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Re: MIPS SF toolchain

To: Matej Kupljen <matej.kupljen@ultra.si>
Subject: Re: MIPS SF toolchain
From: David Daney <ddaney@avtrex.com>
Date: Fri, 09 Sep 2005 08:20:03 -0700
Cc: crossgcc@sources.redhat.com, linux-mips@linux-mips.org
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Matej Kupljen wrote:
Hi


Can I just #ifdef this code if compiled for sf?


I do have some patches for glibc to get rid of these in a soft float build.


Can I see these patches, please?
(What is the #define for the FP?)


However as Ralf Baechle said in the other message, the kernel FP emulator works and is not that large of an overhead.


Attached is the portions of my patches to glibc-2.3.3 that contain the setjump/longjump hacks. There are other things in there as well, so you will have to pick and choose as to which parts you want.

I did this more as a proof of concept rather than the definitive answer. There are still some FP instructions being generated but I have not tracked them down yet.

On my 2.4.29 based kernel (mipsel-linux) with glibc 2.3.3 and busybox 1.00, I don't get the 'Algorithmics/MIPS FPU Emulator v1.5' message until I run ldconfig or ftp. Most other programs don't seem to run any FP instructions.


I also removed the FP Emulator in the kernel, just to be sure that
no SF ins are executed (I can send the patch to the list, but I know
there has already been discussion about this).

IMHO, if we say that we have a SF toolchain then there MUST NOT
BE any SF ins, otherwise we have a "semi soft float" toolchain.
Don't you agree?

Of course I agree.

David Daney.

Attachment: glibc-2.3.3.diff.gz
Description: GNU Zip compressed data

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