in arch/mips/Makefile, we use the -mcpu=r4600 flag for MIPS32. What's 
interesting is that the use of this flag can cause the toolchain to 
generate incorrect code. For example:

la k0, 1f
nop
1: nop


The la macro is split into a lui and a daddiu. The daddiu is not correct 
for a mips32 cpu.  Getting rid of the -mcpu=4600 fixes the problem and 
the daddiu is then changed addiu.

Is there a truly correct -mcpu option for a mips32 cpu?

Pete