Date: Sun, 18 Jan 2004 13:56:32 -0800 From: David Schultz <das@FreeBSD.ORG> To: Marcel Moolenaar <marcel@xcllnt.net> Cc: cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/lib/libc/gdtoa Makefile.inc _hdtoa.c src/lib/libc/stdio vfprintf.c Message-ID: <20040118215632.GA56462@VARK.homeunix.com> In-Reply-To: <20040118210356.GA82925@dhcp01.pn.xcllnt.net> References: <200401181032.i0IAWoMh012953@repoman.freebsd.org> <20040118103340.GA44149@VARK.homeunix.com> <20040118210356.GA82925@dhcp01.pn.xcllnt.net>
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On Sun, Jan 18, 2004, Marcel Moolenaar wrote:
> Currently stdtod() is causing a SIGFPE on ia64 for a kernel build.
> This started when obrien@ added the following code to kern.post.mk:
>
> +emu10k1-alsa%diked.h: $S/gnu/dev/sound/pci/emu10k1-alsa.h
> + grep -v '#include' ${.OODATE} | ${CC} -E -D__KERNEL__ -dM - \
> + | awk -F"[ (]" '/define/ \
> + { print "#ifndef " $$2 ; print ; print "#endif" }' \
> + >${.TARGET}
> +.if !exists(${.OBJDIR}/.depend)
> +_kernel-depend: emu10k1-alsa%diked.h
> +.endif
>
> The problem is that awk(1) gets a SIGFPE unconditionally. I haven't
> spent too much time on it yet, but I get the following in the gdb(1):
>
> Program received signal SIGFPE, Arithmetic exception.
> 0x40000000000553d2 in strtod (s00=0x600000000001c02d "e-324",
> se=0x9fffffffffffe6f0) at gdtoa_strtod.c:938
> 938 dval(rv) *= dval(rv0);
I don't think this is strtod's fault. awk crashes for the same
reason the following program gets a SIGFPE:
das@pluto1:~> cat bar.c
int main() {
double d = 4.0083367200179456e-292;
d *= 0x1.0p-106;
}
das@pluto1:~> gcc bar.c
das@pluto1:~> ./a.out
Floating exception (core dumped)
The correct result is 4.940656e-324, which is denormalized. Some
architectures generate a trap for denormals and expect them to be
handled in software, but I didn't think that IA64 was one of them.
I'm looking over the IA64 architecture manual now to see if I can
figure out what's going on...
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