Re: (Hardware?) problem with denormal values on mipsel
Hi,
On Tue, May 26, 2015 at 10:13:35AM +0100, James Cowgill wrote:
> On Sun, 2015-05-24 at 22:32 +0300, Aaro Koskinen wrote:
> > On Fri, May 22, 2015 at 11:00:18PM +0100, James Cowgill wrote:
> > > On Sat, 2015-05-23 at 00:04 +0300, Aaro Koskinen wrote:
> > > > On Fri, May 22, 2015 at 05:27:14PM +0100, James Cowgill wrote:
> > > > > Yep it's a hardware problem. The following assembly dies (raises SIGILL)
> > > > > at 'sqrt.s' on the Loongsons and works everywhere else:
> > > > >
> > > > > ===
> > > > > .set mips2
> > > > > .text
> > > > > .global main
> > > > > .type main, @function
> > > > > main:
> > > > > lui $t0, %hi(value)
> > > > > lwc1 $f0, %lo(value)($t0)
> > > > > nop
> > > > > sqrt.s $f0, $f0
> > > > > jr $ra
> > > > >
> > > > > .data
> > > > > value:
> > > > > .float 1.1342362e-39
> > > > > ===
> > > >
> > > > Is this a standalone reproducer program for the problem? Because
> > > > I tried it on on my Loongson box and didn't get any SIGILL...
> > >
> > > It should be. I tried it on some 3A machines at work and it crashed
> > > there (and then some other machines which didn't crash). There's a 2F I
> > > can try on Tuesday.
> >
> > My Loongson is 2F...
>
> I tried it on my 2F (it's a Lemote Fuloong) and it crashed there as well
> (both the gfortran and my testcase). It's running up to date jessie.
>
> What compiler versions do you have?
> What does the 'cpu model' line say in /proc/cpuinfo?
I'm using binutils 2.25, GCC 5.1, Linux 4.1-rc5. The cpu model is:
cpu model : ICT Loongson-2 V0.3 FPU V0.1
> > > Does the original gfortran code crash for you?
> >
> > I don't have gfortran available on my system.
>
> Don't you run Debian?
Not at the moment.
A.
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