The high-speed CMOS adding machine by null carrying looking ahead

摘要

Topic Make the accumulation depth of the P channel inside critical route of thing and the carrying looking ahead adding machine decrease which improve the speed of the carrying looking ahead adding machine.SolutionsThe null carrying looking ahead adding machine, in order to form and to be spread and is formed the null carrying signal/via inside the group of block and block inside the adding machine. The null carrying signal exceeding the point where that null carrying signal is formed ends the effect of the carrying input signal. To improve the speed of the null carrying looking ahead adding machine substantially it is possible the largest accumulation depth 2 of the P channel in case of adding machine block of 4 bits by deciding the rule in order it forms and to be spread and, via the group of block and block inside the adding machine be able to achieve the null carrying signal, by comparison with the former carrying looking ahead adding machine which is based on the formation and propagation of the carrying signal inside the adding machine with this. Selective figure Figure 10