Abstract: Embodiments described herein include a computing system that permits partial writes into a memory element—e.g., a register on a processor. For example, the data to be written into the memory element may be spread across multiple sources. The register may receive data from two different sources at different times and perform two separate partial write commands to store the data. Embodiments herein generate an ECC value for each of the partial writes. That is, when storing the data of the first partial write, the computing system generates a first ECC value for the data in the first partial write and stores this value in the memory element. Later, when performing the second partial write, the computing system generates a second ECC value for this data which is also stored in the memory element.

Abstract: A system and process for managing thread transitions includes providing two data register sets coupled to a processor and using, by the processor, the two register sets as first-level registers for thread execution. A determination is made whether a quantity of the first-level registers needed to execute one or more threads exceeds a quantity of the first-level registers of the two data register sets. Responsive to determining that the quantity of the first-level registers needed to execute the one or more threads exceeds the quantity of the first-level registers of the two data register sets, a portion of main memory or cache memory is assigned as second-level registers where the second-level registers serve as registers of at least one of the two data register sets for executing the one or more threads.

Abstract: Operation of a multi-slice processor including execution slices and load/store slices, where the load/store slices are coupled to the execution slices via a results bus and the results bus includes segments assigned to carry results of a different instruction type, includes: receiving a producer instruction that includes an identifier of an instruction type and an identifier of the producer instruction, including storing the identifier of the instruction type and the identifier of the producer instruction in an entry of a register; receiving a source instruction dependent upon the result of the producer instruction including storing, in an issue queue, the source instruction, the identifier of the instruction type of the producer instruction, and an identifier of the producer instruction; and snooping the identifier of the producer instruction only from the segment of the results bus assigned to carry results of the instruction type of the producer instruction.

Abstract: Embodiments include systems, methods, and computer program products for on-demand error detection and correction of registers in a processor. One method includes detecting, before a first instruction is dispatched to an issue queue in the processor, an error in data, associated with the first instruction, stored in an entry of a register file in the processor. The method also includes, after detecting the error, halting the dispatch of the first instruction to the issue queue, and determining whether the entry of the register file has completed. The method further includes determining whether to perform error correction on the register file based on the determination of whether the entry of the register file has completed.

Abstract: Embodiments include systems, methods, and computer program products for using a multi-level history buffer (HB) for a speculative transaction. One method includes after dispatching a first instruction indicating start of the speculative transaction, marking one or more register file (RF) entries as pre-transaction memory (PTM), and after dispatching a second instruction targeting one of the marked RF entries, moving data from the marked RF entry to a first level HB entry and marking the first level HB entry as PTM. The method also includes upon detecting a write back to the first level HB entry, moving data from the first level HB entry to a second level HB entry and marking the second level HB entry as PTM. The method further includes upon determining that the second level HB entry has been completed, moving data from the second level HB entry to a third level HB entry.

Abstract: Operation of a multi-slice processor that includes a plurality of execution slices and a plurality of load/store slices, where the load/store slices are coupled to the execution slices via a results bus. Operation of such a multi-slice processor includes: capturing first state information corresponding to a first set of control signals; monitoring state information of a plurality of logical components of the multi-slice processor; selecting, in dependence upon one or more selection criteria and upon the monitored state information, a second set of control signals; and capturing second state information corresponding to the second set of control signals, wherein the first set of control signals is different than the second set of control signals.

Abstract: Operation of a multi-slice processor including execution slices and load/store slices, where the load/store slices are coupled to the execution slices via a results bus and the results bus includes segments assigned to carry results of a different instruction type, includes: receiving a producer instruction that includes an identifier of an instruction type and an identifier of the producer instruction, including storing the identifier of the instruction type and the identifier of the producer instruction in an entry of a register; receiving a source instruction dependent upon the result of the producer instruction including storing, in an issue queue, the source instruction, the identifier of the instruction type of the producer instruction, and an identifier of the producer instruction; and snooping the identifier of the producer instruction only from the segment of the results bus assigned to carry results of the instruction type of the producer instruction.

Abstract: Fast issuance and execution of a multi-width instruction across multiple slices in a parallel slice processor core is supported in part through the use of an early notification signal passed between issue logic associated with multiple slices handling that multi-width instruction coupled with an issuance of a different instruction by the originating issue logic for the early notification signal.

Abstract: An approach is provided in which a mapper control unit matches a result instruction tag corresponding to an executed instruction to a history buffer entry's instruction tag. The matched history buffer entry includes multiple history buffer field sets that each include a field set state indicator. The mapper control unit identifies a subset of the history buffer field sets having a valid field set state indicator and stores result data corresponding to the result instruction tag in the identified subset of history buffer field sets. In turn, the mapper control unit restores a subset of a register's fields utilizing content from the subset of history buffer field sets.

Abstract: Handling unaligned load operations, including: receiving a request to load data stored within a range of addresses; determining that the range of addresses includes addresses associated with a plurality of caches, wherein each of the plurality of caches are associated with a distinct processor slice; issuing, to each distinct processor slice, a request to load data stored within a cache associated with the distinct processor slice, wherein the request to load data stored within the cache associated with the distinct processor slice includes a portion of the range of addresses; executing, by each distinct processor slice, the request to load data stored within the cache associated with the distinct processor slice; and receiving, over a plurality of data communications busses, execution results from each distinct processor slice, wherein each data communications busses is associated with one of the distinct processor slices.

