Q: Compiles for wrong processor and it still worked

[Erik Trulsson]

On Sun, Sep 28, 2003 at 07:37:59PM +0200, Alex de Kruijff wrote:
> I have compiles my world sources for the PIII processors. I have
> recently discoverd that i have a number of PII processors. The compiled
> code for PIII still works on them. I'm ammazed. :o Can anybody explain why?

The reason why it worked is obviously that the compiler didn't generate
any PIII-only instructions in the code.

The only real difference between PII and PIII is that the PIII has
support for SSE, which most compilers don't use anyway, so it is not
very amazing that code compiled for a PIII worked on a PII.

If you are running -stable it is even less amazing since the compiler
included in 4.x is too old to know how to optimize for the PIII, so it
will generate identical code for all the processors based on the P6
micro-architecture (i.e the Pentium Pro, Pentium II and Pentium III) as
well as for the newer Pentium 4.


-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at student.uu.se