Abstract: A computer implemented method of processing instructions of a computer program. The method comprises providing at least two copies of program status data; identifying a first update instruction of the instructions that writes to at least one field of the program status data; and associating the first update instruction with a first copy of the at least two copies of program status data.

Abstract: A method, system, and computer program product for reduced overhead address mode change management in a pipelined, recycling microprocessor are provided. The recycling microprocessor includes logic executing thereon. The microprocessor also includes an instruction fetch unit (IFU) supporting computation of address adds in selected address modes and reporting non-equal comparison of the computation to the logic. The microprocessor further includes a fixed point unit determining whether the mode has changed and reporting changes to the logic. Upon determining the comparison yields an equal result but the mode has changed, a recycle event is triggered to ensure subsequent ofetches are relaunched in the correct mode and that no execution writebacks occur from work performed in an incorrect mode.

Abstract: A system and method for collecting instrumentation data in a processor with a pipelined instruction execution stages arranged in an out-of-order execution architecture. One instruction group in a Global Completion Table is marked as a tagged group. Instrumentation data is stored for processing stages processing instructions associated with the tagged group. Sample signal pulses trigger a determination of whether the tagged group is the next-to-complete instruction group. When the sample pulse occurs at a time when the tagged group is the next-to-complete group, the instrumentation data is written as an output. Instrumentation data present during sample pulses that occur when the tagged group is not the next-to-complete group is optionally discarded. Sample pulses are generated at a rate equal to the desired sample rate times the number of groups in the global completion table to better ensure occurrence of a next-to-complete tagged group.

Abstract: A method, processor, and computer program product employing an intermediate register mapper within a register renaming mechanism. A logical register lookup determines whether a hit to a logical register associated with the dispatched instruction has occurred. In this regard, the logical register lookup searches within at least one register mapper from a group of register mappers, including an architected register mapper, a unified main mapper, and an intermediate register mapper. A single hit to the logical register is selected among the group of register mappers. If an instruction having a mapper entry in the unified main mapper has finished but has not completed, the mapping contents of the register mapper entry in the unified main mapper are moved to the intermediate register mapper, and the unified register mapper entry is released, thus increasing a number of unified main mapper entries available for reuse.

Abstract: A system for controlling asynchronous updates to a register, the system including a generally accessible register that is asynchronously updateable by hardware and software. The system also includes protection logic that is in communication with the register. The protection logic includes circuitry to prevent a hardware update to the register from being overwritten by a software update.

Abstract: A multiprocessor chip system having the capability to capture and preserve intermediate machine error state data, wherein the system comprises a second level cache, wherein the second level cache is commonly interfaced with a primary and secondary processing core, and at least two primary error event registers, wherein each primary error event register is logically associated to a respective processing core. Further, at least two secondary error event registers, wherein each secondary error event register is logically associated to a respective processing core, and at least two sub-primary error accumulation registers, wherein each sub-primary error accumulation register is logically associated to a respective primary error event register and a secondary error event register.

Abstract: In operating a dual core processor, a register file collects a history of the error state information for each core. The core error state data can be analyzed to understand the recovery sequence of events. The recorded error sequence over time presents a detailed history of the recovery sequence which is useful to understand complex error scenarios.

Abstract: A computer processing system is provided. The computer processing system includes a first datastore that stores a subset of information associated with an instruction. A first stage of a processor pipeline writes the subset of information to the first datastore based on an execution of an operation associated with the instruction. A second stage of the pipeline initiates reprocessing of the operation associated with the instruction based on the subset of information stored in the first datastore.

Abstract: A method, system, and computer program product for reduced overhead address mode change management in a pipelined, recycling microprocessor are provided. The recycling microprocessor includes logic executing thereon. The microprocessor also includes an instruction fetch unit (IFU) supporting computation of address adds in selected address modes and reporting non-equal comparison of the computation to the logic. The microprocessor further includes a fixed point unit determining whether the mode has changed and reporting changes to the logic. Upon determining the comparison yields an equal result but the mode has changed, a recycle event is triggered to ensure subsequent ofetches are relaunched in the correct mode and that no execution writebacks occur from work performed in an incorrect mode.

