V22.0436 - Prof. Grishman

Lecture 8 - Carry look-ahead

(demonstrate wire bundles for Assignment #3)

(discuss MIPS ALU -- Lecture 7 notes)

Carry look-ahead (Apppendix C.6)

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.