Uresolved Symbol problem in kernel compiled for ATHLON :(

[Pablo Giménez Pizarro]

Hi all.
I've compiled a kernel optimized for aTHLON processors and when i reboot 
i get the next error nwhen try to load some modules:

/lib/modules/2.4.20/kernel/drivers/net/dmfe.o: unresolved symbol _mmx_memcpy

The next errors are the usual insmod errors in this cases.
I get this unresolved symbol message with other modules like nfs.o, in 
general with net modules and filesystems modules.
If i compile the kernel for a Pentium Pro or lower micro i don't get 
this errors, so i think this is a problem with the ATHLON optimization, 
the kernel version i tried are 2.4.19 and 2.4.20.
I could compile the 2.4.19 for ATHLON in previous times, but now i can't.
Any clue :?

Thanks!!