BIT OPERATION METHOD AND CIRCUIT FOR MICROCOMPUTER

A microcomputer circuit is described for carrying out bit operations between registers and ports without the need for bit testing followed by branch operations. The microcomputer includes a bus (10) connected to provide communication to an ALU (22), registers (11, 12) and a serial port (13). A bit test circuit is connected to the bus (10) and provides a selected bit to a temporary carry storage (18) which in turn transfers the selected bit to a carry flag location (28a) within a status register (28). Instruction codes are input to an instruction register (32) which provides operating commands to an entry ROM (36) and an ALU control circuit (40). After a bit test operation is completed and in response to a copy or exchange instruction provided to the instruction register (32) a bit can be copied from one register to another register, bits can be exchanged between two registers or bits within a register can be parallel-to-serial converted and provided to the serial port (13). Each of these operations is carried out without the need for employing branch operations following the test of a bit. The present invention provides dynamic bit operations without the need for testing the state of a bit to determine conditional branching for selecting set or clear operations. With the present invention the speed of bit operations is improved and the amount of code stored in program memory can be reduced.