Abstract: An apparatus and method for branch prediction are disclosed. The branch predictor has four portions. The first includes a bimodal branch predictor in series with a local branch predictor; the second includes a global branch predictor. The first and second portions are in parallel and operate concurrently, and each provide an output received by the fourth portion. The third portion receives address data and selection data, and also provides output to the fourth portion. The fourth portion receives these outputs, and provides a branch prediction. The branch prediction is a selection of either the output from the first portion or the output from the second portion, based upon selection criteria received from the third portion.

Abstract: A branch prediction architecture is disclosed, having a branch predictor, a target address register, first and second multiplexors, a cache memory, and a trace cache. The branch predictor may advantageously be a series-parallel branch predictor, and alternatively may be a serial-BLG branch predictor or a choosing branch predictor. The first multiplexor receives an input from the target address register, and provides an output to the cache memory. The cache memory receives output from both the branch predictor and the first multiplexor, and provides an output to the second multiplexor. The trace cache receives the output from the branch predictor, and provides an output received by the second multiplexor. The second multiplexor, receiving input from both the trace cache and the cache memory, outputs branch predictions and instruction bundles.

Abstract: A method and apparatus for power management in a computer system is provided. A first power management signal is asserted, to indicate entry into a power management mode. An internal power management signal is generated, the internal power management signal being distinct from the first power management signal. The internal power management signal signals that a primary power connection is not stable. The primary power connection to the computer system is disconnected. The computer system is in said power management mode when the primary power connection is disconnected and the internal power management signal is asserted.

Abstract: The present invention is a method and apparatus for reducing power consumption of a computer system in a suspend mode. When the computer system enters a suspend mode, the main clock is turned off and the internal oscillator is used to refresh the memory. This internal oscillator is designed such that it is only operating when the computer system is in a suspend mode. The internal oscillator is further designed such that during suspend mode, it operates only to properly refresh the memory and enter or exit the suspend mode.

Abstract: A system for controlling the temperature inside a computer system housing involves determining whether a predetermined temperature set point has been exceeded. If the temperature set point has been exceeded, corrective action is attempted without adversely affecting the performance of the computer system. This may be accomplished by determining whether there are unused devices which are consuming power. If so, these devices may be transitioned to a lower power consumption state which may correspond to a lower heat generation state as well.

Abstract: A method and apparatus for a memory control system is provided. The memory control system includes a first memory controller designed to access and refresh a DRAM, using a clock, during a first operation mode. The memory control system further includes a second memory controller designed to maintain the DRAM during a second operation mode and to exit from the second operation mode. During the second operation mode a clock or the clock and power is turned off to the first memory controller, and upon returning to the first operation mode, no initialization of the first memory controller is needed. Since a significant proportion of the power is consumed by the first memory controller, power savings results from employing this technique.

Abstract: A portable computer includes a display screen which is detachably connected to the remainder of the computer. When the screen is detached, communication may continue between the screen and the housing using one of a plurality of techniques, including infrared communications, radio frequency communications, or an extensible cable link. In this way, a display screen may be positioned at a more convenient location, for example for viewing by a plurality of viewers.