| 摘要 |
A carry propagation circuit generating a block carry propagation function P as a signal at an intermediate junction of a carry lookahead circuit, on the basis of input two numbers A and B, and a carry generation circuit for generating a block carry generation function G on the basis of the two numbers A and B, are provided. When a carry input is O, a carry co is the same value to the block carry generation function G. On the other hand, when the carry input is 1, the carry C1 is an OR of the block carry generation function G and the block carry propagation function P, which can be obtained by an OR circuit. Two sums S0 and S1 are derived from two carries and an exclusive OR of two numbers A and B by exclusive OR circuits.
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