| 摘要 |
PURPOSE: A digital calculator is provided to reduce a production cost by using smaller quantity of gates, and to enhance a calculation speed by shortening a calculation path. CONSTITUTION: A digital calculator comprises an inverter(INV), half adders, and an exclusive OR gate(XOR7). The inverter(INV) inverts the uppermost bit among input bits, and outputs the inverted value as the uppermost bit value of a calculation result value. The half adders, performing a half addition from a second highest bit to a second lowest bit, includes exclusive OR gates performing an exclusive OR logic action on the tow inputs, a corresponding bit value and a former rank bit value, and an AND gate performing an AND logic action on the two inputs, a corresponding bit value and an output value of a former AND gate. The exclusive OR gate(XOR7) performs an exclusive OR logic action on the two inputs, the lowest bit value and the output of a former AND gate.
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