On Mon, 2 Oct 2006 07:36:41 +0200 Bo Ørsted Andresen <[EMAIL PROTECTED]> wrote:
> On Monday 02 October 2006 07:30, Bo Ørsted Andresen wrote: > > > Why would flags like mmx, mmxext, sse, and sse2 be masked from mplayer > > > for me? > > > > > > /etc/make.profile -> > > > /usr/portage/profiles/default-linux/amd64/2006.1/desktop > > > > I'm not sure why the use flags are masked. > > Heh, and then I found it... > > http://bugs.gentoo.org/show_bug.cgi?id=104674 > Several days ago the guys at gentoo-am64 mailing list explained to me all these flags enable different CFLAGS optimizations which came as the x86 architecture evolved during the years. When using amd64 the CFLAG "-march amd64" enables all architecture specific functions in gcc. Simply gcc knows this CPU supports these instuction sets. Further AMD64 provides sse2 and the latest CPU models even sse3 which are superior to mmx, 3dnow and the other flags mentioned in this thread. So there is nothing wrong if these are hard disabled - gcc will take advantage of the amd64 arch. without these flags beeng enabled. Also I found this official article in the amd64 project site: http://www.gentoo.org/doc/en/gentoo-amd64-faq.xml#cflags "Warning: You should never place -fPIC, -m32 or -m64 in your CFLAGS. They are automatically added whenever they are needed. Please also note that the -Os flag is currently not supported." There is also another article which explains why these are hard-masked: http://dev.gentoo.org/~plasmaroo/devmanual/archs/amd64/ HTH -- Best regards, Daniel -- gentoo-user@gentoo.org mailing list