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Re: RFC: Define __FPMATH_387__ and __FPMATH_SSE__


On 3/2/06, H. J. Lu <hjl@lucon.org> wrote:
> With this patch:
>
> http://gcc.gnu.org/ml/gcc-patches/2004-11/msg01877.html
>
> gcc no longer mixes SSE and x387 math by default. However glibc
> still assumes gcc mixes SSE and x387 math. The x86-64 FP control
> routines in glibc change both SSE and x387 units, which is no
> longer necessary with the newer gcc. But glibc has no way to know
> if gcc mixes SSE and x387 math. I am proposing to define
> __FPMATH_387__ if x387 math is used and define __FPMATH_SSE__ if
> SSE math is used, respectively. If 2 units are used, both will
> be defined. Glibc can have sets math unit control routines and
> only call the ones be using.

Which routines are you referring to?  I can only find
sysdeps/x86_64/fpu_control.h
which only touches x387 unit.  I think it would make sense to add gcc builtins
for status/control word changes, though.

Richard.


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