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Date: Tue, 6 Dec 2011 11:44:00 +0100
From: Gary Jennejohn <gljennjohn@googlemail.com>
To: some body <bsd.mharv@gmail.com>
Message-ID: <20111206114400.6dbea313@ernst.jennejohn.org>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: boot0.S empty #ifdef
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On Mon, 5 Dec 2011 12:54:15 -0800
some body <bsd.mharv@gmail.com> wrote:

> I sent this to freebsd-drives too but I think that might not be the right
> list for it so here it is: I am starting to learn how the kernel works and
> have started by going through the boot loader and I've noticed that between
> lines 21-32 in boot0.S there are some empty #ifdef statements. I was
> wondering a) where are these paramaters defined and if they are defined,
> what difference does it make since it looks like it doesn't change anything
> since they're empty?
> 
> 
> #ifdef SIO
> #endif
> 
> #ifdef CHECK_DRIVE
> #endif
> 
> #ifdef ONLY_F_KEYS
> #endif
>

These seem to be there to act as reminders for command line options which
can be used to build boot0.  They're also documented in Makefile.

These are actually used later in the code.

-- 
Gary Jennejohn