Carry-select Adder - Basic Building Block

Basic Building Block

Above is the basic building block of a carry-select adder, where the block size is 4. Two 4-bit ripple carry adders are multiplexed together, where the resulting carry and sum bits are selected by the carry-in. Since one ripple carry adder assumes a carry-in of 0, and the other assumes a carry-in of 1, selecting which adder had the correct assumption via the actual carry-in yields the desired result.

Read more about this topic:  Carry-select Adder

Famous quotes containing the words basic building, basic, building and/or block:

    Of course I lie to people. But I lie altruistically—for our mutual good. The lie is the basic building block of good manners. That may seem mildly shocking to a moralist—but then what isn’t?
    Quentin Crisp (b. 1908)

    The basic tool for the manipulation of reality is the manipulation of words. If you can control the meaning of words, you can control the people who must use the words.
    Philip K. Dick (1928–1982)

    The limits of prudence: one cannot jump out of a burning building gradually.
    Mason Cooley (b. 1927)

    Painting consumes labour not disproportionate to its effect; but a fellow will hack half a year at a block of marble to make something in stone that hardly resembles a man. The value of statuary is owing to its difficulty. You would not value the finest head cut upon a carrot.
    Samuel Johnson (1709–1784)