Abstract: An integrated circuit comprising: a processor; a plurality of external pins operatively coupled to the processor; and a permanently written memory operatively coupled to the processor, the memory having a plurality of regions each storing one or more respective boot properties for booting the processor. The processor is programmed to select one of the regions in dependence on an indication received via one or more of the external pins, to retrieve the one or more respective boot properties from the selected region, and to boot using the one or more retrieved boot properties.

Abstract: According to embodiments of the invention, there is disclosed a data processing unit, a method of operating the same, computer program product and an instruction. In one embodiment according to the invention, there is provided a data processing unit for a computer processor, the data processing unit comprising a deep register access mechanism capable of performing a permutation operation on at least one data operand accessed from a register file of the computer processor, the permutation operation being performed in series with (i) register access for the data operand and (ii) execution of a data processing operation on the operand.

Abstract: A logic circuit latch including an input stage for receiving a logical input signal and a pair of differential amplifiers, each having an input operatively coupled to the input stage, and at least one of them having an output arranged to supply the logical output of the latch. Each of the differential amplifiers includes a transistor connected as a load, and an output of each of the differential amplifiers is coupled to bias the load transistor of the other differential amplifier. If the latch switches from the transparent state to the closed state while the logical input signal is transitioning between logical levels, the differential amplifiers drive up the logical output of the latch if the logical input signal transitions from a first to a second logical level, and drive down the logical output of the latch if the input signal transitions from the second to the first logical level.

Abstract: A logic circuit latch including an input stage for receiving a logical input signal and a pair of differential amplifiers, each having an input operatively coupled to the input stage, and at least one of them having an output arranged to supply the logical output of the latch. Each of the differential amplifiers includes a transistor connected as a load, and an output of each of the differential amplifiers is coupled to bias the load transistor of the other differential amplifier. If the latch switches from the transparent state to the closed state while the logical input signal is transitioning between logical levels, the differential amplifiers drive up the logical output of the latch if the logical input signal transitions from a first to a second logical level, and drive down the logical output of the latch if the input signal transitions from the second to the first logical level.

Abstract: A double data rate memory interface circuit for transferring data between an interfacing device and double data rate memory device. The interface circuit comprises a data input for receiving a data signal from a first of those devices, and a strobe input for receiving a strobe signal from that first device. The interface circuit also comprises delay circuitry for supplying the data and strobe signals to the other device with a timing offset introduced therebetween. The delay circuitry comprises a software programmable storage medium and a digitally controllable delay element coupled to the storage medium, the delay element being arranged to control the timing offset in dependence on a delay setting programmed into that storage medium.

Abstract: A double data rate memory interface circuit for transferring data between an interfacing device and double data rate memory device. The interface circuit comprises a data input for receiving a data signal from a first of those devices, and a strobe input for receiving a strobe signal from that first device. The interface circuit also comprises delay circuitry for supplying the data and strobe signals to the other device with a timing offset introduced therebetween. The delay circuitry comprises a software programmable storage medium and a digitally controllable delay element coupled to the storage medium, the delay element being arranged to control the timing offset in dependence on a delay setting programmed into that storage medium.

Abstract: An integrated circuit comprising: a processor; a plurality of external pins operatively coupled to the processor; and a permanently written memory operatively coupled to the processor, the memory having a plurality of regions each storing one or more respective boot properties for booting the processor. The processor is programmed to select one of the regions in dependence on an indication received via one or more of the external pins, to retrieve the one or more respective boot properties from the selected region, and to boot using the one or more retrieved boot properties.

Abstract: The invention provides a receiver comprising a data input and a strobe input. The strobe signal transitions whenever two consecutive bits in the data signal are the same. The receiver comprises combining means for generating a recovered clock signal from a combination of the data and strobe signals. The receiver also comprises a first sampling stage arranged to sample the data signal in dependence on the recovered clock signal, the first sampling stage comprising a plurality of sampling circuits and being arranged to obtain consecutive samples of the data signal using alternating ones of the sampling circuits. A second sampling stage is arranged to sample the data from the first sampling stage in dependence on a local system clock signal.

Abstract: Embodiments of the present invention are related in general to data flow control in a network and in particular to synchronous packet flow control in a ring interconnect. An embodiment of a method may include rejecting an arriving packet at a destination node on a semiconductor chip's ring interconnect, e.g., an unbuffered, synchronous ring interconnect, if all of the destination node's buffers are not available, leaving the rejected packet on the ring interconnect to continue traversing the ring, and accepting the rejected packet upon arrival at the destination node, if a buffer is available. In an alternate embodiment, a method may include tracking the rejected packet as the rejected packet traverses the ring interconnect. An embodiment of an apparatus may include a semiconductor chip having a bidirectional ring interconnect and multiple nodes coupled to the bidirectional ring interconnect.

