Abstract: In one embodiment, an integrated circuit comprises at least one logic circuit supplied by a first supply voltage and at least one memory circuit coupled to the logic circuit and supplied by a second supply voltage. The memory circuit is configured to be read and written responsive to the logic circuit even if the first supply voltage is less than the second supply voltage during use. In another embodiment, a method comprises a logic circuit reading a memory cell, the logic circuit supplied by a first supply voltage; and the memory cell responding to the read using signals that are referenced to the first supply voltage, wherein the memory cell is supplied with a second supply voltage that is greater than the first supply voltage during use.

Abstract: In one embodiment, a processor comprises a data cache configured to store a plurality of cache blocks and a control unit coupled to the data cache. The control unit is configured to flush the plurality of cache blocks from the data cache responsive to an indication that the processor is to transition to a low power state in which one or more clocks for the processor are inhibited.

Abstract: In one embodiment, a system comprises at least a first node and a second node coupled to a network. The second node comprises a local memory and a direct memory access (DMA) controller coupled to the local memory. The first node is configured to transmit at least a first packet to the second node to access data in the local memory and at least one other packet that is not coded to access the local memory. The second node is configured to capture the packet from a data link layer of a protocol stack, and wherein the DMA controller is configured to perform one more transfers with the local memory to access the data specified by the first packet responsive to the first packet received from the data link layer. The second node is configured to process the other packet to a top of the protocol stack.

Abstract: In one embodiment, an apparatus comprises a logic circuit, a plurality of passgates, at least one pulse generator, and a plurality of latch elements. The logic circuit has a plurality of inputs, and each of the passgates has an output directly connected to one of the inputs. The pulse generator is configured to generate a pair of control signals to the passgates, and is configured to generate pulses on the pair of control signals to open the passgates. Each of the latch elements is connected to a respective input and is configured to latch the signal on the respective input when passgates are open and to retain the signal on the respective input when the passgates are closed.

Abstract: In one embodiment, a processor comprises a prefetch unit coupled to a data cache. The prefetch unit is configured to concurrently maintain a plurality of separate, active prefetch streams. Each prefetch stream is either software initiated via execution by the processor of a dedicated prefetch instruction or hardware initiated via detection of a data cache miss by one or more load/store memory operations. The prefetch unit is further configured to generate prefetch requests responsive to the plurality of prefetch streams to prefetch data in to the data cache.

Abstract: In one embodiment, an integrated circuit comprises resonance limiter circuits coupled to a power supply connection of the integrated circuit. The resonance limiter circuits are configured to detect oscillation on the power supply connection at a resonant frequency, and to dampen the resonant frequency oscillation responsive to detecting the oscillation. In some embodiments, the resonance limiter circuits may damp oscillation at or above the resonant frequency or approximately the resonant frequency (e.g. somewhat below the resonance frequency). The resonant frequency depends on a package of the integrated circuit. In an embodiment, a resonance limiter circuit comprises a filter and a transistor coupled in parallel with the filter between a power supply connection and a ground connection. The filter is tuned to approximately a resonant frequency (e.g. the lowest resonant frequency) that depends on a package corresponding to an integrated circuit into which the resonance limiter circuit is fabricated.

Abstract: In one embodiment, an integrated circuit comprises at least one measurement unit configured to generate an output indicative of a supply voltage at which the integrated circuit is operable for a given operating frequency and a control unit coupled to receive the output. The control unit is configured to generate a voltage control output indicative of a requested supply voltage for the integrated circuit responsive to the output. The voltage control output may be output from the integrated circuit for use by circuitry external to the integrated circuit in generating the supply voltage for the integrated circuit.

Abstract: In one embodiment, a memory circuit comprises one or more first memory cells, each of the one or more first memory cells configured to store at least one bit; one or more second memory cells, each of the one or more second memory cells configured to store at least one bit; and one or more read port circuits physically located between the first memory cells and the second memory cells. Each of the read port circuits is coupled to receive the at least one bit from each of the first memory cells and each of the second memory cells, and each of the read port circuits is configured to output the at least one bit from a selected memory cell of the first memory cells and the second memory cells responsive to a plurality of wordline signals coupled to the read port circuit.

Abstract: In various embodiments, an apparatus comprises a plurality of agents and an interconnect. In one embodiment, the plurality of agents includes first through fourth agents. The interconnect comprises a plurality of segments that are switchable (e.g. using a plurality of selection circuits) to form communication paths between the agents, and a first segment is included in a first communication path from the first agent to the second agent, and is also included in a second communication path from the third agent to the fourth agent. In another embodiment, each segment is driven by a selection circuit. At least one selection circuit has at least one segment and an output from at least one agent as inputs. In yet another embodiment, an arbiter is configured to determine a communication path on the interconnect for each requesting agent to the destination agent over the segments.

Abstract: In one embodiment, an apparatus comprises a voltage-controlled oscillator (VCO) that comprises a circuit coupled to receive an input control voltage to the VCO and configured to generate a second voltage responsive to the input control voltage, a summator coupled to receive the input control voltage and the second voltage, and an oscillator coupled to receive the output voltage of the summator. The summator is configured to combine the input control voltage and the second voltage to generate the output voltage. The oscillator is configured to oscillate an output signal, wherein a frequency of oscillation of the output signal is controlled by the output voltage of the summator.

Abstract: In one embodiment, a combined mux/storage circuit comprises a latch element, a plurality of passgates connected to the latch element, and logic circuitry. Each passgate has an input coupled to receive a signal representing a respective mux input and is configured to open and close responsive to respective pairs of control signals. The logic circuitry is coupled to receive a clock signal, a delayed clock signal, and mux select control signals, and is configured to generate pulses on the pair of control signals to control a passgate that has an input coupled to receive the signal representing a selected mux inputs, as indicated by the mux select control signals. The width of the pulses is dependent on the clock signal and the delayed clock signal. The latch element is configured to latch the signal representing the selected mux input in parallel with the selected mux input being driven as an output of the mux/storage circuit.

