Abstract: Obsoleting values stored in registers in a processor based on processing obsolescent register-encoded instructions is disclosed. The processor is configured to support execution of read and/or write instructions that include obsolescence encoding indicating that one or more of its source and/or target register operands are to be obsoleted by the processor. A register encoded as obsolescent means the data value stored in such register will not be used by subsequent instructions in an instruction stream, and thus does not need to be retained. Thus, such register can be set as being in an obsolescent state so that the data value stored in such register can be ignored to improve performance. As one example, data values for registers having an obsolescent state can be ignored and thus not stored in a saved context for a process being switched out, thus conserving memory and improving processing time for a process switch.

Abstract: A reach matrix scheduler circuit for scheduling instructions to be executed in a processor is disclosed. The scheduler circuit includes an N×R matrix wake-up circuit, where ‘N’ is the instruction window size of the scheduler circuit, and ‘R’ is the “reach” within the instruction window of the matrix wake-up circuit, with ‘R’ being less than ‘N’. A grant line associated with each instruction request entry in the N×R matrix wake-up circuit is coupled to ‘R’ other instruction entries among the ‘N’ instruction entries. When a producer instruction in an instruction request entry is ready for issuance, the grant line associated with the instruction request entry is activated so that any other instruction entries coupled to the grant line (i.e., within the “reach” of the instruction request entry) that consume the produced value generated by the producer instruction are “woken-up” and subsequently indicated as ready to be issued.

Abstract: In certain aspects of the disclosure, an apparatus comprises a first scheduling pool associated with a first minimum scheduling latency and a second scheduling pool associated with a second minimum scheduling latency, the second minimum scheduling latency greater than the first minimum scheduling latency. A common instruction picker is coupled to both the first scheduling pool and the second scheduling pool. The common instruction picker may be configured to select a first instruction from the first scheduling pool and a second instruction from the second scheduling pool, and then choose either the first instruction or second instruction for dispatch according to a picking policy.

Abstract: Various aspects disclosed herein relate to combining instructions to load data from or store data in memory while processing instructions in a computer processor. More particularly, at least one pattern of multiple memory access instructions that reference a common base register and do not fully utilize an available bus width may be identified in a processor pipeline. In response to determining that the multiple memory access instructions target adjacent memory or non-contiguous memory that can fit on a single cache line, the multiple memory access instructions may be replaced within the processor pipeline with one equivalent memory access instruction that utilizes more of the available bus width than either of the replaced memory access instructions.

Abstract: Processors employing memory bypassing in memory data dependent instructions as a store data forwarding mechanism, and related methods. To reduce stalls of memory data dependent, load-based instructions, a memory data dependency detection circuit is configured to detect a memory hazard between a store-based instruction and a load-based instruction based on their opcodes and designation/source operands. Some store-based and load-based instructions have opcodes identifying these instructions as having respective store and load address operand types that can be compared without resolution of their respective store and load addresses. For these detected types of instructions, the memory data dependency detection circuit is configured to determine if a source operand of a load-based instruction matches a target operand of a store-based instruction to detect a memory hazard earlier in the instruction pipeline.

Abstract: Exemplary reach-based explicit dataflow processors and related computer-readable media and methods. The reach-based explicit dataflow processors are configured to support execution of producer instructions encoded with explicit naming of consumer instructions intended to consume the values produced by the producer instructions. The reach-based explicit dataflow processors are configured to make available produced values as inputs to explicitly named consumer instructions as a result of processing producer instructions. The reach-based explicit dataflow processors support execution of a producer instruction that explicitly names a consumer instruction based on using the producer instruction as a relative reference point from the producer instruction.

Abstract: Operand pool instruction reservation clustering in a scheduler circuit in a processor is disclosed. The scheduler circuit includes a plurality of operand pool reservation circuits each having an assigned number of source operands for an instruction stored that must be ready before the instruction is issued. Instructions having the same number of source operands that are not yet ready for its issuance can be stored in an operand pool reservation circuit having the same assigned number of source operands. In this manner, the number of reservation entries and associated comparator circuits in the clustered scheduler circuit is distributed among the plurality of operand pool reservation circuits to avoid or reduce an increase in the number of scheduling path connections and complexity in each reservation circuit. This can avoid or reduce an increase in scheduling latency for a given number of reservation entries in the clustered scheduler circuit.

