Re: Modern compilers for ye olde architectures

From	dave_thompson_2@comcast.net
Newsgroups	comp.compilers
Subject	Re: Modern compilers for ye olde architectures
Date	2021-11-14 15:04 -0500
Organization	A noiseless patient Spider
Message-ID	<21-11-002@comp.compilers> (permalink)
References	<21-10-007@comp.compilers> <21-10-012@comp.compilers>

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On Wed, 06 Oct 2021 07:56:59 GMT, anton@mips.complang.tuwien.ac.at
(Anton Ertl) wrote:
...
> As for the back-end, it seems to me that the major problem with the
> Z80 is that it does not have general-purpose registers; instead, many
> instructions deal with specific registers.  Many early architectures
> were like that, and assembly programmers could puzzle out good
> register assignments, but compilers were not particularly good at it.
> So eventually computer architects introduced machines with
> general-purpose registers like the PDP-11, the VAX, and the RISCs; ...

Eventually? PDP-11 was 7 years before Z-80, and 5 years before that
both PDP-6 and S/360 had 16 GPRs (& none 'wasted' as PC SP FP).

S/360 and PDP-11 did have floating-point registers separate, and at
least on the latter optional. (I believe there were 360 models listed
without FP, but heard that actual instances were about as rare as
PDP-6 without the 'option' for 0-17 to be registers instead of core.)
[Floating point was optional on the low end 360/22, /25, /30, and /40.
Considering what they were used for and how slow the FP was, e.g.,
on the /30 floating add was over 50us, multiply up to 400us, I expect
a lot of them skipped the floating point. Larger models all had it. -John]

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Modern compilers for ye olde architectures "Luke A. Guest" <laguest@archeia.com> - 2021-10-05 13:22 +0100
  Re: Modern compilers for ye olde architectures David Brown <david.brown@hesbynett.no> - 2021-10-05 19:59 +0200
  Re: Modern compilers for ye olde architectures Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2021-10-05 22:12 +0200
  Re: Modern compilers for ye olde architectures Derek Jones <derek@NOSPAM-knosof.co.uk> - 2021-10-06 01:26 +0100
    Re: Modern compilers for ye olde architectures "Luke A. Guest" <laguest@archeia.com> - 2021-10-06 09:00 +0100
  Re: Modern compilers for ye olde architectures anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2021-10-06 07:56 +0000
    Re: Modern compilers for ye olde architectures Philipp Klaus Krause <pkk@spth.de> - 2021-10-06 18:20 +0200
      Re: Modern compilers for ye olde architectures anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2021-10-15 07:37 +0000
        Re: Modern compilers for ye olde architectures Philipp Klaus Krause <pkk@spth.de> - 2021-10-18 08:35 +0200
        Re: Modern compilers for ye olde architectures Philipp Klaus Krause <pkk@spth.de> - 2021-10-18 08:56 +0200
        Re: Modern compilers for ye olde architectures Philipp Klaus Krause <pkk@spth.de> - 2021-10-18 09:17 +0200
          Re: Modern compilers for ye olde architectures gah4 <gah4@u.washington.edu> - 2021-10-21 21:53 -0700
            Re: Modern compilers for ye olde architectures Kaz Kylheku <480-992-1380@kylheku.com> - 2021-10-22 17:28 +0000
    Re: Modern compilers for ye olde architectures dave_thompson_2@comcast.net - 2021-11-14 15:04 -0500
  Re: Modern compilers for ye olde architectures Theo <theom+news@chiark.greenend.org.uk> - 2021-10-06 10:36 +0100
    Re: Modern compilers for ye olde architectures "Luke A. Guest" <laguest@archeia.com> - 2021-10-06 16:20 +0100

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