Write the MIPS assembly code to implement the following C code:
lock(lk);
shvar=max(shvar,x);
unlock(lk);
Assume that the address of the lk variable is in $a0, the address of the shvar variable is in $a1, and the value of variable x is in $a2. Your critical section should not contain any function calls. Use ll/sc instructions to implement the lock( ) operation, and the unlock() operation is simply an ordinary store instruction.