Abstract: Obsoleting values stored in registers in a processor based on processing obsolescent register-encoded instructions is disclosed. The processor is configured to support execution of read and/or write instructions that include obsolescence encoding indicating that one or more of its source and/or target register operands are to be obsoleted by the processor. A register encoded as obsolescent means the data value stored in such register will not be used by subsequent instructions in an instruction stream, and thus does not need to be retained. Thus, such register can be set as being in an obsolescent state so that the data value stored in such register can be ignored to improve performance. As one example, data values for registers having an obsolescent state can be ignored and thus not stored in a saved context for a process being switched out, thus conserving memory and improving processing time for a process switch.

Abstract: Obsoleting values stored in registers in a processor based on processing obsolescent register-encoded instructions is disclosed. The processor is configured to support execution of read and/or write instructions that include obsolescence encoding indicating that one or more of its source and/or target register operands are to be obsoleted by the processor. A register encoded as obsolescent means the data value stored in such register will not be used by subsequent instructions in an instruction stream, and thus does not need to be retained. Thus, such register can be set as being in an obsolescent state so that the data value stored in such register can be ignored to improve performance. As one example, data values for registers having an obsolescent state can be ignored and thus not stored in a saved context for a process being switched out, thus conserving memory and improving processing time for a process switch.

Abstract: Operand pool instruction reservation clustering in a scheduler circuit in a processor is disclosed. The scheduler circuit includes a plurality of operand pool reservation circuits each having an assigned number of source operands for an instruction stored that must be ready before the instruction is issued. Instructions having the same number of source operands that are not yet ready for its issuance can be stored in an operand pool reservation circuit having the same assigned number of source operands. In this manner, the number of reservation entries and associated comparator circuits in the clustered scheduler circuit is distributed among the plurality of operand pool reservation circuits to avoid or reduce an increase in the number of scheduling path connections and complexity in each reservation circuit. This can avoid or reduce an increase in scheduling latency for a given number of reservation entries in the clustered scheduler circuit.

Abstract: Performing flush recovery using parallel walks of sliced reorder buffers (SROBs) is disclosed herein. In one exemplary embodiment, a register mapping circuit provides a rename mapping table (RMT) comprising RMT entries representing logical register number (LRN) to physical register number (PRN) mappings. The register mapping circuit also provides an SROB comprising multiple SROB slices that each corresponds to a respective LRN. Each SROB slice tracks uncommitted instructions that write to the LRN corresponding to that SROB slice, and maintains those instructions in program order with respect to each other. Upon detecting an uncommitted instruction writing to an LRN, the register mapping circuit allocates an SROB slice entry in the SROB slice corresponding to the LRN. When an pipeline flush from a target instruction occurs, the register mapping circuit restores RMT entries of the RMT to their prior mapping states based on parallel walks of the SROB slices of the SROB.

Abstract: A reach matrix scheduler circuit for scheduling instructions to be executed in a processor is disclosed. The scheduler circuit includes an N×R matrix wake-up circuit, where ‘N’ is the instruction window size of the scheduler circuit, and ‘R’ is the “reach” with the instruction window of matrix wake-up circuit, with ‘R’ being less than ‘N’. A grant line associated with each instruction request entry in the N×R matrix wake-up circuit is coupled to ‘R’ other instruction entries among the ‘N’ instruction entries. When a producer instruction in an instruction request entry is ready for issuance, the grant line associated with the instruction request entry is activated so that any other instruction entries coupled to the grant line (i.e., within the “reach” of the instruction request entry) that consume the produced value generated by the producer instruction are “woken-up” and subsequently indicated as ready to be issued.

Abstract: A register mapping circuit for recovering a register mapping state associated with a flushed instruction by traversing ROB entries from a snapshot of another register mapping state. The register mapping circuit includes a ROB control circuit, a snapshot circuit, and a register rename recovery circuit (RRRC). The ROB control circuit allocates ROB entries to instructions entering a processor pipeline, including a target ROB entry allocated to a target instruction and other ROB entries allocated to other instructions. The snapshot circuit captures snapshots of logical register-to-physical register mapping states in the rename map table in association with a subset of instructions that could be flushed. If the target instruction is flushed, the RRRC restores the rename map table register mapping state corresponding to the target instruction based on a snapshot in a ROB entry allocated to another instruction, and traverses register mapping updates in the intervening ROB entries.

