Abstract: A method and apparatus for tracking instructions in a processor. A completion unit in the processor receives an instruction group to add to a table to form a received instruction group. In response to receiving the received instruction group, the completion unit determines whether an entry is present that contains a previously stored instruction group in a first location and has space for storing the received instruction group. In response to the entry being present, the completion unit stores the received instruction group in a second location in the entry to form a stored instruction group.

Abstract: Issue logic identifies a simple fixed point instruction, included in a unified payload, which is ready to issue. The simple fixed point instruction is a type of instruction that is executable by both a fixed point execution unit and a load-store execution unit. In turn, the issue logic determines that the unified payload does not include a load-store instruction that is ready to issue. As a result, the issue logic issues the simple fixed point instruction to the load-store execution unit in response to determining that the simple fixed point instruction is ready to issue and determining that the unified payload does not include a load-store instruction that is ready to issue.

Abstract: A method and apparatus are provided for detecting and handling an instruction flush in a microprocessor system. A flush mechanism is provided that is distributed across all of the execution units in a data processing system. The flush mechanism does not require a central collection point to re-distribute the flush signals to the execution units. Each unit generates a flush vector to all other execution units which is used to block register updates for the flushed instructions.

Abstract: A method, system and processor for improving the performance of an in-order processor. A processor may include an execution unit with an execution pipeline that includes a backup pipeline and a regular pipeline. The backup pipeline may store a copy of the instructions issued to the regular pipeline. The execution pipeline may include logic for allowing instructions to flow from the backup pipeline to the regular pipeline following the flushing of the instructions younger than the exception detected in the regular pipeline. By maintaining a backup copy of the instructions issued to the regular pipeline, instructions may not need to be flushed from separate execution pipelines and re-fetched. As a result, one may complete the results of the execution units to the architected state out of order thereby allowing the completion point to vary among the different execution pipelines.

Abstract: The illustrative embodiments provide a computer implemented method and an apparatus for correcting data errors. An error correction unit receives data from a register. Responsive to receiving the data from the register, the error correction unit determines whether an error is present in the data. Responsive to identifying the error in the data, the error correction unit corrects the data to form corrected data. Responsive to correcting the error in the data, the error correction unit notifies a counter in the register to update.

Abstract: Tracking the order of issued instructions using a counter is presented. In one embodiment, a saturating, decrementing counter is used. The counter is initialized to a value that corresponds to the processor's commit point. Instructions are issued from a first issue queue to one or more execution units and one or more second issue queues. After being issued by the first issue queue, the counter associated with each instruction is decremented during each instruction cycle until the instruction is executed by one of the execution units. Once the counter reaches zero it will be completed by the execution unit. If a flush condition occurs, instructions with counters equal to zero are maintained (i.e., not flushed or invalidated), while other instructions in the pipeline are invalidated based upon their counter values.

Abstract: Power is conserved by dynamically applying clocks to execution units in a pipeline of a microprocessor. A clock to an execution unit is applied only when an instruction to the execution unit is valid. At other times when the execution unit needs not to be operational, the clock is not applied to the execution unit. In a preferred embodiment of the invention, a dynamiclock-control unit is used to provide a control signal to a local clock buffer providing a local clock to an execution unit.

Abstract: A processor includes a general purpose (GP) unit adapted to receive and configured to execute GP instructions; and includes a single instruction multiple data (SIMD) unit adapted to receive and configured to execute SIMD instructions. An instruction unit comprises a first logic unit coupled to the GP unit and a second logic unit coupled to the SIMD unit, wherein SIMD instructions are processed subsequent to GP instructions. In the first logic unit a GP instruction with unresolved dependencies unconditionally causes subsequent SIMD instructions to stall, and an SIMD instruction with unresolved dependencies does not cause subsequent GP instructions to stall. The first logic unit resolves dependencies in GP instructions, provides dependency-free instructions to the GP unit, and provides SIMD instructions to the second logic unit. The second logic unit resolves dependencies in SIMD instructions and provides dependency-free instructions to the SIMD unit.

Abstract: Issue logic identifies a simple fixed point instruction, included in a unified payload, which is ready to issue. The simple fixed point instruction is a type of instruction that is executable by both a fixed point execution unit and a load-store execution unit. In turn, the issue logic determines that the unified payload does not include a load-store instruction that is ready to issue. As a result, the issue logic issues the simple fixed point instruction to the load-store execution unit in response to determining that the simple fixed point instruction is ready to issue and determining that the unified payload does not include a load-store instruction that is ready to issue.

Abstract: A method and apparatus for register renaming are provides in the illustrative embodiments. A mapper receives a request for a data in a logical register. The mapper searches an in-flight map table and a set of architected map tables for the data in the logical register. The mapper identifies an entry in one of the in-flight map table and an architected map table in the set of architected map tables that corresponds with the logical register in the request. The mapper returns a location of a physical register, which holds the requested data.

