Mips, self modifying code

hi, i need help with self modifying code.

the assignment is to actually write a calculator program. it basically takes some input binary,decimal,hex and does 4 operations +,-,*,/ but there is a special case where when the result is 7 the program will modify itself so that from then on entering addition will instead give the logical AND of the two operands.
I dont know anything about self modification.

I don't know any MIPS, but the idea is to write to the part of memory where the code itself resides. It's easier if the modifications don't change the size of the code. You still need to know the exact memory address of the instruction(s) you want to change, but perhaps the assembler will compute this for you.

Here's a quick example in pseudo-assembly: suppose you have the following instruction that adds register reg1 to reg2:
You want to change this to an AND operation:

For simplicity, let's assume registers and instructions are the same size in bits, say 32 bits. (This is often not the case, and I don't know about MIPS specifically.) You need to put your replacement instruction somewhere: Put it somewhere where it won't be executed, since it isn't going to be part of the program initially. Now you write the replacement instruction to memory to replace the initial one: There are several things that can make this more complicated, some of which I have indicated, but I only wanted to give you the gist of it, since you said you didn't know anything. Good luck!

thank you very much . stupid self modification was frying my brain lol i did everything but that *sigh*

omg after spending hours on this from reading to book to surfing i couldn't do it!!!
but your explanation was all i needed.. thank you very much !!!!!!!!!!!!!!!!!
I LOVE YOU!!!!!!!!!