Abstract: A processor including an architecture for limiting store operations includes: a data input and a cache input as inputs to data merge logic; a merge buffer for providing an output to an old data buffer, holding a copy of a memory location and two way communication with a new data buffer; compare logic for receiving old data from the old data buffer and new data from the new data buffer and comparing if the old data matches the new data, and if there is a match determining an existence of a silent store; and store data control logic for limiting store operations while the silent store exists. A method and a computer program product are provided.

Abstract: A processor includes a microarchitecture for working around a processing flaw, the microarchitecture including: at least one detector adapted for detecting a predetermined state associated with the processing flaw; and at least one mechanism to modify default processor processing behavior; and upon modification of processing behavior, the processing of an instruction involving the processing flaw can be completed by avoiding the processing flaw.

Abstract: A method and system for instruction address parity comparison are provided. The method includes calculating an instruction address parity value for an instruction, and distributing the instruction address parity value to one or more functional units in processing circuitry. The method also includes receiving the distributed instruction address parity value from the one or more functional units, and calculating a completing instruction address (CIA) parity value associated with completing the instruction. The method further includes generating an error indicator in response to a mismatch between the received instruction address parity value and the CIA parity value.

Abstract: A system and method for overlapping execution (OE) of instructions through non-uniform execution pipelines in an in-order processor are provided. The system includes a first execution unit to perform instruction execution in a first execution pipeline. The system also includes a second execution unit to perform instruction execution in a second execution pipeline, where the second execution pipeline includes a greater number of stages than the first execution pipeline. The system further includes an instruction dispatch unit (IDU), the IDU including OE registers and logic for dispatching an OE-capable instruction to the first execution unit such that the instruction completes execution prior to completing execution of a previously dispatched instruction to the second execution unit. The system additionally includes a latch to hold a result of the execution of the OE-capable instruction until after the second execution unit completes the execution of the previously dispatched instruction.

Abstract: A method for handling cache coherency includes allocating a tag when a cache line is not exclusive in a data cache for a store operation, and sending the tag and an exclusive fetch for the line to coherency logic. An invalidation request is sent within a minimum amount of time to an I-cache, preferably only if it has fetched to the line and has not been invalidated since, which request includes an address to be invalidated, the tag, and an indicator specifying the line is for a PSC operation. The method further includes comparing the request address against stored addresses of prefetched instructions, and in response to a match, sending a match indicator and the tag to an LSU, within a maximum amount of time. The match indicator is timed, relative to exclusive data return, such that the LSU can discard prefetched instructions following execution of the store operation that stores to a line subject to an exclusive data return, and for which the match is indicated.

Abstract: A system, method, and apparatus for enhancing reliability on scan-initialized latches that affect functionality in a digital design are provided. The system includes a group of latches that affect functionality in the digital design based on state values of the latches, where the latches are scan initialized. The system also includes a disable allowance latch (DAL) allocated to the group of latches, where the DAL is a scan-initialized latch. The system further includes a gating function outputting the state value of at least one of the latches in the group to a functional block in the digital design in response to the DAL being in an enabled state and blocking the gating function output in response to the DAL being in a disabled state.

Abstract: A microprocessor equipped to provide hardware initiated prefetching, includes at least one architecture for performing: issuance of a prefetch instruction; writing of a prefetch address into a prefetch fetch address register (PFAR); attempting a prefetch according to the address; detecting one of a cache miss and a cache hit; and if there is a cache miss, then sending a miss request to a next cache level and attempting cache access in a non-busy cycle; and if there is a cache hit, then incrementing the address in the PFAR and completing the prefetch. A method and a computer program product are provided.

Abstract: A system, method and computer program product for sampling computer system performance data are provided. The system includes a sample buffer to store instrumentation data while capturing trace data in a trace array, where the instrumentation data enables measurement of computer system performance. The system further includes a sample interrupt generator to assert a sample interrupt indicating that the instrumentation data is available to read. The sample interrupt is asserted in response to storing the instrumentation data in the sample buffer.

Abstract: A system, method and computer program product for a millicode store access checking instruction are provided. The system includes an operand access control register (OACR) including a test modifier indicator. The system also includes an instruction unit subsystem for fetching and decoding instructions. The instructions include a millicode instruction with an operand defining an address to check for a store access exception. The system further includes an execution unit to execute the millicode instruction. The execution unit performs a method. The method includes receiving the millicode instruction from the instruction unit subsystem, testing for the store access exception at the address as if the test modifier is set absent an update to the OACR, and outputting a result of the testing for the store access exception.

Abstract: A pipelined microprocessor includes circuitry for store forwarding by performing: for each store request, and while a write to one of a cache and a memory is pending; obtaining the most recent value for at least one complete block of data; merging store data from the store request with the complete block of data thus updating the block of data and forming a new most recent value and an updated complete block of data; and buffering the updated complete block of data into a store data queue; for each load request, where the load request may require at least one updated completed block of data: determining if store forwarding is appropriate for the load request on a block-by-block basis; if store forwarding is appropriate, selecting an appropriate block of data from the store data queue on a block-by-block basis; and forwarding the selected block of data to the load request.

