Subject: Re: Monta Vista Linux Supporting Floating Point operations

From: Mark Hatle <[email-masked]>
Date: Wed, 23 Oct 2002 08:28:35 -0500

Vishwanath wrote:
> Hi All,
>
> I am working on 440GP using Monta Vista Linux 2.1. I need floating point
> operation support (for eg. function sqrt() for calculating square root of
> given float variable) on Linux. I didn't find math emualtion on the Linux.
> Can anyone tell me how can I get floating point support ?

Floating point support in MontaVista Linux is handled by the compiler and _NOT_
the kernel.  In architecting our system we have weighed the tradeoffs between
soft-floating point, or hard-floating point using kernel exceptions.
Soft-floating point was found to be superior so we use it on all platforms
without a hardware FPU.

One thing to note, because of this the ABI is slightly different then the
binaries you would download off of a random community website.  You need to use
our compiler (or a community compiler configured appropriatly) to build
soft-float.  (On a non-MontaVista compiler, you usually need to pass
-msoft-float on the command line to gcc.)

--Mark

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