Ifs and Whiles

More trickery is used to create a 32-bit branch address out of the smaller sized field of the  beq   instruction. But let's skip that for now.

Branch instructions (including the beq instruction) are used to implement both loops and branches. At right is a flowchart showing an optional branch. Here is the assembly language for it:

        ...                # load values into $8 and $9 
        beq  $8,$9,cont    # branch if equal
        sll  $0,$0,0       # branch delay slot
        ...                # conditionally
        ...                # executed
        ...                # statements
cont:   add   $10,$10,$11  # always executed

(Any instruction can be a target of a branch. The add instruction is here just as an example.)