A method of designing a logic circuit including pass transistors is
disclosed. A logic group having a complementary variable in a given
logical expression to be realized into the logic circuit is mapped using
a multiplexer composed of a combination of the pass transistors. The
number of transistors used in the logic circuit and the number of stages
can be reduced by taking advantage of the multiplexer. When a logic
circuit including both pass transistors and a multiple-input logic gate
is designed, a logic group having a common variable in the given logical
expression is mapped using the multiple-input logic gate. The number of
transistors used in the logic circuit and the number of stages can be
further reduced by taking advantage of the multiple-input logic gate. In
order to ease the above mapping procedure, a complementary variable is
identified and the given logical expression is optimized by grouping
product terms of the logical expression by the complementary variable.
Furthermore, a common variable is identified, and the logical expression
is further optimized by grouping product terms of the logical expression
by the common variable.