| Carry lookahead | |||||||||||||
| Can calculate carries in parallel | |||||||||||||
| Tradeoff: need more hardware (space vs. time) | |||||||||||||
| Boolean expression for carry-out: | |||||||||||||
| cout = \xycin + x\ycin + xy\cin + xycin | |||||||||||||
| What does this expression look like? | |||||||||||||
| z = \abc + a\bc + ab\c + abc | |||||||||||||
| How many inputs? | |||||||||||||
| How many need to be true? | |||||||||||||
| What is that function called? | |||||||||||||