CFLAGS on Alpha ev67

[Lupin_the_3rd]

What is the -mev6 flag and is it really needed if you specify -mcpu=ev67

Also, some packages like freeglut complain about the lack of a -march flag. Is there an appropriate one to use for alpha ev67?

TIA!!

[Dottout]

Code: Select all

CHOST="alpha-unknown-linux-gnu"
CFLAGS="-mieee -mcpu=ev67 -Wa,-mev6 -O2 -pipe "
CXXFLAGS="${CFLAGS}"

from gentoo safe cflags wiki

[Lupin_the_3rd]

Am I missing something? Neither your reply, nor that web page say what those flags do. The web page simply lists them as acceptable for this platform. I'm wanting to know what their purpose is. I'm not using the "-Wa,-mev6" flags and my system works perfectly fine.

Edit: when I do add those flags in, things stop compiling. Guess it doesn't matter what they do since they don't work,

[widan]

I'm wanting to know what their purpose is

The "-Wa,-mev6" just tells gcc to pass the "-mev6" flag to the assembler. The "-mev6" assembler flag tells the assembler it can use EV6-specific instructions. I didn't find a "-mev6" gcc flag (at least in "info gcc" - maybe it's an old flag that's translated internally into a newer one).

The "-mieee" flag tells gcc you want IEEE-compliant floating point numbers (it seems Alpha CPUs do not have a fully compliant FPU, so they need some software help for specific cases). There is a paragraph about that in "info gcc".

[Lupin_the_3rd]

Perfect, thanks!