Hi!  This is NOT a NetBSD bug, but I'm really curious as to whether anyone's
seen it.

This program reliably hangs three different AMD64 machines, all of them
Athlons, and all with nForce4 chipsets.  I would love to know more cases
where it works or doesn't.  Hangs have been observed under 64-bit Linux
and 32-bit Windows.

        #include <string.h>
        unsigned char a[4*1024*1024];

        int
        main(void) {
                while (1)
                        memset(a, 0, 4*1024*1024);
                return 0;
        }

This program 100% reliably hangs my Athlon64 box.  It takes under 10 seconds
under Linux, several minutes on Windows.  And no, that doesn't make any sense.
I don't have any EM64T boxes handy for testing.

-s