Sorry, by "Intel chip" I meant a Pentium 4.

To check the results I don't do any printf's so that's not the problem. The 8051 is attached to an FPGA which is attached to an LED. I've written my program in such a way that a 1 is output to the LED if the results match, and a 0 if they don't.

About the "strange things"... I'm not really seeing any strange things, just wrong results. I'm guessing that multiplication and division is the problem because there are a number of other algorithms, which I have implemented which don't use any multiplication or division, and the results match just fine.