Abstract: Processor-guided execution of offloaded instructions using fixed function operations is disclosed. Instructions designated for remote execution by a target device are received by a processor. Each instruction includes, as an operand, a target register in the target device. The target register may be an architected virtual register. For each of the plurality of instructions, the processor transmits an offload request in the order that the instructions are received. The offload request includes the instruction designated for remote execution. The target device may be, for example, a processing-in-memory device or an accelerator coupled to a memory.

Abstract: The invention relates to a system (10) for imaging a body (11) of a person. The system (1) comprises a sensor unit (12) configured to capture first imaging data of the body, wherein the sensor unit (12) comprises an optical camera and/or an infrared camera and/or an acoustic imaging sensor; an electromagnetic, EM, wave scanner (14) configured to capture second imaging data of the body, wherein the EM wave scanner comprises a plurality of antennas (15) which are configured to transmit EM radiation in a mm and/or cm range towards the body (11), and to receive a reflection of said EM radiation from the body (11); and a processing unit (16) which is configured to process the first imaging data and the second imaging data and to generate a three-dimensional image (33) of the body (11) based on said processing.

Abstract: Processor-guided execution of offloaded instructions using fixed function operations is disclosed. Instructions designated for remote execution by a target device are received by a processor. Each instruction includes, as an operand, a target register in the target device. The target register may be an architected virtual register. For each of the plurality of instructions, the processor transmits an offload request in the order that the instructions are received. The offload request includes the instruction designated for remote execution. The target device may be, for example, a processing-in-memory device or an accelerator coupled to a memory.

Abstract: A processing system includes a branch prediction structure storing information used to predict the outcome of a branch instruction. The processing system also includes a register storing a first identifier of a first process in response to the processing system changing from a first mode that allows the first process to modify the branch prediction structure to a second mode in which the branch prediction structure is not modifiable. The processing system further includes a processor core that selectively flushes the branch prediction structure based on a comparison of a second identifier of a second process and the first identifier stored in the register. The comparison is performed in response to the second process causing a change from the second mode to the first mode.

Abstract: A processor core executes a first process. The first process is associated with a first context tag that is generated based on context information controlled by an operating system or hypervisor of the processing system. A branch prediction structure selectively provides the processor core with access to an entry in the branch prediction structure based on the first context tag and a second context tag associated with the entry. The branch prediction structure selectively provides the processor core with access to the entry in response to the first process executing a branch instruction. Tagging entries in the branch prediction structure reduces, or eliminates, aliasing between information used to predict branches taken by different processes at a branch instruction.

Abstract: A processor core associated with a first cache initiates entry into a powered-down state. In response, information representing a set of entries of the first cache are stored in a retention region that receives a retention voltage while the processor core is in a powered-down state. Information indicating one or more invalidated entries of the set of entries is also stored in the retention region. In response to the processor core initiating exit from the powered-down state, entries of the first cache are restored using the stored information representing the entries and the stored information indicating the at least one invalidated entry.

Abstract: Techniques for controlling prefetching of instructions into an instruction cache are provided. The techniques include tracking either or both of branch target buffer misses and instruction cache misses, modifying a throttle toggle based on the tracking, and adjusting prefetch activity based on the throttle toggle.

Abstract: A set of entries in a branch prediction structure for a set of second blocks are accessed based on a first address of a first block. The set of second blocks correspond to outcomes of one or more first branch instructions in the first block. Speculative prediction of outcomes of second branch instructions in the second blocks is initiated based on the entries in the branch prediction structure. State associated with the speculative prediction is selectively flushed based on types of the branch instructions. In some cases, the branch predictor can be accessed using an address of a previous block or a current block. State associated with the speculative prediction is selectively flushed from the ahead branch prediction, and prediction of outcomes of branch instructions in one of the second blocks is selectively initiated using non-ahead accessing, based on the types of the one or more branch instructions.

Abstract: Processor-guided execution of offloaded instructions using fixed function operations is disclosed. Instructions designated for remote execution by a target device are received by a processor. Each instruction includes, as an operand, a target register in the target device. The target register may be an architected virtual register. For each of the plurality of instructions, the processor transmits an offload request in the order that the instructions are received. The offload request includes the instruction designated for remote execution. The target device may be, for example, a processing-in-memory device or an accelerator coupled to a memory.

Abstract: Systems, apparatuses, and methods for implementing scheduler queue assignment burst mode are disclosed. A scheduler queue assignment unit receives a dispatch packet with a plurality of operations from a decode unit in each clock cycle. The scheduler queue assignment unit determines if the number of operations in the dispatch packet for any class of operations is greater than a corresponding threshold for dispatching to the scheduler queues in a single cycle. If the number of operations for a given class is greater than the corresponding threshold, and if a burst mode counter is less than a burst mode window threshold, the scheduler queue assignment unit dispatches the extra number of operations for the given class in a single cycle. By operating in burst mode for a given operation class during a small number of cycles, processor throughput can be increased without starving the processor of other operation classes.

