From: Charles Forsyth <charles.forsyth@gmail.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] startboot signature
Date: Thu, 18 Feb 2016 12:28:45 +0000 [thread overview]
Message-ID: <CAOw7k5iTf5y3qv5BDx6C_LVC1vOurqvDQkhs+Vcc-LFyVR2pBA@mail.gmail.com> (raw)
In-Reply-To: <CAHL7psFYf3ApZtkpn7vwVGzDfkKC1fMpJzwQ8_G=YFWHPD7j7Q@mail.gmail.com>
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On 17 February 2016 at 08:19, Giacomo Tesio <giacomo@tesio.it> wrote:
> Out of curiosity, why the startboot function in port/initcode.c is `void
> startboot(char *argv0, char **argv)` given the argv0 is ignored?
>
> I see that this simplify various main() in init9.s but I wonder why not
> simply use `void startboot(char **argv)`
>
There's possibly some historic reason for having argv0 instead of argc (ie,
possibly a time when argv0 was used),
but it also makes things a little easier on platforms (all but 386) where
the first parameter is passed in a register.
Since the setup code is machine dependent, it could get that right by
setting r0, r3 or bp in the saved Ureg,
but it probably isn't worthwhile changing all that now.
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prev parent reply other threads:[~2016-02-18 12:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 8:19 Giacomo Tesio
2016-02-18 12:28 ` Charles Forsyth [this message]
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