Pipelining can be applied within the ALU to speed up floating-point operations. Consider the case of floating-point addition and subtraction. In simplified terms, the pipeline could have four stages: (1) Compare the exponents; (2) Choose the exponent and align the significands; (3) Add or subtract significands; (4) Normalize the results. The pipeline can be considered to have two parallel threads, one handling exponents and one handling significands, and could start out like this:

In this figure, the boxes labeled R refer to a set of registers used to hold temporary results. Complete the block diagram that shows at a top level the structure of the pipeline.

Exponents Significands A B