| 1 |
On Mon, 2 Oct 2006 07:36:41 +0200 |
| 2 |
Bo Ørsted Andresen <bo.andresen@××××.dk> wrote: |
| 3 |
|
| 4 |
> On Monday 02 October 2006 07:30, Bo Ørsted Andresen wrote: |
| 5 |
> > > Why would flags like mmx, mmxext, sse, and sse2 be masked from mplayer |
| 6 |
> > > for me? |
| 7 |
> > > |
| 8 |
> > > /etc/make.profile -> |
| 9 |
> > > /usr/portage/profiles/default-linux/amd64/2006.1/desktop |
| 10 |
> > |
| 11 |
> > I'm not sure why the use flags are masked. |
| 12 |
> |
| 13 |
> Heh, and then I found it... |
| 14 |
> |
| 15 |
> http://bugs.gentoo.org/show_bug.cgi?id=104674 |
| 16 |
> |
| 17 |
|
| 18 |
Several days ago the guys at gentoo-am64 mailing list explained to me |
| 19 |
all these flags enable different CFLAGS optimizations which came as the |
| 20 |
x86 architecture evolved during the years. When using amd64 the CFLAG |
| 21 |
"-march amd64" enables all architecture specific functions in gcc. |
| 22 |
Simply gcc knows this CPU supports these instuction sets. Further AMD64 |
| 23 |
provides sse2 and the latest CPU models even sse3 which are superior to |
| 24 |
mmx, 3dnow and the other flags mentioned in this thread. So there is |
| 25 |
nothing wrong if these are hard disabled - gcc will take advantage of |
| 26 |
the amd64 arch. without these flags beeng enabled. |
| 27 |
Also I found this official article in the amd64 project site: |
| 28 |
http://www.gentoo.org/doc/en/gentoo-amd64-faq.xml#cflags |
| 29 |
|
| 30 |
"Warning: You should never place -fPIC, -m32 or -m64 in your CFLAGS. |
| 31 |
They are automatically added whenever they are needed. Please also note |
| 32 |
that the -Os flag is currently not supported." |
| 33 |
|
| 34 |
|
| 35 |
There is also another article which explains why these are hard-masked: |
| 36 |
|
| 37 |
http://dev.gentoo.org/~plasmaroo/devmanual/archs/amd64/ |
| 38 |
|
| 39 |
|
| 40 |
|
| 41 |
HTH |
| 42 |
|
| 43 |
-- |
| 44 |
Best regards, |
| 45 |
Daniel |
| 46 |
|
| 47 |
|
| 48 |
-- |
| 49 |
gentoo-user@g.o mailing list |
Archives