l...@gnu.org (Ludovic Courtès) writes:
> Or maybe that's a Debian patch that enables `-mieee' by default?
Actually yes, there's `debian/patches/alpha-ieee.dpatch', which is why I
didn't observe SIGFPEs on Debian GNU/Linux.
Ludo'.
Ludovic Courtès wrote:
> on alpha*-linux-gnu, `-mieee' is apparently not needed:
>
> --8<---cut here---start->8---
> #include
>
> int
> main (int argc, char *argv[])
> {
> return isnan (NAN);
> }
> --8<---cut here---end---
Hi,
Bruno Haible writes:
>> So people compiling with GCC on this platform should pass `-mieee'
>> (`configure' could add it automatically.)
>
> The gnulib module 'fpieee' adds it automatically.
This module appears to be overzealous: `gl_FP_IEEE' just checks for the
host CPU, but on alpha*-linux
Ludovic Courtès wrote:
> >> Should we conclude that this is a GCC bug?
> >
> > Possibly. And what result do you get with "gcc -mieee" ?
>
> It works (returns 1).
>
> The GCC manual (info "(gcc) DEC Alpha Options") reads this:
>
> `-mieee'
>
> [...]
> This option generates code fully I
Hello,
Bruno Haible writes:
> I meant %08X instead of %04X. DQNAN therefore likely is
> FFF8
> which decomposes into
> sign = 1 (irrelevant for NaNs),
> exponent = 0x7FF (highest possible value)
> mantissa = 0x8
> and this is precisely the common encoding of a qui
Ludovic Courtès wrote:
> > And finally, what's the hexdump of that DQNAN constant?
> >
> > #include
> > #include
> > int main()
> > {
> > printf("%04X%04X\n", DQNAN[1], DQNAN[0]);
> > return 0;
> > }
>
> FFF8
I meant %08X instead of %04X. DQNAN therefore likely is
FF
Hi Bruno,
Bruno Haible writes:
> What's the result when you compile it with cc?
> $ cc foo.c -lm
> $ ./a.out
> $ echo $?
1
That's with "Compaq C V6.5-303 (dtk) on Compaq Tru64 UNIX V5.1B
(Rev. 2650)".
Should we conclude that this is a GCC bug? I'll try with different
versions.
> What'
Ludovic Courtès wrote:
> On `alphaev56-dec-osf5.1b', NaN handling seems to be deeply broken.
> Consider this piece of code:
>
> --8<---cut here---start->8---
> #include
>
> extern unsigned int DQNAN[2];
>
> int
> main (int argc, char *argv[])
> {
> return i
