On Fri, Mar 15, 2002 at 12:10:25 -0500, Charles Shannon Hendrix wrote:

> > : In any case, the library extension you mention will not speed up the code
> > : outside of the libraries.
> > 
> > Huh!?  Having an overlay listed in ld.so.conf will affect *all* code
> > (program or library) using the (shared) libc, without recompiling.
> 
> All you have done here is reaffirm what I said above: this change
> affects code *in libraries*, not outside of them.

You don't understand.  See page 236 of Sparc V8 manual.  Without -mv8
all code is generated to call (e.g.) ".umul" function from a shared
library (libc) to perform multiplication (for v8 an "umul" instruction
would be generated).  So with the overlay *all* dynamically linked
programs will call v8'ified ".umul" that just calls real "umul"
instruction, instead of doing a bunch of "mulscc".

IOW, on a real v8 the code compiled without -mv8 but being run with
the overlay will be something like:

    ...
    call .umul
    ...

!! this comes from the overlay
.umul:
    retl
     umul ...

instead of just

    umul ...

that -mv8 would generate.

SY, Uwe
-- 
uwe@ptc.spbu.ru                         |       Zu Grunde kommen
http://www.ptc.spbu.ru/~uwe/            |       Ist zu Grunde gehen