Abstract: A processor element in a processor-based system is configured to fetch one or more instructions associated with a program binary, where the one or more instructions include an instruction having an immediate operand. The processor element is configured to determine if the immediate operand is a reference to a wide immediate operand. In response to determining that the immediate operand is a reference to a wide immediate operand, the processor element is configured to retrieve the wide immediate operand from a common intermediate lookup table (CILT) in the program binary, where the immediate operand indexes the wide immediate operand in the CILT. The processor element is then configured to process the instruction having the immediate operand such that the immediate operand is replaced with the wide immediate operand from the CILT.

Abstract: Obsoleting values stored in registers in a processor based on processing obsolescent register-encoded instructions is disclosed. The processor is configured to support execution of read and/or write instructions that include obsolescence encoding indicating that one or more of its source and/or target register operands are to be obsoleted by the processor. A register encoded as obsolescent means the data value stored in such register will not be used by subsequent instructions in an instruction stream, and thus does not need to be retained. Thus, such register can be set as being in an obsolescent state so that the data value stored in such register can be ignored to improve performance. As one example, data values for registers having an obsolescent state can be ignored and thus not stored in a saved context for a process being switched out, thus conserving memory and improving processing time for a process switch.

Abstract: Latency-based instruction reservation clustering in a scheduler circuit in a processor is disclosed. The scheduler circuit includes a plurality of latency-based reservation circuits each having an assigned producer instruction cycle latency. Producer instructions with the same cycle latency can be clustered in the same latency-based reservation circuit. Thus, the number of reservation entries is distributed among the plurality of latency-based reservation circuits to avoid or reduce an increase in the number of scheduling path connections and complexity in each reservation circuit to avoid or reduce an increase in scheduling latency. The scheduling path connections are reduced for a given number of reservation entries over a non-clustered pick circuit, because signals (e.g., wake-up signals, pick-up signals) used for scheduling instructions in each latency-based reservation circuit do not have to have the same clock cycle latency so as to not impact performance.

Abstract: A processor element in a processor-based system is configured to fetch one or more instructions associated with a program binary, where the one or more instructions include an instruction having an immediate operand. The processor element is configured to determine if the immediate operand is a reference to a wide immediate operand. In response to determining that the immediate operand is a reference to a wide immediate operand, the processor element is configured to retrieve the wide immediate operand from a common intermediate lookup table (CILT) in the program binary, where the immediate operand indexes the wide immediate operand in the CILT. The processor element is then configured to process the instruction having the immediate operand such that the immediate operand is replaced with the wide immediate operand from the CILT.

Abstract: Operand-based reach explicit dataflow processors, and related methods and computer-readable media are disclosed. The operand-based reach explicit dataflow processors support execution of a producer instruction that explicitly names a target consumer operand of a consumer instruction in a consumer operand encoding namespace of the producer instruction. The produced value from execution of the producer instruction is provided or otherwise made available as an input to the named target consumer operand of the consumer instruction as a result of processing the producer instruction. The target consumer operand is encoded in the producer instruction as an operand target distance relative to the producer instruction. Instructions in an instruction stream between the producer instruction and the targeted consumer instruction that have no operands do not consume an operand reach namespace in the producer instructions.

Abstract: Latency-based instruction reservation clustering in a scheduler circuit in a processor is disclosed. The scheduler circuit includes a plurality of latency-based reservation circuits each having an assigned producer instruction cycle latency. Producer instructions with the same cycle latency can be clustered in the same latency-based reservation circuit. Thus, the number of reservation entries is distributed among the plurality of latency-based reservation circuits to avoid or reduce an increase in the number of scheduling path connections and complexity in each reservation circuit to avoid or reduce an increase in scheduling latency. The scheduling path connections are reduced for a given number of reservation entries over a non-clustered pick circuit, because signals (e.g., wake-up signals, pick-up signals) used for scheduling instructions in each latency-based reservation circuit do not have to have the same clock cycle latency so as to not impact performance.

Abstract: Enabling early execution of move-immediate instructions having variable immediate value sizes in processor-based devices is disclosed. In one exemplary embodiment, a processor-based device provides a move-immediate logic circuit that detects a move-immediate instruction comprising an immediate value and a destination register. For frequently encountered immediate values, the move-immediate logic circuit allocates a physical register from an immediate physical register file (IPRF), and writes an IPRF tag corresponding to the allocated IPRF register into a most-recent mapping table (MRT) entry for the destination register. Subsequent move-immediate instructions embedding the same immediate value, as well as other dependent instructions, may then obtain the immediate value from the IPRF register by accessing the MRT entry.