Abstract: A data processing system 2 is provided with branch prediction circuitry 20 for performing branch prediction operations. Next branch table circuitry 22 stores data identifying from a given branch instruction what will be the address of the next branch instruction to be encountered within the program flow. This next branch instruction address is supplied to the branch prediction circuitry 20 which uses it to form its prediction prior to that next branch instruction being identified as such by the instruction decoder 16. This permits branch prediction to commence earlier in the branch prediction circuitry 20 than would otherwise be the case.

Abstract: An ISA-defined instruction includes an immediate field having a first and second portions specifying first and second values, which instructs the microprocessor to perform an operation using a constant value as one of its source operands. The constant value is the first value rotated/shifted by a number of bits based on the second value. An instruction translator translates the instruction into one or more microinstructions. An execution pipeline executes the microinstructions generated by the instruction translator. The instruction translator, rather than the execution pipeline, generates the constant value for the execution pipeline as a source operand of at least one of the microinstructions for execution by the execution pipeline.

Abstract: A method and circuit arrangement utilize a programmable microcode unit that is capable of being programmed via software to modify the instruction sequences output by the microcode unit in response to microcode instructions issued to the microcode unit. Multiple instruction sequences may be stored in different partitions defined in one or more rewriteable memories such that different instruction sequences may be output for different instances of a microcode instruction executing in different, concurrently-executing instruction streams.

Abstract: A method for suppressing prediction of a backward branch instruction used in a vector partitioning loop includes detecting the first backward branch instruction that occurs after a predicate generating instruction. The predicate generating instruction generates a predicate vector that is dependent upon a dependency vector where each element of the dependency vector indicates whether a data dependency exists between elements of a vector instruction. The method also includes receiving an indication of a prediction accuracy of a prediction of the backward branch instruction. If the prediction accuracy does not satisfy a threshold value, the prediction of the backward branch instruction is suppressed until the dependency vector on which the predicate-generating instruction depends is available.

Abstract: An apparatus includes an instruction decoder, first and second source registers and a circuit coupled to the decoder to receive packed data from the source registers and to unpack the packed data responsive to an unpack instruction received by the decoder. A first packed data element and a third packed data element are received from the first source register. A second packed data element and a fourth packed data element are received from the second source register. The circuit copies the packed data elements into a destination register resulting with the second packed data element adjacent to the first packed data element, the third packed data element adjacent to the second packed data element, and the fourth packed data element adjacent to the third packed data element.

Abstract: For efficient issue of a superscalar instruction a circuit is employed which retrieves an instruction of each instruction code type other than a prefix based on a determination result of decoders for determining instruction code type, adds the immediately preceding instruction to the retrieved instruction, and outputs the resultant. When an instruction of a target code type is detected in a plurality of instruction units to be searched, the circuit outputs the detected instruction code and the immediately preceding instruction other than the target code type as prefix code candidates. When an instruction of a target code type cannot be detected at the rear end of the instruction units, the circuit outputs the instruction at the rear end as a prefix code candidate. When an instruction of a target code type is detected at the head in the instruction code search, the circuit outputs the instruction code at the head.

Abstract: In the various aspects, a virtual machine operating at the machine layer may use power consumption models to partition object code into portions, identify the relative power efficiencies of the mobile device processors for the various code portions, and route the code portions to the mobile device processors that can perform the operations using the least amount of energy. A dynamic binary translator process may translate the object code portions into an instruction set language supported by the hardware component identified as being preferred. The code portions may be executed and the amount of power consumed may be measured, with the measurements used to generate and/or update performance and power consumption models.

Abstract: A processor includes an execution unit to execute instructions, where each operand of each executed instruction has one or more elements of an element size and at least one operand of the instruction corresponds to a register of a register size. The processor further includes a counter configured to count a number of instructions that have been executed by the execution unit associated with a particular combination of register size and element size.

Abstract: Techniques are disclosed relating to integrated circuits that include hardware support for divide and/or square root operations. In one embodiment, an integrated circuit is disclosed that includes a division unit that, in turn, includes a normalization circuit and a plurality of divide engines. The normalization circuit is configured to normalize a set of operands. Each divide engine is configured to operate on a respective normalized set of operands received from the normalization circuit. In some embodiments, the integrated circuit includes a scheduler unit configured to select instructions for issuance to a plurality of execution units including the division unit. The scheduler unit is further configured to maintain a counter indicative of a number of instructions currently being operated on by the division unit, and to determine, based on the counter whether to schedule subsequent instructions for issuance to the division unit.

Abstract: The invention relates to an electronic device for data processing, which includes an execution unit with a temporary register, a register file, a first feedback path from the data output of the execution unit to the register file, a second feedback path from the data output of the execution unit to the temporary register, a switch configured to connect the first feedback path and/or the second feedback path, and a logic stage coupled to control the switch. The control stage is configured to control the switch to connect the second feedback path if the data output of an execution unit is used as an operand in the subsequent operation of an execution unit.

Abstract: A data processing apparatus having processing circuitry, a scalar register bank and a vector register bank, including decoding circuitry arranged to decode a sequence of instructions to generate control signals for the processing circuitry. The decoding circuitry is responsive to a decode modifier instruction within the sequence of instructions to alter decoding of a subsequent scalar instruction in the sequence by mapping at least one scalar operand specified by the subsequent scalar instruction to at least one vector operand in the vector register bank, and, in dependence on the scalar operation specified by the subsequent scalar instruction, determining a vector operation to be performed on at least a subset of the operand elements within the at least the one vector operand. Such an approach enables a wide variety of vector operations to be specified without the need to individually define separate vector instructions for those vector operations.