Abstract: A computer system comprises a processor that comprises a hardware branch predictor and software instructions executed by the processor. The software instructions comprise conditional branch instructions and separate static branch prediction instructions. The static branch prediction instructions comprise a plurality of groups of static branch prediction bits, each group being configurable to provide prediction information for a separate conditional branch instruction.

Abstract: A computer system has a processor that has a prediction array that avoids conflicts when the prediction array is accessed twice in once clock cycle to retrieve predictions for two separate conditional branch instructions. The prediction array is included as part of a branch prediction logic circuit that includes a bank control logic coupled to the prediction array. The bank control logic assures the conflict noted above is avoided. The prediction array preferably comprises multiple (e.g., 4) single-ported bank memory elements, each bank comprising multiple predictions. The bank control logic uses information associated with a previously fetched and branch predicted conditional branch instruction to generate a bank number for a current branch instruction. The generated bank number corresponds to one of the banks in the prediction array. The processor preferably fetches two (or more) groups (also called “slots”) of instructions each cycle.

Abstract: Embodiments of the present invention are related in general to on-chip integration of multiple components on a single die and in particular to on-chip integration of multiple processors via a bidirectional ring interconnect. An embodiment of a semiconductor chip includes a plurality of processors, an address space shared between the processors, and a bidirectional ring interconnect to couple the processors and the address space. An embodiment of a method includes calculating distances between a packet source and destination on multiple ring interconnects, determining on which interconnect to transport the packet, and then transporting the packet on the determined interconnect. Embodiments provide improved latency and bandwidth in a multiprocessor chip. Exemplary applications include chip multiprocessing.

Abstract: Embodiments of the present invention are related in general to data flow control in a network and in particular to synchronous packet flow control in a ring interconnect. An embodiment of a method may include rejecting an arriving packet at a destination node on a semiconductor chip's ring interconnect, e.g., an unbuffered, synchronous ring interconnect, if all of the destination node's buffers are not available, leaving the rejected packet on the ring interconnect to continue traversing the ring, and accepting the rejected packet upon arrival at the destination node, if a buffer is available. In an alternate embodiment, a method may include tracking the rejected packet as the rejected packet traverses the ring interconnect. An embodiment of an apparatus may include a semiconductor chip having a bidirectional ring interconnect and multiple nodes coupled to the bidirectional ring interconnect.

Abstract: A multi-ported SRAM memory cell includes a pair of inverters that holds the data bit. The state terminals of the memory cell connect via a separate read and write data path to the bit lines. The read bit lines connect to a pull-down transistor stack. The first transistor in the stack is gated by the word line, and the second transistor is gated by the state terminal of the memory cell. If the word line is asserted and the second transistor is turned on by the state of the memory cell, the bit line is connected to ground, thus pulling the bit line low. Conversely, if the second transmitter is not turned on, the bit line stays at a high voltage level. In a preferred embodiment, the memory cell is isolated from the pull-down transistor stack by an isolation buffer, such as an inverter, which inverts the voltage on the state terminal of the memory cell.

Abstract: A computer system has a processor that has a prediction array that avoids conflicts when the prediction array is accessed twice in once clock cycle to retrieve predictions for two separate conditional branch instructions. The prediction array is included as part of a branch prediction logic circuit that includes a bank control logic coupled to the prediction array. The bank control logic assures the conflict noted above is avoided. The prediction array preferably comprises multiple (e.g., 4) single-ported bank memory elements, each bank comprising multiple predictions. The bank control logic uses information associated with a previously fetched and branch predicted conditional branch instruction to generate a bank number for a current branch instruction. The generated bank number corresponds to one of the banks in the prediction array. The processor preferably fetches two (or more) groups (also called “slots”) of instructions each cycle.

Abstract: A pulse generator for use in generating pulses at different locations within a circuit has a first circuit 501 for a time dependent operation after receipt of a first input pulse and a second circuit 502 for carrying out a time dependent operation after receipt of a second input pulse after the first input pulse. A third circuit 503 is responsive to each of the first and second circuits 501,502 reaching respective predetermined conditions so that an output pulse is produced by the third circuit 503 at a time dependent on the average durations of operation of the first and second circuits 501 and 502.

Abstract: A scan cell is described which can function as either a positive edge triggered latch or a double edge triggered latch during normal functional operation of circuitry to be scan tested. It functions only as a positive edge triggered latch when scan testing of a logic structure is to be performed.