| 摘要 |
The tetrad adder according to the inventive subject matter consists of a dual tetrad adder (main circuit 7) and a correction circuit 18 for subtracting the number 6 (LHHL), which is acted upon by the negated carry output y or a negated branch of this carry output. One of the two summands is input in BCD 6 code. If no carry comes about in the main circuit 7, H potential is applied to the correction circuit 18 via the line c, and thus the number 6 (LHHL) is subtracted from the result number of the main circuit 7, and thus the result number of the main circuit 7 is converted from BCD 6 to BCD 0. If a carry comes about in the main circuit 7, the result number already occurs in the main circuit 7 in BCD 0 code. In this case, the line c has L potential, and thus only the number 0 (LLLL) is subtracted from the result number of the main circuit 7. Consequently, the addition result number occurs in both cases in BCD 0 code. <IMAGE>
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