From: Jacob Ritorto <jacob.ritorto@gmail.com>
To: Ronald Natalie <ron@ronnatalie.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] as(1) on Ultrix-11 vs 2.11BSD
Date: Tue, 28 Apr 2020 20:17:54 -0400 [thread overview]
Message-ID: <CAHYQbfBPgLKLGeGL=wLBQLOhXqLd0AfpRZOpfJi_7hjo2aYc3w@mail.gmail.com> (raw)
In-Reply-To: <3642A182-45AA-43F8-A07B-8FAB69AD84A9@ronnatalie.com>
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On Tue, Apr 28, 2020 at 9:03 AM Ronald Natalie <ron@ronnatalie.com> wrote:
> Yes, you aren’t programming 2.11 BSD correctly.
>
Wow, I'd hoped it was that. Thank you so much! I spent way too much time
fiddling incorrectly.
Was an example I'd cobbled together from my college textbook I've been
going back through, _Assembly_Language_for_the_PDP-11_RT-RSX-UNIX_ (c)1981
Kapps and Stafford. We didn't have UNIX for the class so never ran into
this.
> Your examples are the older UNIX syscalls (your programs work correctly in
> Version 6 by the way as well).
>
> In 2.11 BSD, all the arguments for the syscalls are inline (i.e., none are
> passed in registers. This appears to be the beginnings of making the
> kernel protable across architectures.
> The systent table no longer has separate fields for args in registers and
> not in registers and the code in sys/pdp/trap.c doesn’t look at the
> registers anymore.
>
I wonder if the differences are written up somewhere. I did try to look
for more documentation but came up short. Must've been quite
well-ingrained in programmers' minds in the day.
> Proper code now should be:
> sys 4
> 1
> a
> 6
> sys 1
> 0
> Note your previous code used to just return 6 from the program (the return
> value of write).
>
Ah, so passing exit code as an arg to sys 1. Cool. Thanks again!
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next prev parent reply other threads:[~2020-04-29 0:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 1:56 Jacob Ritorto
2020-04-28 13:03 ` Ronald Natalie
2020-04-29 0:17 ` Jacob Ritorto [this message]
2020-04-29 0:54 ` ron
2020-04-29 2:26 Noel Chiappa
2020-04-29 4:08 ` Jacob Ritorto
2020-04-29 12:20 ` Ronald Natalie
2020-04-29 13:55 Paul Ruizendaal
2020-04-29 14:18 ` ron
2020-04-30 21:49 ` Alexander Voropay
2020-04-30 22:06 ` Clem Cole
2020-04-30 22:09 ` Clem Cole
2020-05-01 0:12 ` Ronald Natalie
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