Abstract: An energy-saving circuit and method using charge equalization across complementary nodes reduces power consumption in memory circuits and other circuits such as wide multiplexers having complementary high-capacitance nodes. A change detection circuit detects a state change to be applied to the bitlines, and generates a pulse if a state change is to be applied. A pass gate connected between the nodes is activated in response to the pulse to equalize the charge on the bitlines. The driver circuit enable inputs are also delayed, so that the bitlines are not driven until after the charge has been equalized and the pass gate disabled. In one embodiment, the driver circuits are only enabled momentarily by a pulsed output of the change detector and keeper circuits are employed to retain the bitlines in their asserted states.

Abstract: A method for evaluating memory cell performance provides for circuit delay and performance measurements in an actual memory circuit environment. A ring oscillator implemented in a row of memory cells and having outputs connected to one or more bitlines along with other memory cells that are substantially identical to the ring oscillator cells is operated by the method. Logic may be included for providing a fully functional memory array, so that the cells other than the ring oscillator cells can be used for storage when the ring oscillator row wordlines are disabled. One or both power supply rails of individual cross-coupled inverter stages forming static memory cells used in the ring oscillator circuit may be isolated from each other in order to introduce a voltage asymmetry so that circuit asymmetry effects on delay can be evaluated.

Abstract: A method and apparatus for sending thread-execution-state-sensitive supervisory commands to a simultaneous multi-threaded processor provides a mechanism for sending supervisory commands that must be executed only for live threads. The commands may be sent from a service processor or another primary processor in the system or may be supplied by the processor itself through supervisory software control. Since the state of execution of one or more threads may change dynamically within a processor core, an external processor will not know the thread execution state at the time the command operates. The method and apparatus provide a command set and logic that supports selective execution of particular commands directed at “alive” threads (or threads in some other determinable execution state), whereby the command is performed only on resources and/or execution units depending on the actual state of thread execution when the command operates within the processor.

Abstract: A histogram difference method and system for power/performance measurement and management has low data storage requirements while supporting multiple monitoring applications having different update rates. Histogram data for power usage and/or performance mode is collected at a predetermined rate and the histogram data is read out at periodic intervals by the monitoring applications. The monitoring applications subtract the histogram data from previously read histogram data set to determine a interval difference histogram. The minimum and maximum values for the interval are the lowest-valued and highest-valued bin in the interval difference histogram that have a count greater than zero. The average value for the interval is the mean of the interval difference histogram. A conservative bound of the maximum and minimum values for a system can be determined by adding the values of the maximum and minimum values determined for each subsystem in the system.

Abstract: A method and system for backup and restore of a context encryption key (CEK) for a trusted device within a secured processing system maintains security of virtualized trusted device contexts, providing for replacement of a trusted device in the field. The CEK is encrypted along with a system identifier by a random number to yield a first result. The first result is again encrypted with a manufacturer public key. The resulting blob is stored along with the random number. To restore, the system sends the blob and the device ID to a server. The server obtains the first result by decrypting with the manufacturer private key, re-encrypts with the device public key and sends the new result back. The system sends the new result to the device along with the associated random number. The device decrypts the new result using its private key and decrypts the CEK using the random number.