Abstract: Dynamic power management in a processor design is presented. A pipeline stage's stall detection logic detects a stall condition, and sends a signal to idle detection logic to gate off the pipeline's register clocks. The stall detection logic also monitors a downstream pipeline stage's stall condition, and instructs the idle detection logic to gate off the pipeline stage's registers when the downstream pipeline stage is in a stall condition as well. In addition, when the pipeline stage's stall detection logic detects a stall condition, either from the downstream pipeline stage or from its own pipeline units, the pipeline stage's stall detection logic informs an upstream pipeline stage to gate off its clocks and thus, conserve more power.

Abstract: A method, system and processor for improving the performance of an in-order processor. A processor may include an execution unit with an execution pipeline that includes a backup pipeline and a regular pipeline. The backup pipeline may store a copy of the instructions issued to the regular pipeline. The execution pipeline may include logic for allowing instructions to flow from the backup pipeline to the regular pipeline following the flushing of the instructions younger than the exception detected in the regular pipeline. By maintaining a backup copy of the instructions issued to the regular pipeline, instructions may not need to be flushed from separate execution pipelines and re-fetched. As a result, one may complete the results of the execution units to the architected state out of order thereby allowing the completion point to vary among the different execution pipelines.

Abstract: Tracking the order of issued instructions using a counter is presented. In one embodiment, a saturating, decrementing counter is used. The counter is initialized to a value that corresponds to the processor's commit point. Instructions are issued from a first issue queue to one or more execution units and one or more second issue queues. After being issued by the first issue queue, the counter associated with each instruction is decremented during each instruction cycle until the instruction is executed by one of the execution units. Once the counter reaches zero it will be completed by the execution unit. If a flush condition occurs, instructions with counters equal to zero are maintained (i.e., not flushed or invalidated), while other instructions in the pipeline are invalidated based upon their counter values.

Abstract: Power is conserved by dynamically applying clocks to execution units in a pipeline of a microprocessor. A clock to an execution unit is applied only when an instruction to the execution unit is valid. At other times when the execution unit needs not to be operational, the clock is not applied to the execution unit. In a preferred embodiment of the invention, a dynamic clock-control unit is used to provide a control signal to a local clock buffer providing a local clock to an execution unit.

Abstract: Tracking the order of issued instructions using a counter is presented. In one embodiment, a saturating, decrementing counter is used. The counter is initialized to a value that corresponds to the processor's commit point. Instructions are issued from a first issue queue to one or more execution units and one or more second issue queues. After being issued by the first issue queue, the counter associated with each instruction is decremented during each instruction cycle until the instruction is executed by one of the execution units. Once the counter reaches zero it will be completed by the execution unit. If a flush condition occurs, instructions with counters equal to zero are maintained (i.e., not flushed or invalidated), while other instructions in the pipeline are invalidated based upon their counter values.

Abstract: A method, system and processor for improving the performance of an in-order processor. A processor may include an execution unit with an execution pipeline that includes a backup pipeline and a regular pipeline. The backup pipeline may store a copy of the instructions issued to the regular pipeline. The execution pipeline may include logic for allowing instructions to flow from the backup pipeline to the regular pipeline following the flushing of the instructions younger than the exception detected in the regular pipeline. By maintaining a backup copy of the instructions issued to the regular pipeline, instructions may not need to be flushed from separate execution pipelines and re-fetched. As a result, one may complete the results of the execution units to the architected state out of order thereby allowing the completion point to vary among the different execution pipelines.

Abstract: Power is conserved by dynamically applying clocks to execution units in a pipeline of a microprocessor. A clock to an execution unit is applied only when an instruction to the execution unit is valid. At other times when the execution unit needs not to be operational, the clock is not applied to the execution unit. In a preferred embodiment of the invention, a dynamic clock-control unit is used to provide a control signal to a local clock buffer providing a local clock to an execution unit.

Abstract: A method and apparatus for register renaming are provides in the illustrative embodiments. A mapper receives a request for a data in a logical register. The mapper searches an in-flight map table and a set of architected map tables for the data in the logical register. The mapper identifies an entry in one of the in-flight map table and an architected map table in the set of architected map tables that corresponds with the logical register in the request. The mapper returns a location of a physical register, which holds the requested data.

Abstract: Dynamic power management in a processor design is presented. A pipeline stage's stall detection logic detects a stall condition, and sends a signal to idle detection logic to gate off the pipeline's register clocks. The stall detection logic also monitors a downstream pipeline stage's stall condition, and instructs the idle detection logic to gate off the pipeline stage's registers when the downstream pipeline stage is in a stall condition as well. In addition, when the pipeline stage's stall detection logic detects a stall condition, either from the downstream pipeline stage or from its own pipeline units, the pipeline stage's stall detection logic informs an upstream pipeline stage to gate off its clocks and thus, conserve more power.

Abstract: A pipeline stage's stall detection logic detects a stall condition, and sends a signal to idle detection logic to gate off the pipeline's register clocks. The stall detection logic also monitors a downstream pipeline stage's stall condition, and instructs the idle detection logic to gate off the pipeline stage's registers when the downstream pipeline stage is in a stall condition as well. In addition, when the pipeline stage's stall detection logic detects a stall condition, either from the downstream pipeline stage or from its own pipeline units, the pipeline stage's stall detection logic informs an upstream pipeline stage to gate off its clocks and thus, conserve more power.