17. Carc 03.04
alessandro.bogliolo@uniurb.it
Carry Lookahead Adder (CLAn)
Observations:
ci = ai*bi + (ai+bi)ci-1 = gi + pi * ci-1
The first term generates the carry out (generate gi = ai*bi)
The second term propagates the carry (propagate pi = ai+bi)
Implementation:
ci = gi + pi (gi-1+pi-1 (gi-2+pi-2( ... (g0+p0*Cin)...)))
ci = gi + pigi-1+pipi-1gi-2+ pipi-1pi-2gi-3 + ... + pipi-1pi-2 ...p0Cin
(2)
(3)
(1)