Re: [Qemu-devel] [sparc] Floating point exception issue
On Sat, Jan 22, 2011 at 5:45 PM, Robert Reif wrote:
> Blue Swirl wrote:
>>
>> On Sat, Jan 22, 2011 at 3:30 PM, Mateusz Loskot
>> wrote:
>>
>>>
>>> On 18/01/11 21:51, Blue Swirl wrote:
>>>
On Tue, Jan 18, 2011 at 6:00 PM, Mateusz Loskot
wrote:
>
> On 18/01/11 17:36, Blue Swirl wrote:
>
>>
>> On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot
>> wrote:
>>
>>>
>>> Hi,
>>>
>>> Recently, I have reported mysterious issues on NetBSD 5.1
>>> emulated on SPARC. The whole first thread is here:
>>>
>>> http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
>>>
>>> I decided to investigate the problem deeper and with great help
>>> from NetBSD folks, I managed to find reproducible test case.
>>> Initially, it was AWK command:
>>>
>>> # echo NaN | awk '{print "test"}'
>>> awk: floating point exception 8
>>> source line number 1
>>>
>>> and next it boiled down to simple C program (see below).
>>> Details of the investigation are archived in the NetBSD Problem
>>> Report #44389 here:
>>>
>>> http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
>>>
>>>
>>> Here is final version of the test program which reproduces the
>>> problem:
>>>
>>> #include
>>> #include
>>> #include
>>> #include
>>>
>>> int is_number(const char *s)
>>> {
>>> double r;
>>> char *ep;
>>> errno = 0;
>>> r = strtod(s,&ep);
>>> if (r == HUGE_VAL)
>>> printf("X:%g\n", r);
>>>
>>> if (ep == s || r == HUGE_VAL || errno == ERANGE)
>>> return 0;
>>> while (*ep == ' ' || *ep == '\t' || *ep == '\n')
>>> ep++;
>>> if (*ep == '\0')
>>> return 1;
>>> else
>>> return 0;
>>> }
>>>
>>> int main(int argc, char **argv)
>>> {
>>> double v;
>>>
>>> if (is_number("NaN")) {
>>> printf("is a number\n");
>>> v = atof("NaN");
>>> } else {
>>> printf("not a number\n");
>>> v = 0.0;
>>> }
>>> printf("%.4f\n", v);
>>>
>>> return 0;
>>> }
>>>
>>>
>>> On NetBSD/SPARC, the program receives SIGFPE:
>>>
>>> $ gcc ./nan_test_2.c
>>> $ ./a.out
>>> [1] Floating point exception (core dumped) ./a.out
>>>
>>> Specifically, it's caused by r == HUGE_VAL condition in
>>> if (ep == s || r == HUGE_VAL || errno == ERANGE)
>>> where r is NaN.
>>>
>>> All the signs indicate there is a bug in QEMU.
>>>
>>
>> I'll install 5.1, but on 4.0 which I had installed, the program works
>> fine:
>> $ ./sigfpe
>> is a number
>> nan
>>
>
> I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use
> with
> NetBSD 5.1/SPARC) and it works well indeed:
>
> mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
> is a number
> nan
> mloskot@qemu-netbsd-50-sparc:~/tmp#
>
> Hmm, this is becoming interesting.
>
> I run QEMU 0.13 on Windows Vista (64-bit).
> Perhaps host system and QEMU binaries are relevant here.
> I will try on Linux host system later tonight.
>
> BTW, here are my images:
>
> http://mateusz.loskot.net/tmp/qemu/
>
The problem was with NaN handling in fcmped instruction. I've
committed a patch that fixes the problem, please test. Thanks for
reporting and the test case.
>>>
>>> FYI, this problem seems to be occurring in qemu on Windows only.
>>> I tested git version dated before you applied the fix
>>> and built on Linux and the problem does not happening there.
>>>
>>
>> No, it was generic problem. I could reproduce it with your test case
>> and with a small assembler program which only used fcmped using user
>> emulator.
>>
>>
>>
>
> There is still a floating point exception problem that may or may not be
> related.
AFAICS they are not related. Strictly speaking they are not FP
problems but deferred trap processing problems.