Abstract: Handling unaligned load operations, including: receiving a request to load data stored within a range of addresses; determining that the range of addresses includes addresses associated with a plurality of caches, wherein each of the plurality of caches are associated with a distinct processor slice; issuing, to each distinct processor slice, a request to load data stored within a cache associated with the distinct processor slice, wherein the request to load data stored within the cache associated with the distinct processor slice includes a portion of the range of addresses; executing, by each distinct processor slice, the request to load data stored within the cache associated with the distinct processor slice; and receiving, over a plurality of data communications busses, execution results from each distinct processor slice, wherein each data communications busses is associated with one of the distinct processor slices.

Abstract: Supplemental instruction dispatch may be used in some instances in a parallel slice processor to dispatch additional instructions, referred to as supplemental instructions, to supplemental instruction ports of execution slices and using primary instruction ports of one or more execution slices to supply one or more source operands for such supplemental instructions. In addition, in some instances, in lieu of or in addition to supplemental instruction dispatch, selective slice partitioning may be used to selectively partition groups of execution slices in a parallel slice processor based upon a threading mode within which such execution slices are executing.

Abstract: Techniques are disclosed for back-to-back issue of instructions in a processor. A first instruction is stored in a queue position in an issue queue. The issue queue stores instructions in a corresponding queue position. The first instruction includes a target instruction tag and at least a source instruction tag. The target instruction tag is stored in a table storing a plurality of target instruction tags associated with a corresponding instruction. Each stored target instruction tag specifies a logical register that stores a target operand. Upon determining, based on the source instruction tag associated with the first instruction and the target instruction tag associated with a second instruction, that the first instruction is dependent on the second instruction, a pointer to the first instruction is associated with the second instruction. The pointer is used to wake up the first instruction upon issue of the second instruction.

Abstract: Method and system for writing a history buffer in a processing unit is provided. At least a first instruction and a second instruction are dispatched in a single processing cycle, targeting a same register file entry. The processing unit includes two or more processing slices, each processing slice comprising a corresponding history buffer and at least a portion of a register file. Upon determining that first result data corresponding to the first instruction is older than second result data corresponding to the second instruction, the first result data is written into a history buffer bypassing the register file entry, in response to the determination. Further, the second result data is written into the register file entry.

Abstract: Handling unaligned load operations, including: receiving a request to load data stored within a range of addresses; determining that the range of addresses includes addresses associated with a plurality of caches, wherein each of the plurality of caches are associated with a distinct processor slice; issuing, to each distinct processor slice, a request to load data stored within a cache associated with the distinct processor slice, wherein the request to load data stored within the cache associated with the distinct processor slice includes a portion of the range of addresses; executing, by each distinct processor slice, the request to load data stored within the cache associated with the distinct processor slice; and receiving, over a plurality of data communications busses, execution results from each distinct processor slice, wherein each data communications busses is associated with one of the distinct processor slices.

Abstract: Handling unaligned load operations, including: receiving a request to load data stored within a range of addresses; determining that the range of addresses includes addresses associated with a plurality of caches, wherein each of the plurality of caches are associated with a distinct processor slice; issuing, to each distinct processor slice, a request to load data stored within a cache associated with the distinct processor slice, wherein the request to load data stored within the cache associated with the distinct processor slice includes a portion of the range of addresses; executing, by each distinct processor slice, the request to load data stored within the cache associated with the distinct processor slice; and receiving, over a plurality of data communications busses, execution results from each distinct processor slice, wherein each data communications busses is associated with one of the distinct processor slices.

Abstract: An approach is provided in which a mapper control unit receives dispatch information corresponding to an instruction that targets a first field in a first register and a second field in a second register, the first register being a first register type and the second register being a second register type. As such, the mapper control unit selects a history buffer entry in a history buffer that is adapted to concurrently store content corresponding to the first register type and the second register type. In turn, the mapper control unit stores first content from the first register's targeted first fields and second content from the second register's targeted second fields into the selected history buffer entry.

Abstract: Mechanisms are provided, in a processor, for executing instructions that are younger than a previously dispatched synchronization (sync) instruction is provided. An instruction sequencer unit of the processor dispatches a sync instruction. The sync instruction is sent to a nest of one or more devices outside of the processor. The instruction sequencer unit dispatches a subsequent instruction after dispatching the sync instruction. The dispatching of the subsequent instruction after dispatching the sync instruction is performed prior to receiving a sync acknowledgement response from the nest. The instruction sequencer unit performs a completion of the subsequent instruction based on whether completion of the subsequent instruction is dependent upon receiving the sync acknowledgement from the nest and completion of the sync instruction.

Abstract: A system and process for managing thread transitions includes determining that a transition is to be made regarding the relative use of two data register sets where the two data register sets are used by a processor as first-level registers for thread execution. Based on the transition determination, a determination is made whether to move thread data in at least one of the first-level registers to second-level registers. Responsive to determining to move the thread data, a portion of main memory or cache memory is assigned as the second-level registers where the second-level registers serve as registers of at least one of the two data register sets for executing a thread. The thread data from the at least one first-level register is moved to the second-level registers based on the move determination.

Abstract: Operation of a multi-slice processor including execution slices and load/store slices, where the load/store slices are coupled to the execution slices via a results bus and the results bus includes segments assigned to carry results of a different instruction type, includes: receiving a producer instruction that includes an identifier of an instruction type and an identifier of the producer instruction, including storing the identifier of the instruction type and the identifier of the producer instruction in an entry of a register; receiving a source instruction dependent upon the result of the producer instruction including storing, in an issue queue, the source instruction, the identifier of the instruction type of the producer instruction, and an identifier of the producer instruction; and snooping the identifier of the producer instruction only from the segment of the results bus assigned to carry results of the instruction type of the producer instruction.