Abstract: An instruction set for a computer is described which includes instructions having a common predetermined bit length. That predetermined bit length can define a single operation or two independent operations. The instruction includes designated bits at predetermined bit locations which identify whether the instruction is a long instruction or a dual operation instruction.

Abstract: A mechanism for, and method of, processing multiply-accumulate instructions with out-of-order completion in a pipeline, for use in a processor having an at least four-wide instruction issue architecture, and a digital signal processor (DSP) incorporating the mechanism or the method. In one embodiment, the mechanism including: (1) a multiply-accumulate unit (MAC) having an initial multiply stage and a subsequent accumulate stage and (2) out-of-order completion logic, associated with the MAC, that causes interim results produced by the multiply stage to be stored when the accumulate stage is unavailable and allows younger instructions to complete before the multiply-accumulate instructions.

Abstract: The present invention relates generally to interfacing a processor with at least one coprocessor. One embodiment relates to a processor having a set of broadcast specifiers which it uses to selectively broadcast an operand that is being written to a register within the processor to a coprocessor communication bus. Each broadcast specifier may therefore include a broadcast indicator corresponding to each general purpose register of the processor. An alternate embodiment may also use the concept of broadcast regions where each broadcast region may have a corresponding broadcast specifier where one broadcast specifier may correspond to multiple broadcast regions. Alternatively, in one embodiment, the processor may use broadcast regions independent of the broadcast specifiers where the coprocessor is able to alter its functionality in response to the current broadcast region.

Abstract: A processing unit of the invention has multiple instruction pipelines for processing multi-threaded instructions. Each thread may have an urgency associated with its program instructions. The processing unit has a thread switch controller to monitor processing of instructions through the various pipelines. The thread controller also controls switch events to move from one thread to another within the pipelines. The controller may modify the urgency of any thread such as by issuing an additional instruction. The thread controller preferably utilizes certain heuristics in making switch event decisions. A time slice expiration unit may also monitor expiration of threads for a given time slice.

Abstract: A processing system provides predicate data that indicates whether instructions processed by a processor pipeline should be executed by the pipeline. In architecture, the system of the present invention utilizes a register, a pipeline, and predicate circuitry. The pipeline includes a first stage and a second stage for processing instructions of a computer program. The predicate circuitry is configured to read a first predicate value from the register and to receive a second predicate value. The predicate circuitry may transmit the first predicate value read from the register to the first stage and then select between the first predicate value and the second predicate value. The predicate value selected by the predicate circuitry is transmitted to the second stage.

Abstract: A processing arrangement for a computer comprising: first processor means (1) for processing a first set of instructions; and second processor means (2) for processing a second set of instructions, the second set of instructions being a subset of the first set of instructions, wherein the second processor means (2) is arranged to receive control signals and to process instructions in dependence upon those control signals without reference to the first processor means.

Abstract: A method and system for conditionally carrying out an operation defined in a computer instruction wherein a computer instruction is implemented on so-called packed operands; that is, operands containing a plurality of packed objects in respective lanes. An operation defined in the computer instruction is conditionally carried out in dependence on stored condition values which determine for each lane whether or not the operation is to be executed on objects in that lane.

Abstract: In a processing core, a newly received load instruction may be dependent upon a previously received store instruction. The core may include a predictor to predict such dependencies and provide an identification of a colliding store instruction. The load instruction may be stored in a scheduler with a dependency marker. Thereafter, the load instruction may be prevented from executing until after execution of the colliding store. Upon execution of the load, the accuracy of the prediction is confirmed. Upon retirement of the load instruction, new prediction results may be provided to the predictor.

Abstract: A digital signal processor may include a plurality of processing elements that are coupled together to accomplish a specialized function. Each processing element may utilize the same shared storage in a form of a plurality of general purpose registers. Each of these registers may be accessed by any of the processing elements. Each register may include a data storage section and a plurality of storage areas for data valid bits that indicate whether the data is valid or not for each of the plurality of processing elements.

Abstract: A REPEAT instruction for repeated execution of an associated instruction (INSTR). Once a program counter stores the address for the instruction to be repeated, it remains unchanged until the associated instruction (INSTR) has been executed the number of times indicated by a COUNT value in a preloaded register, or alternatively, by the REPEAT instruction itself. In this manner, the present invention reduces the number of instruction fetches required to repeatedly execute the associated instruction (INSTR). Consequently, there is a significant improvement in the efficiency of the program code execution.