> Booting an ss5-170 with a real sun ROM image still fails FP tests:
>
> 4.1.1 fpu reg regfile Pass
> 4.1.2 fpu reg misalign Pass
> 4.1.3 fpu reg single precision Pass
> 4.1.4 fpu reg double precision Pass
> 4.2.1 fpu exceptions single precision Failed
> Exception Didn't Block Store : 0 : exp= , obs=
> 4.2.2 fpu exceptions double precision Failed
> Exception Didn't Block Store : 0 : exp= , obs=
>
>
>
--
Regards,
Artyom Tarasenko
solaris/sparc under qemu blog: http://tyom.blogspot.com/
Re: [Qemu-devel] [sparc] Floating point exception issue
Blue Swirl wrote:
On Sat, Jan 22, 2011 at 3:30 PM, Mateusz Loskot wrote:
On 18/01/11 21:51, Blue Swirl wrote:
On Tue, Jan 18, 2011 at 6:00 PM, Mateusz Loskot wrote:
On 18/01/11 17:36, Blue Swirl wrote:
On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot
wrote:
Hi,
Recently, I have reported mysterious issues on NetBSD 5.1
emulated on SPARC. The whole first thread is here:
http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
I decided to investigate the problem deeper and with great help
from NetBSD folks, I managed to find reproducible test case.
Initially, it was AWK command:
# echo NaN | awk '{print "test"}'
awk: floating point exception 8
source line number 1
and next it boiled down to simple C program (see below).
Details of the investigation are archived in the NetBSD Problem
Report #44389 here:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
Here is final version of the test program which reproduces the problem:
#include
#include
#include
#include
int is_number(const char *s)
{
double r;
char *ep;
errno = 0;
r = strtod(s,&ep);
if (r == HUGE_VAL)
printf("X:%g\n", r);
if (ep == s || r == HUGE_VAL || errno == ERANGE)
return 0;
while (*ep == ' ' || *ep == '\t' || *ep == '\n')
ep++;
if (*ep == '\0')
return 1;
else
return 0;
}
int main(int argc, char **argv)
{
double v;
if (is_number("NaN")) {
printf("is a number\n");
v = atof("NaN");
} else {
printf("not a number\n");
v = 0.0;
}
printf("%.4f\n", v);
return 0;
}
On NetBSD/SPARC, the program receives SIGFPE:
$ gcc ./nan_test_2.c
$ ./a.out
[1] Floating point exception (core dumped) ./a.out
Specifically, it's caused by r == HUGE_VAL condition in
if (ep == s || r == HUGE_VAL || errno == ERANGE)
where r is NaN.
All the signs indicate there is a bug in QEMU.
I'll install 5.1, but on 4.0 which I had installed, the program works
fine:
$ ./sigfpe
is a number
nan
I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use with
NetBSD 5.1/SPARC) and it works well indeed:
mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
is a number
nan
mloskot@qemu-netbsd-50-sparc:~/tmp#
Hmm, this is becoming interesting.
I run QEMU 0.13 on Windows Vista (64-bit).
Perhaps host system and QEMU binaries are relevant here.
I will try on Linux host system later tonight.
BTW, here are my images:
http://mateusz.loskot.net/tmp/qemu/
The problem was with NaN handling in fcmped instruction. I've
committed a patch that fixes the problem, please test. Thanks for
reporting and the test case.
FYI, this problem seems to be occurring in qemu on Windows only.
I tested git version dated before you applied the fix
and built on Linux and the problem does not happening there.
No, it was generic problem. I could reproduce it with your test case
and with a small assembler program which only used fcmped using user
emulator.
There is still a floating point exception problem that may or may not be
related.
Booting an ss5-170 with a real sun ROM image still fails FP tests:
4.1.1 fpureg regfile Pass
4.1.2 fpureg misalign Pass
4.1.3 fpureg single precision Pass
4.1.4 fpureg double precision Pass
4.2.1 fpuexceptions single precision Failed
Exception Didn't Block Store : 0 : exp= , obs=
4.2.2 fpuexceptions double precision Failed
Exception Didn't Block Store : 0 : exp= , obs=
Re: [Qemu-devel] [sparc] Floating point exception issue
On Sat, Jan 22, 2011 at 3:30 PM, Mateusz Loskot wrote:
> On 18/01/11 21:51, Blue Swirl wrote:
>> On Tue, Jan 18, 2011 at 6:00 PM, Mateusz Loskot wrote:
>>> On 18/01/11 17:36, Blue Swirl wrote:
On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot
wrote:
>
> Hi,
>
> Recently, I have reported mysterious issues on NetBSD 5.1
> emulated on SPARC. The whole first thread is here:
>
> http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
>
> I decided to investigate the problem deeper and with great help
> from NetBSD folks, I managed to find reproducible test case.
