Abstract: In a pipelined computer architecture in which instructions may be removed from the instruction queue out of sequence, instruction queue status at a cycle K is determined by adding together the number of invalid instructions or free rows in the queue during cycle K?2, the number of instructions issued for cycle K?1 and the number of instructions speculatively issued in cycle K?1 that have produced a cache hit, and subtracting from the sum the number of instructions enqueued for cycle K?1. The result indicates the number of invalid instructions in the queue cycle K. The number of invalid entries instructions, the number of issued instructions, and the number of enqueued instructions are preferably represented as flat vectors, so that adding is performed by shifting in one direction, while subtracting is performed by shifting in the opposite direction. The result is compared with either the number of instructions to be enqueued in the present cycle, which number is encoded, or with a predetermined value.

Abstract: The present invention is directed to a method for evaluating a circuit design to identify potential race conditions including the steps of identifying switching elements in a design, storing control node and switched node pair information for each of the switching elements, identifying stacks of the switching elements; storing information about the stacks of switching elements; identifying parallel connected ones of the switching elements; identifying parallel stacks; and calculating a combined switching current for the parallel switching elements and stacks.

Abstract: The present invention is directed to a method for evaluating a circuit design to identify potential race conditions including the steps of identifying switching elements in a design, storing control node and switched node pair information for each of the switching elements, identifying stacks of the switching elements; storing information about the stacks of switching elements; identifying parallel connected ones of the switching elements; identifying parallel stacks; and calculating a combined switching current for the parallel switching elements and stacks.

Abstract: In a pipelined computer architecture in which instructions may be removed from the instruction queue out of sequence, instruction queue status at a cycle K is determined by adding together the number of invalid instructions or free rows in the queue during cycle K−2, the number of instructions issued for cycle K−1 and the number of instructions speculatively issued in cycle K−1 that have produced a cache hit, and subtracting from the sum the number of instructions enqueued for cycle K−1. The result indicates the number of invalid instructions in the queue cycle K. The number of invalid entries instructions, the number of issued instructions, and the number of enqueued instructions are preferably represented as flat vectors, so that adding is performed by shifting in one direction, while subtracting is performed by shifting in the opposite direction.

Abstract: In a pipelined computer architecture in which instructions may be removed from the instruction queue out of sequence, instruction queue status at a cycle K is determined by adding together the number of invalid instructions or free rows in the queue during cycle K−2, the number of instructions issued for cycle K−1 and the number of instructions speculatively issued in cycle K−1 that have produced a cache hit, and subtracting from the sum the number of instructions enqueued for cycle K−1. The result indicates the number of invalid instructions in the queue cycle K. The number of invalid entries instructions, the number of issued instructions, and the number of enqueued instructions are preferably represented as flat vectors, so that adding is performed by shifting in one direction, while subtracting is performed by shifting in the opposite direction.

Abstract: A technique for processing register instructions in a pipeline data processor in which multiple instructions may be processed concurrently, and may therefore conflict with one another. Register instructions are identified with register groups indicating which processor registers are affected by the execution of the register instruction. The progress of the execution of the register instruction is then controlled depending upon the identified register groups, in order to avoid conflicts with other concurrently processed instructions.

Abstract: A technique for speculatively issuing instructions using an out-of-order processor. A cache miss by a load instruction results in either a reissue of all subsequently issued instructions for an integer instruction stream, or a reissue of only truly dependent instructions for a floating point instruction stream. One version of the technique involves issuing and executing a first instruction, and issuing a second instruction during a speculative time window of the first instruction that occurs after the first instruction is issued. The technique further involves executing the issued second instruction when the first instruction is executed in a first manner, and reissuing the second instruction and executing the reissued second instruction when the first instruction is executed in a second manner that is different than the first manner.