Re: manipulating FPU rounding modes on alpha

[Joachim Reichel <joachim.reichel@gmx.de>]

Hi,

> Build fails running 2.6.22, or rather the test fails.
> 
> Running 'LD_LIBRARY_PATH=/root/cgal-3.3.1/debian/tmp/usr/lib
> /root/cgal-3.3.1/debian/tests/rounding_modes' returns:
> default: ERROR
> get/set: ERROR
> ZERO
> zero   : ERROR
> ZERO
> +inf   : ERROR
> ZERO
> -inf   : ERROR
> ZERO
> near   : ERROR
> ZERO
> 
> But if I then load the 'math_emu' module and repeat the command I get:
> default: ok
> get/set: ok
> zero   : ok
> +inf   : ok
> -inf   : ok
> near   : ok

this is exactly the same result that I get on Uwe's EV56 without and
with math_emu. I'm not in the position to discuss whether math_emu
should be a module or built in.

> I also see an indication that if you call gcc with the -mieee option, it
> will generate code that runs on any alpha correctly, without relying on
> the kernel to solve the problem for it.

Your conclusion seems wrong since the test is built with "-mieee
-mfp-rounding-mode=d -frounding-math".

Note that the failure is slightly different from that in the build logs on ds10
(which is an EV6 anyway). Maybe the problem is specific to EV6 and above?

Is another alpha developer willing to help? I asked Martin Zobel-Helas
for an account on ds10, but he is quite busy right now with listmaster
stuff.

Lennart, thanks for your help.

Regards,
  Joachim

P.S.: Please CC: me on replies.