Amdahl Corporation

Michael J Begley

Joseph A Petolino

Jeffrey A Thomas

Michael DeMar Taylor

Allan J Zmyslowski

Robert M Maier

Ajay K Shah

Richard J Tobias

Jack Chen

An apparatus and method for use in improving cache storage unit utilization during an interlock of an instruction pipeline generates a control signal during one cycle of the interlock if the interlocked instruction may require storage unit management work. In response to the control signal, selector control logic in the storage unit generates a priority signal indicating the interlocked instruction for selection by the storage unit for processing. In response to the control signal and the priority signal, the cache management logic is used during the interlock on the interlocked instruction to prepare for supplying needed data when the interlock is released.

Apparatus and method for improving cache access throughput in pipelined

Bypassing of data from a main storage unit to an instruction and operand processing unit around an intermediate storage unit improves performance in a data processing system. The instruction and operand processing unit supplies requests for operands to the intermediate storage unit or cache. If the line is missing from the cache, the request operand is retrieved from the main storage unit. A bypass data path is connected between the main storage unit, prior to error detecting means in the cache, and the instruction and operand processing unit for transferring requested operands to the instruction and operand processing unit directly. Control, coupled to receive requests for operands and to the instruction and operand processing unit, signals the instruction and operand processing unit to receive the requested operands from the bypass data path when the data includes a requested operand.

Cache move-in bypass

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San Jose, CA, United States of America

Michael J Begley