Cross-compilation Options for IDT MIPS Architecture

["P.Srihari" <srihari dot par at wipro dot com>]

i am facing a problem described as follows :

we have a software, which has been compiled and well tested on x86 
architecture on linux. 

now the same software, has to be executed on IDT MIPS - to be specific
IDT 79RC32T355 architecture. for this, mipsel-linux-gcc is being used as 
the cross compiler. i have given the following compilation options :

        -mips2 -EL 

but when the software is executed, it results in SIGILL - illegal 
instruction. the program counter points to the following instruction

        lui $at, 0x4000 

is this instruction not legal for the specific architecture ??

the function, which resulted in this had some double data types, which
we changed to int and the problem is no longer occuring.

all the .o files have been compiled, using these flags. the executable
links with some shared libraries also.

so the question : 

        1. what are the options that have to be given along with the
        cross compiler/linker

        2. any specific requirements during compilation and 
        linking that may have impact on the final executable

is there any web-site where compiler/linker options are explained
from the IDT architecture perspective.

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