Re: [Mesa3d-dev] Re: [Xpert]mesa assuming glibc 2.2? (Cannot compile4.1 on RedHat 6.2)

[Brian P. <br...@va...>]

"Mike A. Harris" wrote:
> 
> On Tue, 5 Jun 2001, Brian Paul wrote:
> 
> >>  Granted, it's not the best solution, but it's at least an useful error.
> >>  Some conditionals on the configuration files would do it, too.
> >>  (HAVE_LINUX_2_4_HEADERS, Imakefile style).  The point is, you need 2.4
> >>  kernel headers to compile this.
> >
> >
> >I'd like to see a solution that doesn't interupt compilation.  That
> >is, if we can't use SSE at compile time, it should just be disabled,
> >perhaps with a warning.
> 
> Then in order to use SSE on a machine at runtime, one must have
> an SSE capable machine to build on?  I don't like the sound of
> that, even if my box has SSE.  IMHO, the build host should be
> independant of the runtime host.
> 
> Perhaps I am misunderstanding the above comments?

Perhaps so.  At runtime, the Mesa code tries to execute some SSE
instructions and checks if it works or not.  It might fail because
there's no kernel support or you're using a CPU without SSE
instructions.  This is done with an exception handler.

Now at compile time we need at least a certain version of the system
headers in order to compile the exception handler code.
If we don't have the right headers, we can't compile the code.  I'm
just saying that I'd rather the compilation continued without SSE
capability rather than bomb out.

If you've got the right headers but compiling on a non-SSE CPU you
can certainly compile in the SSE support.  You just won't be able to
use it on that system.

-Brian