Re: Portable Assembly

From	Stefan Reuther <stefan.news@arcor.de>
Newsgroups	comp.arch.embedded
Subject	Re: Portable Assembly
Date	2017-05-29 18:43 +0200
Message-ID	<oghq3m.4ts.1@stefan.msgid.phost.de> (permalink)
References	<ogckfb$qcb$1@dont-email.me> <ogcq6o$cf0$1@dont-email.me> <ogcr17$ft7$1@dont-email.me> <ogf5sb.vg.1@stefan.msgid.phost.de> <ogf28t$k9o$1@dont-email.me>

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Am 28.05.2017 um 19:47 schrieb Dimiter_Popoff:
> On 28.5.2017 г. 19:45, Stefan Reuther wrote:
>> Am 27.05.2017 um 23:31 schrieb Dimiter_Popoff:
>>> However, they are by far not what a "portable assembler" - existing
>>> under the name Virtual Processor Assembler in our house is.
>>> And never will be, like any high level language C is yet another
>>> phrase book - convenient when you need to do a quick interaction
>>> when you don't speak the language - and only then.
>>
>> So, then, what is a portable assembler?
> 
> One which is not tied to a particular architecture, rather to an
> idealized machine model.

So, to what *is* it tied then? What is its *concrete* machine model?

> It makes sense to use this assuming that processors evolve towards
> better, larger register sets - which has been the case last few
> decades. It would be impractical to try to assemble something written
> once for say 68k and then assemble it for a 6502 - perhaps doable but
> insane.

Doable and not insane with C.

Actually, you can programm the 6502 in C++17.

>> One major variable of a processor architecture is the number of
>> registers, and what you can do with them. On one side of the spectrum,
>> we have PICs or 6502 with pretty much no registers, on the other side,
>> there's things like x86_64 or ARM64 with plenty 64-bit registers. Using
>> an abstraction like C to let the compiler handle the distinction (which
>> register to use, when to spill) sounds like a pretty good idea to me.
> 
> Using a phrase book is of course a good idea if you want to conduct
> a quick conversation.
> It is a terrible idea if you try to use the language for years and
> choose to stay confined within the phrases you have in the book.

My point being: if you work on assembler level, that is: registers,
you'll not have anything more than a phrase book. A C compiler can use
knowledge from one phrase^Wstatement and carry it into the next, and it
can use grammar to generate not only "a = b + c" and "x = y * z", but
also "a = b + (y*z)".

>> If you were more close to assembler, you'd either limit yourself to an
>> unuseful subset that works everywhere, or to a set that works only in
>> one or two places.
> 
> Like I said before, there is no point to write code which can work
> on any processor ever made. I have no time to waste on that, I just need
> my code to be working on what is the best silicon available. This
> used to be 68k, now it is power. You have to program with some
> constraints - e.g. knowing that the "assembler" (which in reality
> is more a compiler) may use r3-r4 as it wishes and not preserve
> them on a per line basis etc.

I am not an expert in either of these two architectures, but 68k has 8
data + 8 address registers whereas Power has 32 GPRs. If you work on a
virtual pseudo-assembler level you probably ignore most of your Power.

A classic compiler will happily use as many registers as it finds useful.

The only possible gripe with C would be that it has no easy way to write
a memory cell by number. But a simple macro fixes that.


