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: 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: 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: 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: An approach is provided in which a mapper control unit receives first dispatch information corresponding to a first instruction that identifies a first register and a first register type. The mapper control unit dynamically configures a first history buffer entry to support the first register type and, in turn, stores content from the first register into the first history buffer entry. The mapper control unit then receives second dispatch information corresponding to a second instruction that identifies a second register and a second register type, which is different than the first register type. The mapper control unit dynamically configures a second history buffer entry to support the second register type and, in turn, stores content from the second register into the second history buffer entry.

Abstract: An approach is provided in which a mapper control unit receives dispatch information corresponding to a dispatching instruction that targets some of the register fields in a register. The mapper control unit selects, in a history buffer, an available history buffer entry that includes multiple field sets, each including an itag field. In turn, the mapper control unit modifies some of the history buffer field sets, including the itag fields, based on the existing content stored in the targeted register fields.

Abstract: An approach is provided is provided in which a computing system matches a writeback instruction tag (ITAG) to an entry instruction tag (ITAG) included in an issue queue entry. The writeback ITAG is provided by a first of multiple load store units. The issue queue entry includes multiple ready bits, each of which corresponds to one of the multiple load store units. In response to matching the writeback ITAG to the entry ITAG, the computer system sets a first ready bit corresponding to the first load store unit. In turn, the computing system issues an instruction corresponding to the entry ITAG based upon detecting that each of the multiple ready bits is set.

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: 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: Operation of a multi-slice processor that includes a plurality of execution slices and a plurality of load/store slices coupled via a results bus includes: retrieving, from the results bus into an entry of a register file of an execution slice, speculative result data of a load instruction generated by a load/store slice; and determining, from the load/store slice after expiration of a predetermined period of time, whether the result data is valid.

Abstract: Operation of a multi-slice processor that includes a plurality of execution slices and a plurality of load/store slices coupled via a results bus includes: retrieving, from the results bus into an entry of a register file of an execution slice, speculative result data of a load instruction generated by a load/store slice; and determining, from the load/store slice after expiration of a predetermined period of time, whether the result data is valid.

Abstract: An approach is provided is provided in which a computing system matches a writeback instruction tag (ITAG) to an entry instruction tag (ITAG) included in an issue queue entry. The writeback ITAG is provided by a first of multiple load store units. The issue queue entry includes multiple ready bits, each of which corresponds to one of the multiple load store units. In response to matching the writeback ITAG to the entry ITAG, the computer system sets a first ready bit corresponding to the first load store unit. In turn, the computing system issues an instruction corresponding to the entry ITAG based upon detecting that each of the multiple ready bits is set.

Abstract: Embodiments herein describe a reservation station (RS) in a processor that merges control data from multiple sources into a merged control data value. Before an instruction issues, the RS gathers and saves control data indicating how the instruction is to be executed. This control data may be saved in control registers. An instruction, however, can update many different types of status control bits in these registers. As such, the RS may store different types of control data for an instruction. Instead of the RS containing multiple registers and data paths for every type of control data, the embodiments herein describe merge logic in the RS that permits control data from different sources to be merged into a single control data value. Once the instruction is issued, the RS passes the merged control data value to an execution unit for processing.

Abstract: A hardware execution unit within a processor core executes a second instruction, which is part of a software thread, and which is executed out of order within the software thread. A sticky bit flip detection hardware device detects a change to a sticky bit in a floating-point status and control register (FPSCR) within the processor core. An instruction issue hardware unit identifies a first instruction that is in the software thread that is capable of reading or clearing the sticky bit. A flushing execution unit flushes all results of instructions from an instruction completion table (ICT) that include and are after the first instruction in the software thread. A hardware dispatch device dispatches all instructions that include and are after the first instruction in the software thread for execution by one or more hardware execution units within the processor core in a next-to-complete (NTC) sequential order.

Abstract: A processor core includes an instruction-sequencing unit (ISU). The ISU includes a general register file (GRF) composed of multiple hardware general purpose registers (GPRs), an exception register (XER), and a reservation station (RS). The execution unit(s) load an address of data in a data GPR, and load a first portion of the data in a first data GPR and a second portion of the data in a second data GPR in the GRF, where loading the portions of the data generate intermediate data condition codes that are loaded in the XER. The execution unit(s) generate a cumulative data condition code, which is loaded into a history buffer within the ISU. The intermediate data condition codes are loaded into a reservation station (RS) within the ISU. Upon flushing the GRF and the XER, the ISU repopulates the GRF from a history buffer and the XER from the RS.

Abstract: An approach is provided in which a computing system captures content included in a history buffer entry that corresponds to a flush ITAG. The computing system, in turn, uses an execution unit to transmit the content over a results bus to multiple registers and restore at least one of the registers accordingly.

Abstract: An approach is provided in which a computing system captures content included in a history buffer entry that corresponds to a flush ITAG. The computing system, in turn, uses an execution unit to transmit the content over a results bus to multiple registers and restore at least one of the registers accordingly.

Abstract: Parallel dispatching of multi-operation instructions in a multi-slice computer processor, including: determining whether an instruction must be broken into a plurality of smaller operations; marking each of the smaller operations as instructions to be dispatched in parallel; determining whether each of the operations can be dispatched to distinct instruction issue queues during a same clock cycle; and responsive to determining that each of the operations can be dispatched to distinct instruction issue queues during the same clock cycle, dispatching each of the operations to distinct instruction issue queues during the same clock cycle.

Abstract: Operation of a multi-slice processor that includes execution slices and load/store slices coupled via a results bus includes: receiving, by an execution slice, a producer instruction, including: storing, in an entry of an issue queue, the producer instruction; and storing, in a register, an issue queue entry identifier representing the entry of the issue queue in which the producer instruction is stored; receiving, by the execution slice, a source instruction, the source instruction dependent upon the result of the producer instruction, including: storing, in another entry of the issue queue, the source instruction and the issue queue entry identifier of the producer instruction; determining in dependence upon the issue queue entry identifier of the producer instruction that the producer instruction has issued from the issue queue; and responsive to the determination that the producer instruction has issued from the issue queue, issuing the source instruction from the issue queue.

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.