Abstract: A cache may be programmed to disable one or more entries from allocation for storing memory data (e.g. in response to a memory transaction which misses the cache). Furthermore, the cache may be programmed to select which entries of the cache are disabled from allocation. Since the disabled entries are not allocated to store memory data, the data stored in the entries at the time the cache is programmed to disable the entries may remain in the cache. In one specific implementation, the cache also provides for direct access to entries in response to direct access transactions.

Abstract: A VCO for a PLL may include a ring oscillator having a power supply controlled in response to the VCO's control voltage input and an inverter having an input coupled to the ring oscillator's output and also supplied with a power supply controlled by the control voltage input. Together, the output of the ring oscillator and the output of the inverter may closely approximate a differential signal. The VCO may include an amplifier for amplifying a differential input to an output in the voltage domain of the system including the PLL. The output of the ring oscillator may be used as an input to the amplifier, and the output of the inverter may be used as the other input. The power supply terminals of the ring oscillator and the inverter may be coupled to outputs of a current mirror. In one implementation, the current mirror may not be cascoded.

Abstract: A method (and a computer accessible medium comprising one or more instructions which, when executed, implement the method) is contemplated. At least a first timing path is identified in a first timing report corresponding to a first partition of a circuit. For at least one timing constraint applied to the first timing path, a second timing path in a second partition of the circuit that causes the timing constraint is determined. A second timing report comprising the first timing path from the first timing report and the second timing path from the second partition is generated.

Abstract: A first dynamic logic circuit has an output node on which a scan value is provided during scan. One of one or more second dynamic logic circuits has an input coupled to the output node of the first dynamic logic circuit, and an output of the second dynamic logic circuits is sampled in response to the scan value during scan. In one embodiment, clock generation circuitry may be included which generates a first clock, a second clock, and a third clock. At least one evaluate pulse on the first clock prior is generated prior to sampling the output of the second dynamic logic circuits, the first clock controlling at least the evaluation of the second dynamic logic circuits. The second and third clocks are generated to isolate the output node from inputs to the first dynamic logic circuit responsive to the scan mode signal indicating that scan is active.

Abstract: A system includes a bus and a circuit for precharging the bus. The circuit may be coupled to receive a clock signal associated with the bus, and may be configured to precharge a bus during an interval of the period of the clock signal, the interval being between a first edge (rising or falling) and the subsequent edge (falling or rising). A second interval within the period and excluding the interval may be used to perform a bus transfer. In this manner, both precharging and transfer may be performed in the same clock cycle. Bandwidth of the bus may be improved since transfers may occur each clock cycle, rather than having a non-transfer clock cycle for precharging.

Abstract: A processor supports at least two different state save formats. Each format stores state in the form that the state exists in one or more operating modes of the processor. The operand size of the state save and state restore instructions may be used to indicate which state format is assumed by the processor during execution of the state save and state restore instructions. In one implementation, the processor implements a processor architecture compatible with the x86 architecture with enhancements to support 64 bit addressing and processing. In modes in which 64 bit addressing is supported, segmentation is not used. In 32 bit and 16 bit modes, segmentation is used. Thus, the address of a floating point instruction and/or operand may be indicated by a segment selector or pointer or by a pointer only.

Abstract: A processor, apparatus and method for storing segment descriptors of different sizes in a segment descriptor table are disclosed. Smaller segment descriptors may be segment descriptors similar to the x86 architecture definition, and larger segment descriptors may be used to provide virtual addresses (e.g. base addresses or offsets) having more the 32 bits. By providing a segment descriptor table that stores different sized segment descriptors, maintaining multiple segment descriptor tables for different operating modes may be avoidable while providing support for segment descriptors having addresses greater than 32 bits. In one embodiment, the larger segment descriptors may be twice the size of the smaller segment descriptors. The segment descriptor table may comprise entries, each capable of storing the smaller segment descriptor, and a larger segment descriptor may occupy two entries of the table.

Abstract: A processor supports several operating modes. In at least one of the operating modes, a segmented address space is used. In at least one other operating mode, an unsegmented address space is used. In the unsegmented address space, a canonical check applies to addresses. In the segmented address space, a segment limit check applies. In some cases, both a segment limit check and a canonical check applies dependent on the segment used (e.g. either user or table segments). An exception circuit selects one or more of the canonical check result(s) and the segment limit check result to generate an exception indication. The selection is dependent on the operating mode and the segment of the data reference. The processor may also perform selective truncation of addresses based on the operating mode and the segment.

Abstract: A processor supports a mode in which the default operand size is 32 bits, but which supports operand size overrides to 64 bits. Furthermore, the default operand size may automatically be overridden to 64 bits for instructions having an implicit stack pointer reference and for near branch instructions. The overriding of the default operand size may occur without requiring an operand size override encoding in these instructions. In one embodiment, the instruction set specifying the instructions may be a variable byte length instruction set (e.g. x86), and the operand size override encoding may be a prefix byte which increases the instruction length.

Abstract: A method is contemplated. According to the method, capacitances in a first resistance/capacitance (RC) extraction corresponding to a circuit are modified. Each capacitance is modified to estimate Miller effect on that capacitance. A ratio of a total capacitance on a first wire after the modification in the first RC extraction to a total capacitance on the first wire before the modification in the first RC extraction is calculated. Capacitances in a second RC extraction that are coupled to the first wire are modified according to the ratio. The second RC extraction is a reduced extraction as compared to the first RC extraction. A timing analysis is performed for the circuit using the second RC extraction with capacitances modified to estimate Miller effect.

