Can I crosscompile a driver with an intel dualcore processor to be used in a celeron machine, and if so, the how? Both machines are running Linux Mint 7. The driver in question is ov51x-jpeg.

You should provide more info about what it is you're working with. That said, I am fairly sure there isn't going to be any difference if you haven't asked for some kind of multi-threaded optimizations or libraries, and I am entirely sure that it will run on both systems either way.

I wonder if I could compile the web camera (Creative Live cam vista IM)
driver for someone else's celeron machine running Linux Mint 7.

The driver is ov51x-jpeg

I could install Linux Mint 7 on 4 different machines, one of which is has AMD Athlon, one has AMD 3-core, one has dual core T2410 and one has an Intel dual core (I don't remembet which dual core).

I guess AMDs are different in some respects, but are Intel dual cores?
(I mean compiler produced binary here)
Do I have to use cross-compilation? If so, how do I get gcc to compile for another architecture?

How do you know you have a problem?

I don't. That's why I'm asking.

At least the kernel is different for AMD. I guess GCC uses processor specific features for more optimal binary. To my knowledge AMD and Pentium have differencies in instruction set even if there is quite large common subset. It's just if GCC might use the specific instructions.

Another matter is multicore pentium. Does it (could it) show in the GCC-generated code if code is compiled for a multicore pentium?

I'd also like to know what should I do to to be able to cross-compile with GCC for another processor architecture.

Ah, gotcha. You should be fine - the differences between AMD and Intel are small and tend to be relevant only in extremely specific circumstances (as there is some adoption of each others' instructions and little use of instructions that aren't valid on both). Also, unless you are writing significant parallelization into your code, there's no reason to worry about that, either (and I'm not sure gcc even has a 'multithreading' mode, since that functionality kind of exists above the level gcc works on, if you get me). Just compile normally and your program will work on all x86 and x86-compatible (read: x86-64) processors. Note that your distro does not have separate repos for AMD, Intel, 2x-SMT, 8x-SMT, and so on - just x86 and x86-64.

If you do want to cross-compile - and we're talking about PPC, ARM, etc. here - I believe there is a -march option to gcc, but you will have to research that yourself if you're interested.

OK, I'll try. Thanks.