On Tue, Oct 18, 2022 at 12:47 PM Ulrich Mueller wrote:
>
> > On Tue, 18 Oct 2022, David Seifert wrote:
>
> > What if I want to build Gentoo on an old AMD Thunderbird which has
> > neither SSE1 nor the more important SSE2?
>
> The -mfpmath=sse option is a no-op if the CPU doesn't support SSE,
> On Tue, 18 Oct 2022, David Seifert wrote:
> What if I want to build Gentoo on an old AMD Thunderbird which has
> neither SSE1 nor the more important SSE2?
The -mfpmath=sse option is a no-op if the CPU doesn't support SSE,
i.e. it will use 387 arithmetics nevertheless.
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On Tue, Oct 18, 2022 at 5:56 AM David Seifert wrote:
>
> On Tue, 2022-10-18 at 10:14 +0200, Ulrich Mueller wrote:
> > > > > > > On Tue, 18 Oct 2022, Mike Gilbert wrote:
> >
> > > Reference: https://gcc.gnu.org/wiki/x87note
> >
> > Which says:
> >
> > > ... the amount of worst-case error that
On Tue, Oct 18, 2022 at 9:37 AM David Seifert wrote:
>
> On Tue, 2022-10-18 at 13:40 +0200, Ulrich Mueller wrote:
> > > > > > > On Tue, 18 Oct 2022, David Seifert wrote:
> >
> > > > > -CFLAGS_x86="-m32"
> > > > > +CFLAGS_x86="-m32 -mfpmath=sse"
> >
> > > -mfpmath=sse is already the default on
On Tue, 2022-10-18 at 13:40 +0200, Ulrich Mueller wrote:
> > > > > > On Tue, 18 Oct 2022, David Seifert wrote:
>
> > > > -CFLAGS_x86="-m32"
> > > > +CFLAGS_x86="-m32 -mfpmath=sse"
>
> > -mfpmath=sse is already the default on amd64.
>
> I see. This change makes sense then.
>
> What about
> On Tue, 18 Oct 2022, David Seifert wrote:
>> > -CFLAGS_x86="-m32"
>> > +CFLAGS_x86="-m32 -mfpmath=sse"
> -mfpmath=sse is already the default on amd64.
I see. This change makes sense then.
What about profiles/arch/x86 though? IIUC we'll end up with an
inconsistency between x86 and
On Tue, 2022-10-18 at 10:14 +0200, Ulrich Mueller wrote:
> > > > > > On Tue, 18 Oct 2022, Mike Gilbert wrote:
>
> > Reference: https://gcc.gnu.org/wiki/x87note
>
> Which says:
>
> > ... the amount of worst-case error that could possibly happen using
> > the x87 (with any amount of intermediate
> On Tue, 18 Oct 2022, Mike Gilbert wrote:
> Reference: https://gcc.gnu.org/wiki/x87note
Which says:
| ... the amount of worst-case error that could possibly happen using
| the x87 (with any amount of intermediate rounding) is at worst the
| same as true 64 or 32 bit arithmetic, and in
