| 摘要 |
PURPOSE:To obtain a 4-fold circuit without the need for sequential carry, by forming AND gates with 2-digit positive signals, 4-signals, one digit negative signals, 5 or 4-signals and cutting of the AND gates of 2-digit positive signals and 4-signals through the output. CONSTITUTION:Seven sets of FFs indicating one digit of + or - quinary numbers are arranged at the lower end, a code bit S2 is located at the left end and a code bit S1 lower by one digit is located at the right end. Code 1 shows positive and 0 shows negative. The output of 5 goes to the carry 2 and the output 0, and the output of 4 passes through a gate G4 at S2=1. With the signal 4 at S2=1, and when one digit is 5 or 4 at S1=0, a gate G6 is set. Since the NOT at the output of the G6 is connected to the G4, the signal goes to 16 at the G6 set to ON, the G4 is cut off and no recarry takes place. |
