Comment 1 for bug 1668041

Hi,

This problem still exists on QEMU 5.0.0 both for i386 and x86_64;
floating-point zero division is not trapped at all, while integer
one is trapped correctly.

This seriously affects NetBSD project, which carries out periodic
regression tests on QEMU:

https://releng.netbsd.org/test-results.html

Tests including floating-point zero division are falling on QEMU,
while they are successfully passing on real hardwares.

HOW TO REPEAT:

Compile and run this program on Unix like operating systems:

---
#include <fenv.h>
#include <stdlib.h>
#include <unistd.h>

int
main(void)
{
        volatile double a = getpid();
        volatile double b = atoi("0");

        feenableexcept(FE_ALL_EXCEPT);

        usleep((int)(a / b));

        return 0;
}
---

It crashes by SIGFPE on real hardware, but normally exits on QEMU.

I ran this program on NetBSD 9.0 for x86_64 and i386 on QEMU 5.0.0:

(1) Obtain NetBSD 9.0 release from here:

For x86_64:
http://cdn.netbsd.org/pub/NetBSD/NetBSD-9.0/images/NetBSD-9.0-amd64.iso

For i386:
http://cdn.netbsd.org/pub/NetBSD/NetBSD-9.0/images/NetBSD-9.0-i386.iso

(2) Install it for disk image.

(3) qemu-system-x86_64 NetBSD.qcow2 or qemu-system-i386 NetBSD.qcow2

(4) Compile and run the test program above:

# cc fpe.c -lm -o fpe
# ./fpe

(5) Then, it exits normally, while it should abort due to SIGFPE.