Adaptive control of operating and body bias voltages

1. A method of operating a microprocessor comprising:

determining, independent of operating voltage, a desirable operating frequency for said microprocessor;

accessing information stored within and specific to said microprocessor, wherein said information comprises a set of body biasing voltages;

utilizing said information, computing an operating voltage for operating said microprocessor at said desirable operating frequency; and

operating said microprocessor at said operating voltage and said set of body biasing voltages.

2. The method of claim 1 wherein said information is encoded within said microprocessor prior to packaging of said microprocessor.

3. The method as described in claim 1 further comprising operating said microprocessor at said desirable operating frequency while operating at said operating voltage and said set of body biasing voltages.

4. The method as described in claim 1 wherein said information comprises at least two frequency-voltage characteristics corresponding to at least two different sets of body biasing voltages for said microprocessor.

5. The method as described in claim 4 wherein said information comprises coefficients of a quadratic approximation of a frequency-voltage characteristic of said microprocessor.

6. The method as described in claim 5 wherein said computing comprises evaluating said quadratic approximation of a frequency-voltage characteristic of said microprocessor.

7. The method as described in claim 1 wherein said information comprises a frequency adjustment term to adjust said desirable operating frequency for use in said computing.

8. The method as described in claim 7 wherein said computing comprises adjusting said desirable operating frequency by said frequency adjustment term.

9. The method as described in claim 1 wherein said information comprises a voltage adjustment term to adjust said operating voltage.

10. The method as described in claim 9 wherein said computing comprises utilizing said voltage adjustment term.

11. The method as described in claim 1 wherein said information comprises a point on a frequency-voltage characteristic of said microprocessor.

12. The method as described in claim 11 wherein said computing comprises utilizing said point.

13. A computer comprising:

a microprocessor integrated circuit;

an operating voltage supply for furnishing a selectable operating voltage to said microprocessor;

a plurality of voltage supplies coupled to said microprocessor for furnishing a set of selectable body biasing voltages;

a memory space coupled to said microprocessor comprising instructions to implement a method of operating said microprocessor, said method comprising:

determining a desirable operating frequency, independent of voltage, for said microprocessor;

accessing information stored within and specific to said microprocessor, wherein said information comprises a set of body biasing voltages;

utilizing said information, computing an operating voltage for operating said microprocessor at said desirable operating frequency;

commanding said operating voltage supply to furnish said operating voltage to said microprocessor; and

commanding said plurality of voltage supplies to furnish said set of body biasing voltages to said microprocessor.

14. The computer as described in claim 13 wherein said method further comprises operating said microprocessor at said operating voltage and said set of body biasing voltages.

15. The computer as described in claim 14 wherein said information comprises coefficients of a quadratic approximation of a frequency-voltage characteristic of said microprocessor integrated circuit at a set of body biasing voltages.

16. An electronic device comprising:

a microprocessor comprising information stored thereon of a quadratic approximation of a voltage-frequency relationship of said microprocessor at a set of body biasing voltages, wherein said information is specific to said microprocessor and used to select an operating voltage to be applied to said microprocessor based on a desired frequency of operation of said microprocessor.

17. An electronic device as described in claim 16 further comprising logic coupled to said microprocessor and for applying said efficient voltage and for causing said microprocessor to operate at said desired frequency of operation.

18. An electronic device as described in claim 16 wherein said information is stored in a plurality of programmable fuses integrated on said microprocessor.

19. An electronic device as described in claim 16 wherein said information is stored in a programmable memory integrated on said microprocessor.

20. An electronic device as described in claim 16 wherein said information is obtained after characterization of said microprocessor.

21. An electronic device as described in claim 16 wherein said information is programmed into said microprocessor at wafer level.

22. A method of operating a microprocessor comprising:

determining, independent of operating voltage, a desirable operating frequency for said microprocessor;

accessing information of a first frequency-voltage characteristic at a first set of body biasing voltages of said microprocessor; and

determining if operation of said microprocessor at said desirable operating frequency is possible at said first set of body biasing conditions of said microprocessor.

23. The method of claim 22 further comprising operating said microprocessor at said desirable operating frequency at said first set of body biasing conditions if said operation is possible at said first set of body biasing conditions.

24. The method of claim 23 further comprising operating said microprocessor at said desirable operating frequency at a second set of body biasing conditions if said operation is not possible at said first set of body biasing conditions.