SU1658145A1 - Four-input single-bit adder - Google Patents

Abstract

The invention relates to computing and is intended to build high-speed arithmetic devices of computers and special processors. The purpose of the invention is to simplify the adder. The adder contains two elements of addition modulo 2 1, 2, majority element 3 and element 4. It has four inputs 5-8 and three outputs 9-11. The binary variables xi, X2, xs, x-, and the logic functions fo are implemented at the inputs of the adder. fi, f2, corresponding to the sum, junior, and higher carry signals. 1 ill., 1 tab.

Description

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The invention relates to computing and is intended to build high-speed arithmetic devices of computers and special processors.

The purpose of the invention is to simplify the adder.

The drawing shows a four-input single-bit adder circuit.

The adder contains two elements Modulo two and 1 and 2, the majority element (with a threshold of 2) 3, the element And 4, four inputs 5-8, outputs 9 sums, outputs 10 and 11 of the junior and senior hyphenation,

The four-input one-bit adder operates as follows.

From inputs 5-8, binary variables xi, x2, xs, x4 are supplied, respectively. The output 9 is implemented logical functions

fo x1®x2fhah,

corresponding to the sum signal. The output 10 is implemented logical functions

fl X1X2X3X4® M2 (X1, X2, X3, X),

corresponding to the low carry signal. The output 11 is implemented logical functions

f2 X1X2X3X4,

corresponding to the senior carry signal.

Here M (x1, x2, xs, x4) is the function of the majority element (with threshold 2);

M2 (X1, X2, X3, X4)

1, if Xi + X2 + xs -I-X4 2, 0, if xi + X2 + xs + X4 1. The values of the logical functions implemented by the four-input single-bit adder are presented in the table.

Claims (1)

Invention Formula A four-input single-bit adder containing the element And and two elements Addition modulo two, the inputs of the first element Addition modulo two are connected to the inputs of the adder from first to fourth, and the output is connected to the output of the sum of the adder, the output of the lower transfer modulo adder two, the first input which is connected to the output of the element And, the first and second inputs of which are connected to the corresponding inputs of the adder, characterized in that, for the purpose of simplification, the adder contains the majority element, the output of which is connected to the second a second swing member Addition modulo two and the inputs of the adder are connected to inputs of the first through the fourth, third and fourth inputs of the adder connected to respective inputs of AND member, whose output is connected to the output of the adder older transport.