> Initially, it was AWK command:
>
> # echo NaN | awk '{print "test"}'
> awk: floating point exception 8
> source line number 1
>
> and next it boiled down to simple C program (see below).
> Details of the investigation are archived in the NetBSD Problem
> Report #44389 here:
>
> http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
>
>
> Here is final version of the test program which reproduces the problem:
>
> #include
> #include
> #include
> #include
>
> int is_number(const char *s)
> {
> double r;
> char *ep;
> errno = 0;
> r = strtod(s,&ep);
> if (r == HUGE_VAL)
> printf("X:%g\n", r);
>
> if (ep == s || r == HUGE_VAL || errno == ERANGE)
> return 0;
> while (*ep == ' ' || *ep == '\t' || *ep == '\n')
> ep++;
> if (*ep == '\0')
> return 1;
> else
> return 0;
> }
>
> int main(int argc, char **argv)
> {
> double v;
>
> if (is_number("NaN")) {
> printf("is a number\n");
> v = atof("NaN");
> } else {
> printf("not a number\n");
> v = 0.0;
> }
> printf("%.4f\n", v);
>
> return 0;
> }
>
>
> On NetBSD/SPARC, the program receives SIGFPE:
>
> $ gcc ./nan_test_2.c
> $ ./a.out
> [1] Floating point exception (core dumped) ./a.out
>
> Specifically, it's caused by r == HUGE_VAL condition in
> if (ep == s || r == HUGE_VAL || errno == ERANGE)
> where r is NaN.
>
> All the signs indicate there is a bug in QEMU.
I'll install 5.1, but on 4.0 which I had installed, the program works
fine:
$ ./sigfpe
is a number
nan
>>>
>>> I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use with
>>> NetBSD 5.1/SPARC) and it works well indeed:
>>>
>>> mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
>>> is a number
>>> nan
>>> mloskot@qemu-netbsd-50-sparc:~/tmp#
>>>
>>> Hmm, this is becoming interesting.
>>>
>>> I run QEMU 0.13 on Windows Vista (64-bit).
>>> Perhaps host system and QEMU binaries are relevant here.
>>> I will try on Linux host system later tonight.
>>>
>>> BTW, here are my images:
>>>
>>> http://mateusz.loskot.net/tmp/qemu/
>>
>> The problem was with NaN handling in fcmped instruction. I've
>> committed a patch that fixes the problem, please test. Thanks for
>> reporting and the test case.
>
> FYI, this problem seems to be occurring in qemu on Windows only.
> I tested git version dated before you applied the fix
> and built on Linux and the problem does not happening there.
No, it was generic problem. I could reproduce it with your test case
and with a small assembler program which only used fcmped using user
emulator.
Re: [Qemu-devel] [sparc] Floating point exception issue
On 18/01/11 21:51, Blue Swirl wrote:
> On Tue, Jan 18, 2011 at 6:00 PM, Mateusz Loskot wrote:
>> On 18/01/11 17:36, Blue Swirl wrote:
>>>
>>> On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot
>>> wrote:
Hi,
Recently, I have reported mysterious issues on NetBSD 5.1
emulated on SPARC. The whole first thread is here:
http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
I decided to investigate the problem deeper and with great help
from NetBSD folks, I managed to find reproducible test case.
Initially, it was AWK command:
# echo NaN | awk '{print "test"}'
awk: floating point exception 8
source line number 1
and next it boiled down to simple C program (see below).
Details of the investigation are archived in the NetBSD Problem
Report #44389 here:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
Here is final version of the test program which reproduces the problem:
#include
#include
#include
#include
int is_number(const char *s)
{
double r;
char *ep;
errno = 0;
r = strtod(s,&ep);
if (r == HUGE_VAL)
printf("X:%g\n", r);
if (ep == s || r == HUGE_VAL || errno == ERANGE)
return 0;
while (*ep == ' ' || *ep == '\t' || *ep == '\n')
ep++;
if (*ep == '\0')
return 1;
else
return 0;
}
int main(int argc, char **argv)
{
double v;
if (is_number("NaN")) {
printf("is a number\n");
v = atof("NaN");
} else {
printf("not a number\n");
v = 0.0;
}
printf("%.4f\n", v);
return 0;
}
On NetBSD/SPARC, the program receives SIGFPE:
$ gcc ./nan_test_2.c
$ ./a.out
[1] Floating point exception (core dumped) ./a.out
Specifically, it's caused by r == HUGE_VAL condition in
if (ep == s || r == HUGE_VAL || errno == ERANGE)
where r is NaN.