Abstract: A method of run-time reconfiguration of a programmable unit is provided, the programmable unit including a plurality of reconfigurable function cells in a multidimensional arrangement. An event is detected. The source of the detected event is determined, and an address of an entry in a jump table is calculated as a function of the source of the event, the entry storing a memory address of a configuration for a reconfigurable function cell. The entry is retrieved and a state of a corresponding reconfigurable cell is determined. If the reconfigurable cell is in a reconfiguration state, the reconfigurable cell is reconfigured as a function of the configuration data. If the reconfigurable cell in not in reconfiguration state, the configuration data is stored in a FIFO.

Abstract: A branch prediction apparatus having a primary predictor and a secondary predictor that selectively overrides the primary predictor based on the type of branch instruction decoded. A branch target address cache in the primary branch predictor speculatively predicts a branch target address and direction based on an instruction cache fetch address prior to decoding the instruction, and the processor branches to the speculative target address if the speculative direction is predicted taken. Later in the pipeline, decode logic decodes the instruction and determines the branch instruction type, such as whether the branch instruction is a conditional branch, a return instruction, a program counter-relative type branch, an indirect branch, etc. Depending upon the branch type, if the primary and secondary predictions do not match, the processor branches based on the secondary prediction to override the branch taken based on the primary prediction.

Abstract: A re-configurable, streaming vector processor (100) is provided which includes a number of function units (102), each having one or more inputs for receiving data values and an output for providing a data value, a re-configurable interconnection switch (104) and a micro-sequencer (118). The re-configurable interconnection switch (104) includes one or more links, each link operable to couple an output of a function unit (102) to an input of a function unit (102) as directed by the micro-sequencer (118). The vector processor may also include one or more input-stream units (122) for retrieving data from memory. Each input-stream unit is directed by a host processor and has a defined interface (116) to the host processor. The vector processor also includes one or more output-stream units (124) for writing data to memory or to the host processor. The defined interface of the input-stream and output-stream units forms a first part of the programming model.

Abstract: A microprocessor caches in a branch target address cache (BTAC), for each of a plurality of previously executed branch instructions: a prediction of whether the branch instruction will be taken and is present in a cache line of instruction bytes provided by an instruction cache in response to a fetch address, a target address of the branch instruction, and a location of an opcode byte of the branch instruction within the cache line. The instruction cache provides the cache line to an instruction buffer and the BTAC provides the prediction, the target address, and the location in response to the fetch address. The microprocessor branches to the target address. A byte in the cache line within the instruction buffer indicated by the location provided by the BTAC is marked. An instruction decoder formats the instruction bytes in the cache line.

Abstract: An multi-threading processor is provided. The multi-threading processor includes a first instruction fetch unit and a second instruction fetch unit. A multi-thread scheduler unit is coupled to the first instruction fetch unit and the second instruction fetch unit. An execution unit, which executes a first active thread and a second active thread is coupled to the scheduler unit. The multi-threading processor also includes a register file coupled to the execution unit. The register file switches one of the first active thread and the second active threads with a first inactive thread.

Abstract: A system and method for enabling multithreading in a embedded processor, invoking zero-time context switching in a multithreading environment, scheduling multiple threads to permit numerous hard-real time and non-real time priority levels, fetching data and instructions from multiple memory blocks in a multithreading environment, and enabling a particular thread to modify the multiple states of the multiple threads in the processor core.

Abstract: System and method to reduce execution of instructions involving unreliable data in a speculative processor. A method comprises identifying scratch values generated during speculative execution of a processor, and setting at least one tag associated with at least one data area of the processor to indicate that the data area holds a scratch value. Such data areas include registers, predicates, flags, and the like. Instructions may also be similarly tagged. The method may be executed by an execution engine in a computer processor.

Abstract: A computation core includes a computation block, an addressing block and an instruction sequencer, which are coupled to a memory through a memory interface. The computation block includes a register file and dual execution units. The execution units include features for enhanced performance in executing digital signal computations. The computation core is configured for executing digital signal processor instructions and microcontroller instructions, while achieving efficient digital signal processor computation and high code density. A finite impulse response filter algorithm achieves high performance on the dual execution units.

Abstract: A mechanism for resource allocation in a processor, a method of allocating resources in a processor and a digital signal processor incorporating the mechanism or the method. In one embodiment, the mechanism includes: (1) categorization logic, associated with an earlier pipeline stage, that generates instruction type information for instructions to be executed in the processor and (2) priority logic, associated with a later pipeline stage, that allocates functional units of the processor to execution of the instructions based on the instruction type information.

Abstract: Methods and apparatus for creating microcode-implemented peripheral devices for a microcontroller core formed in a monolithic integrated circuit. The microcontroller core has a control store for storing microcode instructions; execution circuitry operable to execute microcode instructions from the control store; and means for loading a suite of one or more microcode-device modules defining an optional peripheral device, the optional peripheral device being implemented by microcode instructions executed by the execution circuitry in accordance with the definition provided by the microcode-device modules.