get the effective address. -John]

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Re: Are there different programming languages that are compiled to the same intermediate language? Martin Ward <mwardgkc@gmail.com> - 2023-01-31 14:04 +0000
  Re: Are there different programming languages that are compiled to the same intermediate language? arnold@freefriends.org (Aharon Robbins) - 2023-02-01 08:07 +0000
    Re: Software proofs, was Are there different programming languages that are compiled to the same intermediate language? Spiros Bousbouras <spibou@gmail.com> - 2023-02-05 15:14 +0000
      Re: C arithmetic, was Software proofs, was Are there different Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-02-05 16:14 -0800
        Re: C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-06 13:26 -0800
          Re: C arithmetic, was Software proofs, was Are there different Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2023-02-07 14:31 +0100
            Re: C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-08 01:10 -0800
              Re: C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-09 00:26 -0800
                Re: C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-11 00:01 -0800
                Re: C arithmetic, was Software proofs, was Are there different drb@ihatespam.msu.edu (Dennis Boone) - 2023-02-12 04:37 +0000
            Re: C arithmetic, was Software proofs, was Are there different anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2023-02-08 10:19 +0000
              Re: C arithmetic, was Software proofs, was Are there different Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2023-02-10 19:11 +0100
                Re: C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-10 23:47 -0800
                Re: C arithmetic, was Software proofs, was Are there different anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2023-02-11 22:34 +0000
                Re: old floating point, C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-11 22:48 -0800
            Re: C arithmetic, was Software proofs, was Are there different Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2023-02-08 15:24 +0100
              Re: C arithmetic, was Software proofs, was Are there different gah4 <gah4@u.washington.edu> - 2023-02-09 00:37 -0800

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