Abstract: A system includes a storage device including a human readable common instruction table (CIT) stored as a text file. The system also includes CIT access software for performing a method including receiving a request from a first user for all or a subset of the CIT table relating to logic design and for providing the requested data to the first user. The method also includes receiving a request from a second user is received for all or a subset of the CIT table relating to performance analysis and for providing the requested data to the second user. A request is received from a third user for all or a subset of the CIT data relating to design verification and the requested data is provided to the third user.

Abstract: A pipelined processor includes circuitry adapted for store forwarding, including: for each store request, and while a write to one of a cache and a memory is pending; obtaining the most recent value for at least one block of data; merging store data from the store request with the block of data thus updating the block of data and forming a new most recent value and an updated complete block of data; and buffering the updated block of data into a store data queue; for each additional store request, where the additional store request requires at least one updated block of data: determining if store forwarding is appropriate for the additional store request on a block-by-block basis; if store forwarding is appropriate, selecting an appropriate block of data from the store data queue on a block-by-block basis; and forwarding the selected block of data to the additional store request.

Abstract: A method and system for implementing store buffer allocation for variable length store data operations are provided. The method includes receiving a store address request and at least one store data request and stepping through data operations for each of the store data requests and an address range for the store data requests to determine alignment and data steering information used to select a storage buffer destination for the data in the store data requests. The method further includes determining availability of the storage buffer by maintaining a reservation list for each storage buffer, maintaining a count of the number of available entries for each storage buffer, updating the reservation list to reflect a reservation acceptance for designated available entries, and clearing entries upon completion of the processing of store data operations. The method also includes reserving the selected storage buffer when the number of available entries meets or exceeds the number of entries required for the data.

Abstract: Embodiments of the invention include a method of synchronizing translation changes in a processor including a translation lookaside buffer, the method including setting a control bit to enable blocking of all fetch requests that miss the translation lookaside buffer without changing a translation state of the current process; if there is at least one pending translation, then waiting for completion of the at least one pending translation; and resetting the control bit. A processor and a computer program product are provided.

Abstract: A system and method for avoiding deadlocks when performing storage updates in a multi-processor environment. The system includes a processor having a local cache, a store queue having a temporary buffer with capability to reject exclusive cross-interrogates (XI) while an interrogated cache line is owned exclusive and is to be stored, and a mechanism for performing a method. The method includes setting the processor into a slow mode. A current instruction that includes a data store having one or more target lines is received. The current instruction is executed, with the executing including storing results associated with the data store into the temporary buffer. The store queue is prevented from rejecting an exclusive XI corresponding to the target lines of the current instruction. Each target line is acquired with a status of exclusive ownership, and the contents from the temporary buffer are written to each target line after instruction completion.

Abstract: A method for handling errors in a cache memory without processor core recovery includes receiving a fetch request for data from a processor and simultaneously transmitting fetched data and a parity matching the parity of the fetched data to the processor. The fetched data is received from a higher-level cache into a low level cache of the processor. Upon determining that the fetched data failed an error check indicating that the fetched data is corrupted, the method includes requesting an execution pipeline to discontinue processing and flush its contents, and initiating a clean up sequence, which includes sending an invalidation request to the low level cache causing the low level cache to remove lines associated with the corrupted data, and requesting the execution pipeline to restart. The execution pipeline accesses a copy of the requested data from a higher-level storage location.

Abstract: The invention relates to a method for address translation in a system running multiple levels of virtual machines containing a hierarchically organized translation lookaside buffer comprising at least two linked hierarchical sub-units, a first sub-unit comprising a lookaside buffer for some higher level address translation levels, and the second sub-unit comprising a lookaside buffer for some lower level address translation levels, and said second sub-unit being arranged to store TLB index address information of the upper level sub-unit as tag information in its lower level TLB structure, comprising the steps of collecting intermediate address translation results on different virtual machine levels; and buffering the intermediate translation results in the translation lookaside buffer.

Abstract: Software indicates to hardware of a processing system that its storage modification to a particular cache line is done, and will not be doing any modification for the time being. With this indication, the processor actively releases its exclusive ownership by updating its line ownership from exclusive to read-only (or shared) in its own cache directory and in the storage controller (SC). By actively giving up the exclusive rights, another processor can immediately be given exclusive ownership to that said cache line without waiting on any processor's explicit cross invalidate acknowledgement. This invention also describes the hardware design needed to provide this support.

Abstract: A multiprocessor electronic circuit and an electronic data processing system comprising such circuit are disclosed for reducing the power consumption and the chip area consumption of a multiprocessor system having cryptographic functionality. In one embodiment, the multiprocessor electronic circuit comprises a plurality of processors, a single cryptographic processing unit that comprises a plurality of input/output buffer pairs and two cryptographic engines, a cipher engine and a hash engine, and associated control logic.

Abstract: A method for generating a local clock domain within an operation includes steps of: receiving a clock frequency measurement for a slow portion of logic within the operation; generating a local signal to indicate commencement of the operation and to function as a clock gating signal; latching the clock gating signal to a selected cycle; generating clock domain controls based on the clock gating signal such that the operation times its commencement on the selected cycle; and propagating the clock gating signal in ungated latches for a number of cycles, such that a second operation is restricted from being launched until the operation completes.