"opcode not supp'd" while crosscompiling kernel

[Oliver Frommel <oliver@aec.at>]

hello,

using binutils-2.7-4, gcc-2.7.2-4 and kernel linux-970701 from ftp.linux.sgi.com
/pub/linux/mips/testing crosscompiling the kernel works fine until this point:

mips-linux-gcc -D__KERNEL__ -I/usr/people/oliver/linux-dir/linux-970701/include 
-Wall -Wstrict-prototypes -O2 -fomit-frame-pointer -G 0 -mno-abicalls -fno-pic 
-g -mcpu=r4600 -mips2 -pipe -c gdb-low.S -o gdb-low.o
gdb-low.S: Assembler messages:
gdb-low.S:301: Error: opcode not supported on this processor `eret'
make[1]: *** [gdb-low.o] Error 1

what's going wrong this time ? :) 
thx, oliver