International Business Machines Corporation

Jose Roriz Sousa

James J Covino

Roy Childs Flaker

Alan L Roberts

Luigi Ternullo, Jr

Garrett Stephen Koch

John P Connor

Robert Dean Adams

An associated memory structure having a plurality of memories amenable for testing and a method of testing the memories is provided. First and second memories are formed, wherein data in the first memory provides a basis for at least a portion of the input to the second memory during functional operation of two memories. Preferably, an output latch for receiving the output test data from the first memory is provided. Means are provided for loading the first memory with data which is utilized as a basis for providing at least a portion of the input to the second memory. An access path from the output port of the first memory to the input port of the second memory allows use of the data in the first memory to generate at least a portion of the input to the second memory. The first memory is first tested independently of the second memory. Thereafter, the first memory is loaded with preconditioned data that is used as a basis for inputs to the second memory during testing of the second memory. The second memory is then tested by generating inputs to the first memory during testing of the second memory. Thus, outputs of the first memory constitute at least a portion of test data inputted to the second memory. A latch is provided to capture the output of the test data from the second memory.

Using one memory to supply addresses to an associated memory during

A structure and method of operation of a cache memory are provided. The cache memory is organized such that the data on a given line of any page of the main memory is stored on the same line of a page of the cache memory. Two address memories are provided, one containing the first eight bits of the virtual address of the page of the data in main memory and the second the entire real page address in main memory. When an address is asserted on the bus, the line component of the address causes each of those lines from the cache memory to read out to a multiplexor. At the same time, the eight bit component of the virtual address is compared in the first memory to the eight bits of each line stored in the first memory, and if a compare is made, the data on that line from that page of cache memory is read to the CPU. Also, the entire real address is compared in the second memory, and if a match does not occur, the data from the cache to the CPU is flagged as invalid data. A structure and method are also provided to determine if duplicate addresses exist in the second address memory.

Method and structure for accessing semi-associative cache memory using

A method and apparatus are provided for parallel addressing a CAM and a RAM, and also for using a single wordline to address the CAM and/or RAM. The CAM and RAM are addressed using a common wordline, and the common wordline is also used for writing to the CAM during a write cycle and strobing the CAM during a read cycle.

Method and apparatus for parallel addressing of CAMs and RAMs

A truc/complement receiver driver circuit in which the input signals may be applied prior to a sysnchronous clock signal. The input signals are sensed and latched to generate complementary output signals. The generation of the output signals causes the receiver portion of the circuit to be automatically reset for the next cycle. The leading edge of the systemclock causes the circuit outputs to reset and enables the receiver circuit to be enabled for the next cycle. Multiplexed input receiver circuits allow the circuit to respond to a plurality of input signal sources.

Address buffer for synchronous system

A low power, high speed, multistage asynchronous logic circuit having an interlocked restore mechanism. A first logic circuit detects a valid input signal and drives an output to a second logic circuit. The second logic circuit receives inputs from the first logic circuit and drives a data ready signal back to the first logic circuit when it detects the output from the first logic circuit. The first logic circuit resets when it receives the data ready signal from the second logic circuit and it detects that its inputs have been reset.

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Colchester, VT, United States of America

Jose Roriz Sousa