Abstract: A power management method for a pipelined computer system in accordance with one or both of a power management signal and a power management instruction.

Abstract: A pipelined computer system with power management control in accordance with one or both of a power management signal and a power management instruction.

Abstract: An instruction-initiated method for suspending operation of a pipelined data processor by selectively disabling a clock signal to pipeline subcircuitry in response to an instruction executed by the pipeline subcircuitry.

Abstract: An instruction-initiated power management method for a pipelined data processor by which a clock signal to pipeline subcircuitry is selectively disabled in response to an instruction executed by the pipeline subcircuitry.

Abstract: A signal-initiated method for suspending operation of a pipelined data processor by selectively disabling a clock signal to pipeline subcircuitry in response to at least one control signal.

Abstract: A signal-initiated power management method for a pipelined data processor by which a clock signal to pipeline subcircuitry is selectively disabled in response to at least one control signal.

Abstract: A pipelined data processor with instruction-initiated power management control in which a plurality of subcircuits, including pipeline subcircuitry and circuitry for generating and controlling at least one clock signal are responsive to an instruction executed by the pipeline subcircuitry by selectively disabling a clock signal to the pipeline subcircuitry.

Abstract: A pipelined data processor with signal-initiated power management control in which a plurality of subcircuits, including pipeline subcircuitry, and circuitry for generating and controlling at least one clock signal are responsive to at least one control signal by disabling a clock signal to the pipeline subcircuitry.

Abstract: A processing unit includes a plurality of subcircuits and circuitry for generating clock signals thereto. Detection circuitry detects the assertion of a control signal and disabling circuitry is operable to disable the clock signals to one or more of the subcircuits responsive to the control signal.

Abstract: A processing unit includes a plurality of subcircuits and circuitry for generating clock signals thereto. Detection circuitry detects the assertion of a control signal and disabling circuitry is operable to disable the clock signals to one or more of the subcircuits responsive to the control signal.

Abstract: A processing unit includes a plurality of subcircuits and circuitry for generating clock signals thereto. Detection circuitry detects the assertion of a control signal and disabling circuitry is operable to disable the clock signals to one or more of the subcircuits responsive to the control signal.

Abstract: A processing unit includes a plurality of subcircuits and circuitry for generating clock signals thereto. Detection circuitry detects the assertion of a control signal and disabling circuitry is operable to disable the clock signals to one or more of the subcircuits responsive to the control signal.

Abstract: In accordance with the presently claimed invention, power consumption reduction control is provided to a processor used to execute instructions for data processing. A power management control signal is provided to the processor in accordance with conditions associated with the processor being operated in normal and reduced power consumption modes of operation, and an acknowledgement signal indicative of such reduced power consumption mode of operation is returned in correspondence with the power management control signal.

Abstract: Power consumption reduction control circuitry external and coupled to a processor used to execute instructions for data processing. A power management control signal is provided to the processor in accordance with conditions associated with the processor being operated in normal and reduced power consumption modes of operation, and an acknowledgement signal indicative of such reduced power consumption mode of operation is returned in correspondence with the power management control signal.

Abstract: A processing unit includes a plurality of subcircuits and circuitry for generating clock signals thereto. Detection circuitry detects the assertion of a control signal and disabling circuitry is operable to disable the clock signals to one or more of the subcircuits responsive to the control signal.

Abstract: A technique for invoking a low power operational mode in response to a halt instruction is used in a computer system that includes a processor coupled to external logic. The processor includes at least (i) a pipeline subcircuit to execute programmed instructions, including halt instructions, (ii) an interrupt handling subcircuit to handle interrupts generated by external interrupt logic, and (iii) clock generator circuitry that supplies clock signals to the pipeline and interrupt handling subcircuits. In response to execution of a halt instruction, the processor (i) enters the low power operational mode in which power consumption is reduced at least for the pipeline subcircuit, but without stopping the supply of clock signals to the interrupt handling subcircuit, and (ii) generates an acknowledgement signal to the external logic indicating that the clock signals to the pipeline subcircuit are being stopped, thereby entering the low power operational mode.

Abstract: A technique for invoking a low power operational mode in response to a halt instruction is used in a computer system that includes a processor coupled to external logic. The processor includes at least (i) a pipeline subcircuit to execute programmed instructions, including halt instructions, (ii) an interrupt handling subcircuit to handle interrupts generated by external interrupt logic, and (iii) clock generator circuitry that supplies clock signals to the pipeline and interrupt handling subcircuits. In response to execution of a halt instruction, the processor (i) stops the clock generator circuitry from supplying clock signals to the pipeline subcircuit, but not to the interrupt handling subcircuit, and (ii) generates an acknowledgement signal to the external logic indicating that the clock signals to the pipeline subcircuit are being stopped, thereby entering the low power operational mode.

Abstract: A write-back coherency system is used, in an exemplary embodiment, to implement write-back caching in an x86 processor installed in a multi-master computer system that does not support a write-back protocol for maintaining coherency between an internal cache and main memory during DMA operations. The write-back coherency system interrupts the normal bus arbitration operation to allow export of dirty data. In response to an arbitration-request (such as HOLD), if the internal cache contains dirty data, the processor is inhibited from providing arbitration-acknowledge (such as HLDA) until the dirty data is exported (the cache is dynamically switched to write-through mode to prevent data in the cache from being made dirty while the bus is arbitrated away). While the requesting bus master is accessing memory, bus snooping is performed and invalidation logic invalidates at least those cache locations corresponding to locations in memory that are affected by the requesting bus master.

Abstract: A write-back coherency system, including FLUSH/INVAL and LOCK protocols, is used, in an exemplary embodiment, in a microprocessor used in a computer system that selectively provides to the processor FLUSH and INVAL signals to implement a limited write-back protocol. The FLUSH/INVAL protocol is used by the computer system to control export and invalidate operations. In response to a FLUSH signal, the microprocessor exports dirty data from the cache. If INVAL is also asserted, the cache is also invalidated (i.e., if FLUSH is asserted and INVAL is not asserted, no invalidation is performed). With the LOCK protocol, LOCKed reads are serviced out of the cache for read hits--however, to maintain compatibility with computer systems that expect a LOCK operation to involve a read followed by a write access to external memory, the microprocessor will still run the external LOCKed read cycle, ignoring the returned data.

Abstract: A processing unit includes a plurality of subcircuits and circuitry for generating clock signals thereto. Detecting circuitry detects the assertion of a first signal indicative of a request for suspending operation of the processing unit and the assertion of a second signal indicating the state of operation of a coprocessing unit. Disabling circuitry is operable to disable clock signals to one or more of the subcircuits responsive to the first and second control signals.