  Stefan

Thread

Portable Assembly rickman <gnuarm@gmail.com> - 2017-05-27 15:39 -0400
  Re: Portable Assembly Grant Edwards <invalid@invalid.invalid> - 2017-05-27 21:05 +0000
    Re: Portable Assembly Mel Wilson <mwilson@the-wire.com> - 2017-05-27 21:29 +0000
    Re: Portable Assembly upsidedown@downunder.com - 2017-05-28 00:36 +0300
      Re: Portable Assembly Grant Edwards <invalid@invalid.invalid> - 2017-05-27 21:56 +0000
        Re: Portable Assembly Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2017-05-28 14:36 +0200
      Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-05-29 09:53 +0200
  Re: Portable Assembly Les Cargill <lcargill99@comcast.com> - 2017-05-27 16:17 -0500
    Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-28 00:31 +0300
      Re: Portable Assembly Theo Markettos <theom+news@chiark.greenend.org.uk> - 2017-05-27 22:52 +0100
        Re: Portable Assembly Grant Edwards <invalid@invalid.invalid> - 2017-05-27 21:58 +0000
          Re: Portable Assembly upsidedown@downunder.com - 2017-05-28 07:37 +0300
            Re: Portable Assembly rickman <gnuarm@gmail.com> - 2017-05-28 01:28 -0400
            Re: Portable Assembly Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-28 07:33 +0100
              Re: Portable Assembly rickman <gnuarm@gmail.com> - 2017-05-28 03:22 -0400
                Re: Portable Assembly Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-05-28 08:49 +0100
                Re: Portable Assembly upsidedown@downunder.com - 2017-05-28 15:03 +0300
          Re: Portable Assembly Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-05-28 12:26 +0300
        Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-28 01:04 +0300
        Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-05-29 10:43 +0200
          Re: Portable Assembly Anssi Saari <as@sci.fi> - 2017-05-31 10:19 +0300
            Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-31 01:49 -0700
            Re: Portable Assembly Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-05-31 15:56 +0300
        Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-29 02:33 -0700
          Re: Portable Assembly upsidedown@downunder.com - 2017-05-29 23:46 +0300
            Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-29 13:54 -0700
      Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-27 15:52 -0700
        Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-28 02:14 +0300
          Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-27 17:14 -0700
            Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-28 03:38 +0300
              Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-27 18:42 -0700
      Re: Portable Assembly Stefan Reuther <stefan.news@arcor.de> - 2017-05-28 18:45 +0200
        Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-28 20:47 +0300
          Re: Portable Assembly Stefan Reuther <stefan.news@arcor.de> - 2017-05-29 18:43 +0200
            Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-29 10:23 -0700
            Re: Portable Assembly "Boudewijn Dijkstra" <sp4mtr4p.boudewijn@indes.com> - 2017-05-30 16:31 +0200
        Re: Portable Assembly Grant Edwards <invalid@invalid.invalid> - 2017-05-29 01:59 +0000
          Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-29 05:21 +0300
      Re: Portable Assembly Les Cargill <lcargill99@comcast.com> - 2017-05-28 22:04 -0500
        Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-29 02:57 -0700
      Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-05-29 11:00 +0200
        Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-29 15:08 +0300
          Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-05-29 15:06 +0200
            Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-29 20:02 +0300
              Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-05-29 23:13 +0200
                Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-30 16:53 +0300
                Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-05-31 11:36 +0200
                Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-01 22:43 +0300
                Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-06-02 13:27 +0200
          Re: Portable Assembly Grant Edwards <invalid@invalid.invalid> - 2017-05-29 13:48 +0000
    Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-05-27 15:46 -0700
    Re: Portable Assembly Tim Wescott <tim@seemywebsite.really> - 2017-05-28 23:59 -0500
  Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-05-28 00:23 +0300
  Re: Portable Assembly jim.brakefield@ieee.org - 2017-05-27 16:54 -0700
  Re: Portable Assembly Walter Banks <walter@bytecraft.com> - 2017-05-29 17:23 -0400
  Re: Portable Assembly "Boudewijn Dijkstra" <sp4mtr4p.boudewijn@indes.com> - 2017-06-02 17:03 +0200
    Re: Portable Assembly Mike Perkins <spam@spam.com> - 2017-06-05 15:39 +0100
      Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-06-05 18:10 +0200
      Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-05 09:10 -0700
        Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-06 00:24 -0400
          Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-06-06 11:05 +0200
          Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-06 07:03 -0700
            Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-06-06 16:58 +0200
              Re: Portable Assembly Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-06-06 21:26 +0300
            Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-06 16:42 -0400
              Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-06 23:16 -0700
                Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-08 06:38 -0400
                Re: Portable Assembly Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-08 15:58 +0300
                Re: Portable Assembly upsidedown@downunder.com - 2017-06-08 21:34 +0300
                Re: Portable Assembly Les Cargill <lcargill99@comcast.com> - 2017-06-10 15:27 -0500
                Re: Portable Assembly Les Cargill <lcargill99@comcast.com> - 2017-06-10 15:23 -0500
                Re: Portable Assembly Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-08 14:50 +0100
                Re: Portable Assembly Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-06-08 17:38 +0300
                Re: Portable Assembly Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-08 16:37 +0100
                Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-09 14:14 -0400
                Re: Portable Assembly Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-06-09 22:25 +0100
                Re: Portable Assembly Clifford Heath <no.spam@please.net> - 2017-06-10 09:54 +1000
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-09 00:06 -0700
                Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-09 22:14 -0400
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-09 22:50 -0700
                Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-10 21:01 -0400
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-11 00:39 -0700
                Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-12 23:27 -0400
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-12 22:42 -0700
                Re: Portable Assembly Ed Prochak <edprochak@gmail.com> - 2017-06-13 14:24 -0700
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-13 21:57 -0700
                Re: Portable Assembly Reinhardt Behm <rbehm@hushmail.com> - 2017-06-14 13:26 +0800
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-13 23:58 -0700
                Re: Portable Assembly Ed Prochak <edprochak@gmail.com> - 2017-06-19 06:48 -0700
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-19 16:45 -0700
                Re: Portable Assembly Ed Prochak <edprochak@gmail.com> - 2017-06-20 15:07 -0700
                Re: Portable Assembly Don Y <blockedofcourse@foo.invalid> - 2017-06-21 07:37 -0700
              Re: Portable Assembly David Brown <david.brown@hesbynett.no> - 2017-06-07 09:20 +0200
          Re: Portable Assembly Niklas Holsti <niklas.holsti@tidorum.invalid> - 2017-06-07 00:30 +0300
            Re: Portable Assembly George Neuner <gneuner2@comcast.net> - 2017-06-07 02:02 -0400

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