Abstract: A processor predicts a number of loop iterations associated with a set of loop instructions. In response to the predicted number of loop iterations exceeding a first loop iteration threshold, the set of loop instructions are executed in a loop mode that includes placing at least one component of an instruction pipeline of the processor in a low-power mode or state and executing the set of loop instructions from a loop buffer. In response to the predicted number of loop iterations being less than or equal to a second loop iteration threshold, the set of instructions are executed in a non-loop mode that includes maintaining at least one component of the instruction pipeline in a powered up state and executing the set of loop instructions from an instruction fetch unit of the instruction pipeline.

Abstract: Merging branch target buffer entries includes maintaining, in a branch target buffer, an entry corresponding to first branch instruction, where the entry identifies a first branch target address for the first branch instruction and a second branch target address for a second branch instruction; and accessing, based on the first branch instruction, the entry.

Abstract: A processor includes a branch target buffer (BTB) having a plurality of entries whereby each entry corresponds to an associated instruction pointer value that is predicted to be a branch instruction. Each BTB entry stores a predicted branch target address for the branch instruction, and further stores information indicating whether the next branch in the block of instructions associated with the predicted branch target address is predicted to be a return instruction. In response to the BTB indicating that the next branch is predicted to be a return instruction, the processor initiates an access to a return stack that stores the return address for the predicted return instruction. By initiating access to the return stack responsive to the return prediction stored at the BTB, the processor reduces the delay in identifying the return address, thereby improving processing efficiency.

Abstract: A system and method for tracking stores and loads to reduce load latency when forming the same memory address by bypassing a load store unit within an execution unit is disclosed. Store-load pairs which have a strong history of store-to-load forwarding are identified. Once identified, the load is memory renamed to the register stored by the store. The memory dependency predictor may also be used to detect loads that are dependent on a store but cannot be renamed. In such a configuration, the dependence is signaled to the load store unit and the load store unit uses the information to issue the load after the identified store has its physical address.

Abstract: A processor predicts a number of loop iterations associated with a set of loop instructions. In response to the predicted number of loop iterations exceeding a first loop iteration threshold, the set of loop instructions are executed in a loop mode that includes placing at least one component of an instruction pipeline of the processor in a low-power mode or state and executing the set of loop instructions from a loop buffer. In response to the predicted number of loop iterations being less than or equal to a second loop iteration threshold, the set of instructions are executed in a non-loop mode that includes maintaining at least one component of the instruction pipeline in a powered up state and executing the set of loop instructions from an instruction fetch unit of the instruction pipeline.

Abstract: Systems, apparatuses, and methods for implementing scheduler queue assignment burst mode are disclosed. A scheduler queue assignment unit receives a dispatch packet with a plurality of operations from a decode unit in each clock cycle. The scheduler queue assignment unit determines if the number of operations in the dispatch packet for any class of operations is greater than a corresponding threshold for dispatching to the scheduler queues in a single cycle. If the number of operations for a given class is greater than the corresponding threshold, and if a burst mode counter is less than a burst mode window threshold, the scheduler queue assignment unit dispatches the extra number of operations for the given class in a single cycle. By operating in burst mode for a given operation class during a small number of cycles, processor throughput can be increased without starving the processor of other operation classes.

Abstract: Techniques for controlling prefetching of instructions into an instruction cache are provided. The techniques include tracking either or both of branch target buffer misses and instruction cache misses, modifying a throttle toggle based on the tracking, and adjusting prefetch activity based on the throttle toggle.

Abstract: A subset of a set of architectural registers in a processing system is marked (or “tainted”) to indicate that speculative use of data in the subset of the architectural registers is constrained based on a taint handling policy. One or more speculation features supported by the processing system are disabled for the instruction so that the one or more speculation features cannot be used on data in the subset. In some cases, values of bits associated with the subset of architectural registers are modified to indicate that the subset is tainted. The taint handling policy can be indicated by values stored in a policy register. Taint markings are tracked in response to values stored in the tainted architectural registers being written to a memory or read from the memory.

Abstract: A processor core associated with a first cache initiates entry into a powered-down state. In response, information representing a set of entries of the first cache are stored in a retention region that receives a retention voltage while the processor core is in a powered-down state. Information indicating one or more invalidated entries of the set of entries is also stored in the retention region. In response to the processor core initiating exit from the powered-down state, entries of the first cache are restored using the stored information representing the entries and the stored information indicating the at least one invalidated entry.

Abstract: A processor and method for handling lock instructions identifies which of a plurality of older store instructions relative to a current lock instruction are able to be locked. The method and processor lock the identified older store instructions as an atomic group with the current lock instruction. The method and processor negatively acknowledge probes until all of the older store instructions in the atomic group have written to cache memory. In some implementations, an atomic grouping unit issues an indication to lock identified older store instructions that are retired and lockable, and in some implementations, also issues an indication to lock older stores that are determined to be lockable that are non-retired.