Conserving power by reducing voltage supplied to an instruction-processing portion of a processor

1. A method for reducing static power consumption of a processor, comprising:

receiving a signal indicating that instruction execution within the processor is to be temporarily halted; and

in response to the signal,

halting an instruction-processing portion of the processor, and

reducing a voltage supplied to the instruction-processing portion of the processor, while maintaining full voltage to a second portion of the processor, wherein reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to a minimum value that maintains state information within the instruction-processing portion of the processor;

whereby the second portion of the processor can continue to operate while the instruction-processing portion of the processor is in a reduced power mode.

2. The method of claim 1 , wherein reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to zero.

3. The method of claim 2 , further comprising saving state information from the instruction-processing portion of the processor prior to reducing the voltage supplied to the instruction-processing portion of the processor, wherein saving state information includes saving state information to one of, the second portion of the processor and a main memory.

4. The method of claim 3 , wherein upon receiving a wakeup signal the method further comprises:

restoring full voltage to the instruction-processing portion of the processor;

restoring state information to the instruction-processing portion of the processor; and

resuming processing of computer instructions.

5. The method of claim 1 , wherein maintaining full voltage to the second portion of the processor involves maintaining full voltage to a snoop-logic portion of the processor, whereby the processor can continue to perform cache snooping operations while the instruction-processing portion of the processor is in the reduced power mode.

6. The method of claim 1 , further comprising reducing the voltage to a cache memory portion of the processor upon receiving the signal.

7. The method of claim 6 , further comprising writing cache memory data to main memory prior to reducing the voltage.

8. The method of claim 1 , wherein the second portion of the processor includes a control portion of the processor that includes interrupt and clock circuitry.

9. The method of claim 1 , wherein the second portion of the processor includes a cache memory portion of the processor.

10. An apparatus, for reducing static power consumption of a processor, comprising:

a receiving mechanism that is configured to receive a signal indicating that instruction execution within the processor is to be temporarily halted;

a halting mechanism that is configured to halt an instruction-processing portion of the processor; and

a voltage reducing mechanism that is configured to reduce a voltage supplied to the instruction-processing portion of the processor, while maintaining full voltage to a second portion of the processor, wherein reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to a minimum value that maintains state information within the instruction-processing portion of the processor;

whereby the second portion of the processor can continue to operate while the instruction-processing portion of the processor is in a reduced power mode.

11. The apparatus of claim 10 , wherein reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to zero.

12. The apparatus of claim 11 , further comprising a saving mechanism that is configured to save state information from the instruction-processing portion of the processor prior to reducing the voltage supplied to the instruction-processing portion of the processor, wherein saving state information includes saving state information to one of, the second portion of the processor and a main memory.

13. The apparatus of claim 12 , further comprising:

a voltage restoring mechanism that is configured to restore full voltage to the instruction-processing portion of the processor;

a state restoring mechanism that is configured to restore state information to the instruction-processing portion of the processor; and

a resuming mechanism that is configured to resume processing of computer instructions.

14. The apparatus of claim 10 , wherein maintaining full voltage to the second portion of the processor involves maintaining full voltage to a snoop-logic portion of the processor, whereby the processor can continue to perform cache snooping operations while the instruction-processing portion of the processor is in the reduced power mode.

15. The apparatus of claim 10 , wherein the voltage reducing mechanism is further configured to reduce the voltage to a cache memory portion of the processor upon receiving the signal.

16. The apparatus of claim 15 , further comprising a writing mechanism that is configured to write cache memory data to main memory prior to reducing the voltage.

17. The apparatus of claim 10 , wherein the second portion of the processor includes a control portion of the processor that includes interrupt and clock circuitry.

18. The apparatus of claim 10 , wherein the second portion of the processor includes a cache memory portion of the processor.