V22.0436 - Prof. Grishman

Lecture 12 - Carry look-ahead

(text, section 4.5)

(finish discussion of MIPS ALU - lecture 9 notes)

Carry look-ahead

We can speed up addition by introducing notion of "carry generate" and "carry propagate": We get greater savings when we build a 16-bit adder, and compute group generate and propagate values for each 4-bit group. Note that group values are designated by capital letters. Spring 1999