Re: Portable Assembly

From	Don Y <blockedofcourse@foo.invalid>
Newsgroups	comp.arch.embedded
Subject	Re: Portable Assembly
Date	2017-05-27 15:46 -0700
Organization	A noiseless patient Spider
Message-ID	<ogcvd1$uvi$1@dont-email.me> (permalink)
References	<ogckfb$qcb$1@dont-email.me> <ogcq6o$cf0$1@dont-email.me>

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On 5/27/2017 2:17 PM, Les Cargill wrote:
> That's what C is for.

Arguably, ANY HLL.

> This being said, I've been doing this for
> 37 years and have only a few times seen an actual need for
> portability - usually, the new hardware is so radically
> different that porting makes little sense.

Depends on how you handle your abstractions in the design.
If you tie the design directly to the hardware, then you've
implicitly made it dependent on that hardware -- without
even being aware of the dependencies.

OTOH, you can opt to create abstractions that give you a "slip sheet"
above the bare iron -- at some (small, if done well) cost in efficiency.
(e.g., "Hardware Abstraction Layer" -- though not necessarily as
explicit or limiting therein)

E.g., my current RTOS moves reasonably well between different hardware
platforms (I'm running on ARM and x86, currently) with the same sorts of
services exported to the higher level API's.

OTOH, the API's explicitly include provisions that allow the "application"
layers to tailor themselves to key bots of the hardware made largely
opaque by the API (e.g., MMU page sizes, number and granularity of hardware
timers, etc.)

But, this changes the level of proficiency required of folks working
with those API's.  Arguably, I guess it should (?)

Of course, if you want to shed all "hardware dependencies" and just code
to a POSIX API...  <shrug>

One could make an abstraction that is sufficiently *crude* (the equivalent of
single-transistor logic) and force the coder to use that as an implementation
language; then, recognize patterns of "operations" and map those to templates
that correlate with opcodes of a particular CPU (i.e., many operations -> one
opcode).  Or, the HLL approach of mapping *an* operation into a sequence of
CPU-specific opcodes.  Or, many<->many, in between.

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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