Method and device for performing modulo-based arithmetic operations in an asynchronous transfer mode cell processing system

摘要

Methods and apparatus for processing cells in an asynchronous transfer mode (ATM) communication system. An ATM cell processor provides a modulo arithmetic feature which permits branching on the modulo portion of the result of an arithmetic operation. An arithmetic logic unit (ALU) or other processor instruction is modified to include a modulo field which specifies the number of right to left bits after which the result of the corresponding ALU operation will be truncated. Conditional branch instructions such as branch on zero result, branch on non-zero result, branch on negative result, branch on carry and branch on overflow may be configured to operate only on the modulo portion of the ALU instruction result and/or on a carry out of the most significant bit (MSB) position of the modulo portion.