All the signs indicate there is a bug in QEMU.
>>>
>>> I'll install 5.1, but on 4.0 which I had installed, the program works
>>> fine:
>>> $ ./sigfpe
>>> is a number
>>> nan
>>
>> I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use with
>> NetBSD 5.1/SPARC) and it works well indeed:
>>
>> mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
>> is a number
>> nan
>> mloskot@qemu-netbsd-50-sparc:~/tmp#
>>
>> Hmm, this is becoming interesting.
>>
>> I run QEMU 0.13 on Windows Vista (64-bit).
>> Perhaps host system and QEMU binaries are relevant here.
>> I will try on Linux host system later tonight.
>>
>> BTW, here are my images:
>>
>> http://mateusz.loskot.net/tmp/qemu/
>
> The problem was with NaN handling in fcmped instruction. I've
> committed a patch that fixes the problem, please test. Thanks for
> reporting and the test case.
FYI, this problem seems to be occurring in qemu on Windows only.
I tested git version dated before you applied the fix
and built on Linux and the problem does not happening there.
Best regards,
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
Member of ACCU, http://accu.org
Re: [Qemu-devel] [sparc] Floating point exception issue
On 18/01/11 21:51, Blue Swirl wrote:
On Tue, Jan 18, 2011 at 6:00 PM, Mateusz Loskot wrote:
On 18/01/11 17:36, Blue Swirl wrote:
On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot
wrote:
Hi,
Recently, I have reported mysterious issues on NetBSD 5.1
emulated on SPARC. The whole first thread is here:
http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
I decided to investigate the problem deeper and with great help
from NetBSD folks, I managed to find reproducible test case.
Initially, it was AWK command:
# echo NaN | awk '{print "test"}'
awk: floating point exception 8
source line number 1
and next it boiled down to simple C program (see below).
Details of the investigation are archived in the NetBSD Problem
Report #44389 here:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
Here is final version of the test program which reproduces the problem:
#include
#include
#include
#include
int is_number(const char *s)
{
double r;
char *ep;
errno = 0;
r = strtod(s,&ep);
if (r == HUGE_VAL)
printf("X:%g\n", r);
if (ep == s || r == HUGE_VAL || errno == ERANGE)
return 0;
while (*ep == ' ' || *ep == '\t' || *ep == '\n')
ep++;
if (*ep == '\0')
return 1;
else
return 0;
}
int main(int argc, char **argv)
{
double v;
if (is_number("NaN")) {
printf("is a number\n");
v = atof("NaN");
} else {
printf("not a number\n");
v = 0.0;
}
printf("%.4f\n", v);
return 0;
}
On NetBSD/SPARC, the program receives SIGFPE:
$ gcc ./nan_test_2.c
$ ./a.out
[1] Floating point exception (core dumped) ./a.out
Specifically, it's caused by r == HUGE_VAL condition in
if (ep == s || r == HUGE_VAL || errno == ERANGE)
where r is NaN.
All the signs indicate there is a bug in QEMU.
I'll install 5.1, but on 4.0 which I had installed, the program works
fine:
$ ./sigfpe
is a number
nan
I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use with
NetBSD 5.1/SPARC) and it works well indeed:
mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
is a number
nan
mloskot@qemu-netbsd-50-sparc:~/tmp#
Hmm, this is becoming interesting.
I run QEMU 0.13 on Windows Vista (64-bit).
Perhaps host system and QEMU binaries are relevant here.
I will try on Linux host system later tonight.
BTW, here are my images:
http://mateusz.loskot.net/tmp/qemu/
The problem was with NaN handling in fcmped instruction. I've
committed a patch that fixes the problem, please test.
I'm having problems with building qemu under MinGW, so I will need to
wait for someone to update binaries.
Stefan, are you planning to update your binaries?
I would be grateful.
Thanks for reporting and the test case.
Thanks for fixing!
Best regards,
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
Member of ACCU, http://accu.org
Re: [Qemu-devel] [sparc] Floating point exception issue
On Tue, Jan 18, 2011 at 6:00 PM, Mateusz Loskot wrote:
> On 18/01/11 17:36, Blue Swirl wrote:
>>
>> On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot
>> wrote:
>>>
>>> Hi,
>>>
>>> Recently, I have reported mysterious issues on NetBSD 5.1
>>> emulated on SPARC. The whole first thread is here:
>>>
>>> http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
>>>
>>> I decided to investigate the problem deeper and with great help
>>> from NetBSD folks, I managed to find reproducible test case.