Abstract: A system and method for performing a sync operation for multiple devices in a computer system is provided. The computer system may include a plurality of devices and a plurality of agents. The agents may be configured to perform tasks on behalf of the devices. A busy bit and a counter may be included for each of the agents. One of the devices may become an observer by initiating a sync operation. In response to a sync operation, busy agents may be identified using the busy bit for each agent. The busy agents may then be monitored to determine when each one has cycled using the busy bit and the counter for each busy agent. A busy agent may be determined to have cycled in response to its busy bit indicating that it is no longer busy or in response to its counter value differing from the counter value at the time the sync operation was initiated. Once each of the busy agents have cycled, the observer may determine that the sync operation is complete.

Abstract: A CAM may include a plurality of CAM cells. Each CAM cell is configured to generate an output indicating if a corresponding input bit and the bit stored in that CAM cell match. A circuit is configured to logically AND the outputs to generate a hit output. A first compare line generator circuit is configured to generate a first pulse responsive to a clock signal and a data signal and a second compare line generator circuit is configured to generate a second pulse responsive to the clock signal and the complement of the data signal. A CAM may include a circuit configured to generate a pulse indicating a hit in an entry of the CAM and a latch circuit configured to capture the pulse responsive to the first clock signal and configured to clear responsive to the second clock signal. A first CAM may store a value in each entry and may further store a compare result.

Abstract: A conditional clock buffer circuit includes a clock output and is coupled to receive a clock input and a condition signal. The conditional clock buffer circuit includes a first circuit coupled to receive the clock input and a second circuit coupled to receive the clock input and the condition signal. The first circuit is configured to generate a first state on the clock output responsive to a first phase of the clock input. The second circuit is configured to conditionally generate a second state on the clock output responsive to the condition signal during a first portion of a second phase of the clock input. In one implementation, one or more of the conditional clock buffer circuits may be included in a clock tree. The clock tree may also include one or more levels of buffering.

Abstract: A first tag is assigned to a branch instruction. Dependent on the type of branch instruction, a second tag is assigned to an instruction in the branch delay slot of the branch instruction. The second tag may equal the first tag if the branch delay slot is unconditional for that branch, and may equal a different tag if the branch delay slot is conditional for the branch. If the branch is mispredicted, the first tag is broadcast to pipeline stages that may have speculative instructions, and the first tag is compared to tags in the pipeline stages. If the tag in a pipeline stage matches the first tag, the instruction is not cancelled. If the tag mismatches, the instruction is cancelled.

Abstract: A method for locating a repair solution for a memory that includes a memory array containing a plurality of rows and a plurality of columns, N redundant rows, and M redundant columns. Both N and M are integers, where N is greater than or equal to zero and M is greater than or equal to zero. The N redundant rows and the M redundant columns are collectively referred to as redundant lines. The method includes generating a first defect matrix defects in the memory array. Additionally, the method includes recursively, until either the repair solution is found or the redundant lines are consumed: selecting a first line in the defect matrix and having at least one defect; generating a second defect matrix by eliminating at least the defects in the first line from the first defect matrix; and determining if the repair solution is found.

Abstract: A system on a chip for network devices. In one implementation, the system on a chip may include (integrated onto a single integrated circuit), a processor and one or more I/O devices for networking applications. For example, the I/O devices may include one or more network interface circuits for coupling to a network interface. In one embodiment, coherency may be enforced within the boundaries of the system on a chip but not enforced outside of the boundaries.

Abstract: A clock multiplier circuit is receives an input signal and generates a clock output signal. The clock multiplier circuit generates a number of pulses to be used as the clock output signal, wherein the pulses have a pulsewidth that is independent of the number of pulses generated and independent of the frequency of a clock control signal used for masking. The clock multiplier circuit includes an oscillator, a storage device for synchronization of the masking signal to the pulses and a logic circuit to generate the clock output signal. The clock multiplier circuit causes a number of unmasked pulses to be output as the output clock signal in response to the clock control signal, while other pulses are masked.

Abstract: A storage management system may provide virtual storage devices for use by an operating system. The storage management system may map files representing the virtual storage devices to a plurality of volumes to be stored on physical storage devices. In various embodiments, the storage management system may include storage management components which manage the files representing the virtual storage devices. In one implementation, the storage management system may support a set of storage commands for the virtual storage devices, including standard commands used by the operating system to communicate with storage devices, and additional commands for communicating with the storage management components.

Abstract: A PLL may include a voltage regulator for providing a regulated voltage to one or more PLL components (e.g. a charge pump, a voltage controlled oscillator, etc.). The PLL components may be noise sensitive components, and the regulated voltage may reduce noise received from the power supply. Additionally, a level shifter may be coupled between the PLL components and a phase/frequency detector. The level shifter may be supplied by the regulated voltage from the voltage detector. In another implementation, a PLL may include a programmable charge pump and a programmable loop filter. For example, the reference current to the charge pump may be changed, thus changing the rate at which the charge pump can change an output voltage (the control voltage to a voltage controlled oscillator in the PLL). The loop filter components may be changed to change the frequency ranges filtered by the loop filter.

Abstract: A cache is configured to receive direct access transactions. Each direct access transaction explicitly specifies a way of the cache. The cache may alter the state of its replacement policy in response to a direct access transaction explicitly specifying a particular way of the cache. The state may be altered such that a succeeding cache miss causes an eviction of the particular way. Thus, a direct access transaction may be used to provide a deterministic setting to the replacement policy, providing predictability to the entry selected to store a subsequent cache miss. In one embodiment, the replacement policy may be a pseudo-random replacement policy. In one embodiment, a direct access transaction also explicitly specifies a cache storage entry to be accessed in response to the transaction.