Abstract: In one embodiment, a jitter detector comprises a logic circuit coupled to receive a plurality of inputs indicative of states captured from a plurality of outputs of a delay chain responsive to a first clock input and a plurality of clocked storage devices coupled to the logic circuit. The logic circuit is configured to identify a first input of the plurality of inputs that is: (i) captured in error from a corresponding one of the plurality of outputs of the delay chain, and (ii) the corresponding one of the plurality of outputs of the delay chain is least delayed by the delay chain among the plurality of outputs that are captured in error. The plurality of clocked storage devices are configured to accumulate an indication of which of the plurality of outputs have been captured in error over a plurality of clock cycles of the first clock input.

Abstract: In one embodiment, an integrated circuit comprises a first circuit and a control unit coupled to the first circuit. The first circuit comprises at least one transistor and implements one or more operations for which the integrated circuit is designed. The control unit is configured to generate at least one substrate bias voltage for the first circuit.

Abstract: In one embodiment, a combined mux/storage circuit comprises a latch element, a plurality of passgates connected to the latch element, and logic circuitry. Each passgate has an input coupled to receive a signal representing a respective mux input and is configured to open and close responsive to respective pairs of control signals. The logic circuitry is coupled to receive a clock signal, a delayed clock signal, and mux select control signals, and is configured to generate pulses on the pair of control signals to control a passgate that has an input coupled to receive the signal representing a selected mux inputs, as indicated by the mux select control signals. The width of the pulses is dependent on the clock signal and the delayed clock signal. The latch element is configured to latch the signal representing the selected mux input in parallel with the selected mux input being driven as an output of the mux/storage circuit.

Abstract: In one embodiment, an apparatus comprises a logic circuit, a plurality of passgates, at least one pulse generator, and a plurality of latch elements. The logic circuit has a plurality of inputs, and each of the passgates has an output directly connected to one of the inputs. The pulse generator is configured to generate a pair of control signals to the passgates, and is configured to generate pulses on the pair of control signals to open the passgates. Each of the latch elements is connected to a respective input and is configured to latch the signal on the respective input when passgates are open and to retain the signal on the respective input when the passgates are closed.

Abstract: In one embodiment, a storage circuit comprises a first passgate having an input coupled to receive a signal representing a data input to the storage circuit and further having an output connected to a storage node in the storage circuit. The storage circuit also comprises a scan latch having an input connected to a scan data input to the storage circuit and further coupled to receive a scan enable input. The scan latch is configured to store the scan data input responsive to an assertion of the scan enable input, and also comprises a second passgate connected to the storage node and having an input coupled to receive the stored scan data. Each of the first passgate and the second passgate are coupled to receive respective pairs of control signals to control opening and closing of the passgates, wherein the scan enable signal controls which of the respective pairs of control signals are pulsed.

Abstract: An interface unit may comprise a buffer configured to store requests that are to be transmitted on an interconnect and a control unit coupled to the buffer. In one embodiment, the control unit is coupled to receive a retry response from the interconnect during a response phase of a first transaction for a first request stored in the buffer. The control unit is configured to record an identifier supplied on the interconnect with the retry response that identifies a second transaction that is in progress on the interconnect. The control unit is configured to inhibit reinitiation of the first transaction at least until detecting a second transmission of the identifier. In another embodiment, the control unit is configured to assert a retry response during a response phase of a first transaction responsive to a snoop hit of the first transaction on a first request stored in the buffer for which a second transaction is in progress on the interconnect.

Abstract: In one embodiment, a processor comprises a plurality of storage locations, a decode circuit, and a status/control register (SCR). Each storage location is addressable as a speculative register and is configured to store result data generated during execution of an instruction operation and a value representing an update for the SCR. The value includes at least a first encoding that represents an update to a plurality of bits in the SCR, and a first number of bits in the plurality of bits is greater than a second number of bits in the first encoding. The decode circuit is coupled to receive the first encoding from a first storage location responsive to retirement of a first instruction operation assigned to use the first storage location as a destination, and is configured to decode the first encoding and generate the plurality of bits. The decode circuit is configured to update the SCR.

Abstract: In one embodiment, an integrated circuit comprises at least one digital leakage detector that comprises digital circuitry configured to detect an approximation of a magnitude of the leakage current in transistors of the integrated circuit and configured to generate a digital output representing the approximated magnitude. In another embodiment, a leak detector comprises leak circuits and clocked storage devices. Each leak circuit is configured to generate an output signal indicative of a different magnitude of leakage current in a transistor. The clocked storage devices are configured to capture a state representing the output signals of the leak circuits. In another embodiment, a method comprises running a test for leakage current in a digital leakage detector, wherein a digital output of the digital leakage detector represents a magnitude of a leakage current being experienced by the integrated circuit during use; and outputting the digital output from the integrated circuit.

Abstract: In one embodiment, a processor comprises a core configured to execute a data cache block write instruction and an interface unit coupled to the core and to an interconnect on which the processor is configured to communicate. The core is configured to transmit a request to the interface unit in response to the data cache block write instruction. If the request is speculative, the interface unit is configured to issue a first transaction on the interconnect. On the other hand, if the request is non-speculative, the interface unit is configured to issue a second transaction on the interconnect. The second transaction is different from the first transaction. For example, the second transaction may be an invalidate transaction and the first transaction may be a probe transaction. In some embodiments, the processor may be in a system including the interconnect and one or more caching agents.