>>> Initially, it was AWK command:
>>>
>>> # echo NaN | awk '{print "test"}'
>>> awk: floating point exception 8
>>> source line number 1
>>>
>>> and next it boiled down to simple C program (see below).
>>> Details of the investigation are archived in the NetBSD Problem
>>> Report #44389 here:
>>>
>>> http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
>>>
>>>
>>> Here is final version of the test program which reproduces the problem:
>>>
>>> #include
>>> #include
>>> #include
>>> #include
>>>
>>> int is_number(const char *s)
>>> {
>>> double r;
>>> char *ep;
>>> errno = 0;
>>> r = strtod(s,&ep);
>>> if (r == HUGE_VAL)
>>> printf("X:%g\n", r);
>>>
>>> if (ep == s || r == HUGE_VAL || errno == ERANGE)
>>> return 0;
>>> while (*ep == ' ' || *ep == '\t' || *ep == '\n')
>>> ep++;
>>> if (*ep == '\0')
>>> return 1;
>>> else
>>> return 0;
>>> }
>>>
>>> int main(int argc, char **argv)
>>> {
>>> double v;
>>>
>>> if (is_number("NaN")) {
>>> printf("is a number\n");
>>> v = atof("NaN");
>>> } else {
>>> printf("not a number\n");
>>> v = 0.0;
>>> }
>>> printf("%.4f\n", v);
>>>
>>> return 0;
>>> }
>>>
>>>
>>> On NetBSD/SPARC, the program receives SIGFPE:
>>>
>>> $ gcc ./nan_test_2.c
>>> $ ./a.out
>>> [1] Floating point exception (core dumped) ./a.out
>>>
>>> Specifically, it's caused by r == HUGE_VAL condition in
>>> if (ep == s || r == HUGE_VAL || errno == ERANGE)
>>> where r is NaN.
>>>
>>> All the signs indicate there is a bug in QEMU.
>>
>> I'll install 5.1, but on 4.0 which I had installed, the program works
>> fine:
>> $ ./sigfpe
>> is a number
>> nan
>
> I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use with
> NetBSD 5.1/SPARC) and it works well indeed:
>
> mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
> is a number
> nan
> mloskot@qemu-netbsd-50-sparc:~/tmp#
>
> Hmm, this is becoming interesting.
>
> I run QEMU 0.13 on Windows Vista (64-bit).
> Perhaps host system and QEMU binaries are relevant here.
> I will try on Linux host system later tonight.
>
> BTW, here are my images:
>
> http://mateusz.loskot.net/tmp/qemu/
The problem was with NaN handling in fcmped instruction. I've
committed a patch that fixes the problem, please test. Thanks for
reporting and the test case.
Re: [Qemu-devel] [sparc] Floating point exception issue
On 18/01/11 17:36, Blue Swirl wrote:
On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot wrote:
Hi,
Recently, I have reported mysterious issues on NetBSD 5.1
emulated on SPARC. The whole first thread is here:
http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
I decided to investigate the problem deeper and with great help
from NetBSD folks, I managed to find reproducible test case.
Initially, it was AWK command:
# echo NaN | awk '{print "test"}'
awk: floating point exception 8
source line number 1
and next it boiled down to simple C program (see below).
Details of the investigation are archived in the NetBSD Problem
Report #44389 here:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
Here is final version of the test program which reproduces the problem:
#include
#include
#include
#include
int is_number(const char *s)
{
double r;
char *ep;
errno = 0;
r = strtod(s,&ep);
if (r == HUGE_VAL)
printf("X:%g\n", r);
if (ep == s || r == HUGE_VAL || errno == ERANGE)
return 0;
while (*ep == ' ' || *ep == '\t' || *ep == '\n')
ep++;
if (*ep == '\0')
return 1;
else
return 0;
}
int main(int argc, char **argv)
{
double v;
if (is_number("NaN")) {
printf("is a number\n");
v = atof("NaN");
} else {
printf("not a number\n");
v = 0.0;
}
printf("%.4f\n", v);
return 0;
}
On NetBSD/SPARC, the program receives SIGFPE:
$ gcc ./nan_test_2.c
$ ./a.out
[1] Floating point exception (core dumped) ./a.out
Specifically, it's caused by r == HUGE_VAL condition in
if (ep == s || r == HUGE_VAL || errno == ERANGE)
where r is NaN.
All the signs indicate there is a bug in QEMU.
