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Date:      Mon, 03 Mar 2008 19:38:38 +0100
From:      Jean-Yves Moulin <jean-yves.moulin@kewego.com>
To:        freebsd-amd64@freebsd.org
Subject:   Re: kernel module and float
Message-ID:  <47CC45AE.5050703@kewego.com>
In-Reply-To: <20080303181957.GA62714@slackbox.xs4all.nl>
References:  <47CBF364.4030905@kewego.com> <20080303181957.GA62714@slackbox.xs4all.nl>

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Roland Smith wrote:
> Floating point arithmetic isn't used in the kernel for performance
> reasons.[1] The kernel is compiled with -msoft-float which prevents gcc
> from generating floating point instructions. In this case it uses
> routines that are part of libgcc. As far as I can tell, the kernel isn't
> linked with libgcc. 
>   

Of course, kernel isn't linked  :) But why this code can be compiled and 
ran in i386 and not in amd64  ?

When I compile on amd64, using <bsd.kmod.mk>, I have  -mfpmath=387 and 
-msoft-float in my gcc flags. So, I was thinking I could use simple 
floating point operation. This two flags doesn't appear on i386.

Thanks for your reply! I will change my code.

jym



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