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Soft-Float emulation with gcc - pr3900

To: linux-mips@fnet.fr, linux-mips@oss.sgi.com
Subject: Soft-Float emulation with gcc - pr3900
From: Zoon <zoon974@yahoo.com>
Date: Thu, 16 Aug 2001 09:04:04 +0100 (BST)
In-reply-to: <Pine.GSO.3.96.1010814193527.5426C-100000@delta.ds2.pg.gda.pl>
Hello, 

Although this message is more about gcc, I post here,
since I got no answer from gcc mailing lists.

I use egcs-2.91.66(Algorithmics tools) configured as a
cross-compiler on a i386 host. I got the binary
version, so didn't configured it myself.

I'm working with a PR3900 type MIPS core. Those core
don't have a Floating Point Unit, nor floating point
registers.
When using -msoft-float, I am supposed to use the
libgcc soft floating point emulation. However, I
cannot prevent gcc from using fp registers.
When looking at gcc specs:

$ mips-linux-gcc -dumpspecs | grep r3900
..
%{m3900:-mips1 -mcpu=r3900 -mfp32 -mgp32}...

The option -mfp32 is defined as the default, which
means gcc assume 32 bit fp registers are available.

I am aware of two soft-float emulation libraries:
Gofast and libgcc. However I can't figure out how
emulation can be achieved if gcc keeps using fp
registers. 

I must miss something about it, could someone help me
with this matter ?

Many thanks,
Alain

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