Abstract: A method for processor error checking including receiving an instruction data, generating a pre-processing parity data based on the instruction data, maintaining the pre-processing parity data, processing the instruction data, generating a post-processing parity data based on the processed instruction data, checking for an error related to processing the instruction data by comparing the post-processing parity data to the pre-processing parity data, and transmitting an error signal that indicates the error related to processing the instruction data occurred if the post-processing parity data does not match the pre-processing parity data, wherein checking for the error related to processing the instruction data is performed without using a duplicate processing circuitry.

Abstract: Methods and systems for pre-detecting a hardware hang in a processor. The methods comprise maintaining a count of a number of cycles in a predefined time interval without an instruction being completed; detecting a pre-hang condition if said count is within N counts of a hang limit; initiating trace capture in response to detecting said pre-hang condition; and detecting a hang condition if said count equals said hang limit.

Abstract: A system for controlling asynchronous updates to a register, the system including a generally accessible register that is asynchronously updateable by hardware and software. The system also includes protection logic that is in communication with the register. The protection logic includes circuitry to prevent a hardware update to the register from being overwritten by a software update.

Abstract: A multiprocessor chip system having the capability to capture and preserve intermediate machine error state data, wherein the system comprises a second level cache, wherein the second level cache is commonly interfaced with a primary and secondary processing core, and at least two primary error event registers, wherein each primary error event register is logically associated to a respective processing core. Further, at least two secondary error event registers, wherein each secondary error event register is logically associated to a respective processing core, and at least two sub-primary error accumulation registers, wherein each sub-primary error accumulation register is logically associated to a respective primary error event register and a secondary error event register.

Abstract: In operating a dual core processor, a register file collects a history of the error state information for each core. The core error state data can be analyzed to understand the recovery sequence of events. The recorded error sequence over time presents a detailed history of the recovery sequence which is useful to understand complex error scenarios.

Abstract: A system for controlling asynchronous updates to a register, the system including a generally accessible register that is asynchronously updateable by hardware and software. The system also includes protection logic that is in communication with the register. The protection logic includes circuitry to prevent a hardware update to the register from being overwritten by a software update.

Abstract: Disclosed are a method and system for measuring the performance of individual logical partitions of a logically partitioned computer system. Preferably, the method and system both hardware and firmware to allow measurement samples to be collected only for user specified zones of interest. In one embodiment, the method comprises the steps of specifying a Zone or Zones of interest (a Zone being a logical partition), collecting measurement samples only from the one or more specified Zones of interest, and measuring the performance of each of these Zones using only the measurement samples collected from said each of the Zones.

Abstract: Methods and systems for pre-detecting a hardware hang in a processor. The methods comprise maintaining a count of a number of cycles in a predefined time interval without an instruction being completed; detecting a pre-hang condition if said count is within N counts of a hang limit; initiating trace capture in response to detecting said pre-hang condition; and detecting a hang condition if said count equals said hang limit.

Abstract: An embodiment of the invention is a method for capturing hardware trace data. A wrap-back address space is defined and during compression mode, trace data is circularly stored in the wrap-back address space. Upon exiting compression mode, a write address is established for further trace data such that trace data prior to existing compression mode is maintained.

Abstract: A system for controlling asynchronous updates to a register, the system including a generally accessible register that is asynchronously updateable by hardware and software. The system also includes protection logic that is in communication with the register. The protection logic includes circuitry to prevent a hardware update to the register from being overwritten by a software update.

Abstract: A system for controlling asynchronous updates to a register, the system including a generally accessible register that is asynchronously updateable by hardware and software. The system also includes protection logic that is in communication with the register. The protection logic includes circuitry to prevent a hardware update to the register from being overwritten by a software update.