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Re: What form of executable or load module for your OS?

From "James Harris" <james.harris.1@gmail.com>
Newsgroups alt.os.development
Subject Re: What form of executable or load module for your OS?
Date 2015-07-03 22:45 +0100
Organization A noiseless patient Spider
Message-ID <mn6vm9$g5a$1@dont-email.me> (permalink)
References (5 earlier) <75acded2-9f64-4d9f-81c2-7ec73fd72e01@googlegroups.com> <mn5dto$q6c$1@dont-email.me> <1687b850-3c16-44ec-9bd9-4eb0dc2a201b@googlegroups.com> <mn5o0b$uv1$1@dont-email.me> <op.x07tovymyfako5@localhost>

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"Rod Pemberton" <boo@fasdfrewar.cdm> wrote in message 
news:op.x07tovymyfako5@localhost...
> On Fri, 03 Jul 2015 06:27:42 -0400, James Harris 
> <james.harris.1@gmail.com> wrote:
>> "Alexei A. Frounze" <alexfrunews@gmail.com> wrote in message 
>> news:1687b850-3c16-44ec-9bd9-4eb0dc2a201b@googlegroups.com...
>>> On Friday, July 3, 2015 at 12:35:41 AM UTC-7, James Harris wrote:

...

>>>> I wish. AIUI yours won't generate 8086 code but assumes a later 
>>>> CPU.

...

> IIRC, Alexei said SmallerC can emit NASM.  If so, you only need add
> a NASM directive to the assembly, i.e., CPU 8086, to have NASM tell
> you which instructions are incorrect for 8086.  If the C code is
> minimal, e.g., bootloader or bootsector, then it's not really that
> much assembly to rework by hand.

It's an idea but then I would have to "rework by hand" each time I added 
a new module and each time I recompiled any existing module. That's not 
really a starter. At the moment I use bcc to generate 8086 code and it 
does all that for me, albeit that it generates as86 object files which 
is rather an obscure format.

> Or, you could do like Ben and
> customize SmallerC.  I.e., you could adjust the assembly selection
> code of SmallerC to not use 386 or later instructions.

I have thought about that and Alex has offered to give me some pointers 
to get me started but it would take me a lot of time to do.

Other things I have considered for this and related purposes: bug-fixing 
bcc, converting bcc's as86 output to something more widely used (either 
via bespoke code or using GNU's BFD library), writing a separate 
compiler, post-processing other output etc. But all would take a lot of 
time.

> Just how
> many more advanced x86 instructions could Alexei really use? ...
> The basic x86 instructions were set before the 386.

I don't know what he emits that is not 8086 compatible. Could it be more 
than just a few instructions? Off the top of my head

  pusha/popa
  shifts and rotates immediate by more than 1
  push immediate
  registers wider than 16 bits

You could probably add more. None of those are available to 8086 code.

James

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Thread

Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-06-25 21:20 -0700
  Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-01 10:36 +0100
    Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-01 21:07 -0700
      Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-02 23:35 -0700
        Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-03 08:35 +0100
          Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-03 02:49 -0700
            Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-03 11:27 +0100
              Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-03 16:54 -0400
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-03 22:45 +0100
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-03 17:56 -0400
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-03 15:28 -0700
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-03 23:48 +0100
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-03 21:52 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-04 04:00 -0400
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-04 04:42 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-05 02:12 -0400
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-05 00:47 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-05 05:28 -0400
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-05 02:58 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-06 06:21 -0400
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-07 01:44 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-07 05:40 -0400
                Re: What form of executable or load module for your OS? "Kerr Mudd-John" <admin@127.0.0.1> - 2015-07-07 14:02 +0100
                Re: What form of executable or load module for your OS? "wolfgang kern" <nowhere@never.at> - 2015-07-07 18:13 +0200
                Re: What form of executable or load module for your OS? "Kerr Mudd-John" <notsaying@invalid.org> - 2015-07-08 12:54 -0100
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-09 13:19 +0100
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-07 22:10 -0700
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-08 08:48 +0100
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-08 23:53 -0700
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-09 17:29 +0100
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-10 01:01 -0700
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-10 13:46 +0100
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-10 00:59 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-08 03:52 -0400
                Re: What form of executable or load module for your OS? "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-08 06:46 -0700
                Re: What form of executable or load module for your OS? "James Harris" <james.harris.1@gmail.com> - 2015-07-09 13:16 +0100
                Re: What form of executable or load module for your OS? "s_dubrovich@yahoo.com" <s_dubrovich@yahoo.com> - 2015-07-11 09:57 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-13 02:47 -0400
                Re: What form of executable or load module for your OS? "s_dubrovich@yahoo.com" <s_dubrovich@yahoo.com> - 2015-07-14 07:39 -0700
                Re: What form of executable or load module for your OS? "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-15 02:37 -0400
        Code insanity "Mike Gonta" <mikegonta@gmail.com> - 2015-07-03 03:47 -0400
          Re: Code insanity "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-03 02:57 -0700
          Re: Code insanity (was: What form of executable or load module for your OS?) "James Harris" <james.harris.1@gmail.com> - 2015-07-03 11:35 +0100

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