Fast ALU equals zero circuit

摘要

A fast ALU=0 circuit is used with a carry-select lookahead ALU. Preliminary ALU=0 signals are derived for each section of the ALU prior to a carry in signal being received by that section. When the carry in signal is received, a final comparison is made with the least significant bit of the section and the final ALU=0 signal generated. The ALU=0 computation is complete one gate delay after the ALU computation is complete.