I'll install 5.1, but on 4.0 which I had installed, the program works fine:
$ ./sigfpe
is a number
nan
I just tested on NetBSD 5.0/SPARC under QEMU 0.13 (same version I use
with NetBSD 5.1/SPARC) and it works well indeed:
mloskot@qemu-netbsd-50-sparc:~/tmp# ./a.out
is a number
nan
mloskot@qemu-netbsd-50-sparc:~/tmp#
Hmm, this is becoming interesting.
I run QEMU 0.13 on Windows Vista (64-bit).
Perhaps host system and QEMU binaries are relevant here.
I will try on Linux host system later tonight.
BTW, here are my images:
http://mateusz.loskot.net/tmp/qemu/
Best regards,
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
Member of ACCU, http://accu.org
Re: [Qemu-devel] [sparc] Floating point exception issue
On Tue, Jan 18, 2011 at 3:27 PM, Mateusz Loskot wrote:
> Hi,
>
> Recently, I have reported mysterious issues on NetBSD 5.1
> emulated on SPARC. The whole first thread is here:
>
> http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
>
> I decided to investigate the problem deeper and with great help
> from NetBSD folks, I managed to find reproducible test case.
> Initially, it was AWK command:
>
> # echo NaN | awk '{print "test"}'
> awk: floating point exception 8
> source line number 1
>
> and next it boiled down to simple C program (see below).
> Details of the investigation are archived in the NetBSD Problem
> Report #44389 here:
>
> http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
>
>
> Here is final version of the test program which reproduces the problem:
>
> #include
> #include
> #include
> #include
>
> int is_number(const char *s)
> {
> double r;
> char *ep;
> errno = 0;
> r = strtod(s, &ep);
> if (r == HUGE_VAL)
> printf("X:%g\n", r);
>
> if (ep == s || r == HUGE_VAL || errno == ERANGE)
> return 0;
> while (*ep == ' ' || *ep == '\t' || *ep == '\n')
> ep++;
> if (*ep == '\0')
> return 1;
> else
> return 0;
> }
>
> int main(int argc, char **argv)
> {
> double v;
>
> if (is_number("NaN")) {
> printf("is a number\n");
> v = atof("NaN");
> } else {
> printf("not a number\n");
> v = 0.0;
> }
> printf("%.4f\n", v);
>
> return 0;
> }
>
>
> On NetBSD/SPARC, the program receives SIGFPE:
>
> $ gcc ./nan_test_2.c
> $ ./a.out
> [1] Floating point exception (core dumped) ./a.out
>
> Specifically, it's caused by r == HUGE_VAL condition in
> if (ep == s || r == HUGE_VAL || errno == ERANGE)
> where r is NaN.
>
> All the signs indicate there is a bug in QEMU.
I'll install 5.1, but on 4.0 which I had installed, the program works fine:
$ ./sigfpe
is a number
nan
[Qemu-devel] [sparc] Floating point exception issue
Hi,
Recently, I have reported mysterious issues on NetBSD 5.1
emulated on SPARC. The whole first thread is here:
http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01509.html
I decided to investigate the problem deeper and with great help
from NetBSD folks, I managed to find reproducible test case.
Initially, it was AWK command:
# echo NaN | awk '{print "test"}'
awk: floating point exception 8
source line number 1
and next it boiled down to simple C program (see below).
Details of the investigation are archived in the NetBSD Problem
Report #44389 here:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=44389
Here is final version of the test program which reproduces the problem:
#include
#include
#include
#include
int is_number(const char *s)
{
double r;
char *ep;
errno = 0;
r = strtod(s, &ep);
if (r == HUGE_VAL)
printf("X:%g\n", r);
if (ep == s || r == HUGE_VAL || errno == ERANGE)
return 0;
while (*ep == ' ' || *ep == '\t' || *ep == '\n')
ep++;
if (*ep == '\0')
return 1;
else
return 0;
}
int main(int argc, char **argv)
{
double v;
if (is_number("NaN")) {
printf("is a number\n");
v = atof("NaN");
} else {
printf("not a number\n");
v = 0.0;
}
printf("%.4f\n", v);
return 0;
}
On NetBSD/SPARC, the program receives SIGFPE:
$ gcc ./nan_test_2.c
$ ./a.out
[1] Floating point exception (core dumped) ./a.out
Specifically, it's caused by r == HUGE_VAL condition in
if (ep == s || r == HUGE_VAL || errno == ERANGE)
where r is NaN.
All the signs indicate there is a bug in QEMU.
Best regards,
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
Member of ACCU, http://accu.org
