METHOD AND APPARATUS FOR GENERATING FLAGS FOR A PROCESSOR

摘要

A method and apparatus are described for generating flags in response to processing data during an execution pipeline cycle of a processor. The processor may include a multiplexer configured generate valid bits for received data according to a designated data size, and a logic unit configured to control the generation of flags based on a shift or rotate operation command, the designated data size and information indicating how many bytes and bits to rotate or shift the data by. A carry flag may be used to extend the amount of bits supported by shift and rotate operations. A sign flag may be used to indicate whether a result is a positive or negative number. An overflow flag may be used to indicate that a data overflow exists, whereby there are not a sufficient number of bits to store the data.