64-bit problem with Sun Ultra-5

[Paul Kinzelman <pkinz at timesync dot com>]

I'm running gcc version 2.8.1on:
Sun: Ultra 5 running Solaris 7 (uname says SunOS 5.7)
RedHat6: Pentium-2, 233MHz running Linux 2.2.5-15

If I do the following:
  unsigned long x, y;
  unsigned long long z;
  x = 123;
  y = 456;
  z = (((unsigned long long)y) * 1000000000) + x;
  printf ("y,x=%ld,%ld; z=%Ld\n", y, x, z);

The printf shows:
Sun:    y,x=456,123; z=106     [bogus]
RH6:   y,x=456,123; z=456000000123 [correct]

I tried these alternatives with the same result:
  z = (y * 100000000ULL) + x;
  z = (y * ((unsigned long long)100000000)) + x;

I got down this path because I was getting bogus answers
elsewhere in the program I was writing, so
I think the problem is more than just how they print.

Any help would be greatly appreciated!

--
-Paul Kinzelman, San Jose, CA, ISD Corp