| 摘要 |
A metal-oxide-semiconductor (MOS) partitioned carry lookahead adder fabricated from a plurality of four bit slice blocks. Each block provides four sum signals and provides a block carry signal. The blocks are organized into groups of optimum size with logic in each group to generate a group propagate signals. Each block has a block carry line with a single transistor connected between the input and output terminals of the block. The blocks employ an intermediate carry circuit for computing sums in place of full adders. In addition, there is a main carry line with transistors controlled by the group propagate signals for a 32 bit adder, the maximum pass gate delay in the carry chain is three pass gates.
|