Abstract: A data processing apparatus executes instructions in a sequence of pipelined execution stages. An error detection unit twice samples a signal associated with execution of an instruction and generates an error signal if the samples differ. An exception storage unit maintains an age-ordered list of entries corresponding to instructions issued to the execution pipeline and can mark an entry to show if the error signal has been generated in association with that instruction. A timer unit is responsive to generation of the error signal to initiate timing of a predetermined time period. An error recovery unit initiates a soft pipeline flush procedure if an oldest pending entry in the list has said error marker stored in association therewith and initiates a hard pipeline flush procedure if said predetermined time period elapses, said hard flush procedure comprising resetting said pipeline to a predetermined state.

Abstract: An external Auxiliary Execution Unit (AXU) interface is provided between a processing core disposed in a first programmable chip and an off-chip AXU disposed in a second programmable chip to integrate the AXU with an issue unit, a fixed point execution unit, and optionally other functional units in the processing core. The external AXU interface enables the issue unit to issue instructions to the AXU in much the same manner as the issue unit would be able to issue instructions to an AXU that was disposed on the same chip. By doing so, the AXU on the second programmable chip can be designed, tested and verified independent of the processing core on the first programmable chip, thereby enabling a common processing core, which has been designed, tested, and verified, to be used in connection with multiple different AXU designs.

Abstract: In a multiprocessor system, a primary processor may store an executable image for a secondary processor. A communication protocol assists the transfer of an image header and data segment(s) of the executable image from the primary processor to the secondary processor. Messages between the primary processor and secondary processor indicate successful receipt of transferred data, termination of a transfer process, and acknowledgement of same.

Abstract: A processor has a register file configurable for different execution modes. In one mode the multiple register segments form a single register file where each register segment stores a Multiple Instructions Multiple Data (MIMD) super instruction matrix issuing four simultaneous instruction matrices where each individual instruction within each of the four simultaneous instruction matrices is a scalar or Single Instruction Multiple Data (SIMD). Another execution mode has the multiple register segments forming individual independent register tiles with individual register state to support simultaneous processing of separate threads, where each instruction matrix is associated with a separate thread and a separate register file segment.

Abstract: A technique for indicating a safe shared resource condition with respect to a disabled thread provides a mechanism for providing a fast indication to other hardware threads that a temporarily disabled thread can no longer impact shared resources, such as shared special-purpose registers and translation look-aside buffers within the processor core. Signals from pipelines within the core indicates whether any of the instructions pending in the pipeline impact the shared resources and if not, then the thread disable status is presented to the other threads via a state change in a thread status register. Upon receiving an indication that a particular hardware thread is to be disabled, control logic halts the dispatch of instructions for the particular hardware thread, and then waits until any indication that a shared resource is impacted by an instruction has cleared. Then the control logic updates the thread status to indicate the thread is disabled.

Abstract: Systems and methods for managing context switches among threads in a processing system. A processor may perform a context switch between threads using separate context registers. A context switch allows a processor to switch from processing a thread that is waiting for data to one that is ready for additional processing. The processor includes control registers with entries which may indicate that an associated context is waiting for data from an external source.

Abstract: A microprocessor capable of running both x86 instruction set architecture (ISA) machine language programs and Advanced RISC Machines (ARM) ISA machine language programs. The microprocessor includes a mode indicator that indicates whether the microprocessor is currently fetching instructions of an x86 ISA or ARM ISA machine language program. The microprocessor also includes a plurality of model-specific registers (MSRs) that control aspects of the operation of the microprocessor. When the mode indicator indicates the microprocessor is currently fetching x86 ISA machine language program instructions, each of the plurality of MSRs is accessible via an x86 ISA RDMSR/WRMSR instruction that specifies an address of the MSR. When the mode indicator indicates the microprocessor is currently fetching ARM ISA machine language program instructions, each of the plurality of MSRs is accessible via an ARM ISA MRRC/MCRR instruction that specifies the address of the MSR.

Abstract: A prefetch optimizer tool for an information handling system (IHS) may improve effective memory access time by controlling both hardware prefetch operations and software prefetch operations. The prefetch optimizer tool selectively disables prefetch instructions in an instruction sequence of interest within an application. The tool measures execution times of the instruction sequence of interest when different prefetch instructions are disabled. The tool may hold hardware prefetch depth constant while cycling through disabling different prefetch instructions and taking corresponding execution time measurements. Alternatively, for each disabled prefetch instruction in the instruction sequence of interest, the tool may cycle through different hardware prefetch depths and take corresponding execution time measurements at each hardware prefetch depth.

Abstract: A processing apparatus includes an execution unit which performs computation on two operand inputs each being selectable between read data from a register and an immediate value. The processing apparatus also includes another execution unit which performs computation on two operand inputs, one of which is selectable between read data from a register and an immediate value, and the other of which is an immediate value. A control unit determines, based on a received instruction specifying a computation on two operands, whether each of the two operands specifies read data from a register or an immediate value. Depending on the determination result, the control unit causes one of the execution units to execute the computation specified by the received instruction.