Searching a content addressable memory with modifiable comparands

1. A non-transitory computer-readable storage medium having instructions stored thereon, the instructions comprising:

instructions for searching a content addressable memory based on a comparand, wherein the comparand is stored on a comparand data register, and wherein the comparand comprises a collection of bits;

instructions for receiving a comparand overlay pointer;

instructions for generating a modified comparand by modifying the comparand, wherein the modified comparand is based at least in part on a comparand overlay data value and the comparand overlay pointer; and

instructions for searching the content addressable memory with the modified comparand.

2. The non-transitory computer-readable storage medium of claim 1 , wherein instructions for generating the modified comparand comprise instructions for modifying selected bits of the comparand.

3. The non-transitory computer-readable storage medium of claim 2 , wherein the instructions are further configured to copy the comparand to a temporary comparand memory prior to modifying the selected bits of the comparand.

4. The non-transitory computer-readable storage medium of claim 2 , wherein the comparand overlay pointer identifies the selected bits of the comparand to modify.

5. The non-transitory computer-readable storage medium of claim 4 , wherein the comparand overlay data value comprises data to write to the selected bits identified by the comparand overlay pointer.

6. The non-transitory computer-readable storage medium of claim 1 , wherein the content addressable memory is searched with the modified comparand prior to reloading the comparand data register with a second comparand.

7. The non-transitory computer-readable storage medium of claim 1 , wherein a portion of the comparand comprises a table selector.

8. The non-transitory computer-readable storage medium of claim 7 , wherein the comparand overlay data value corresponds to the table selector of the comparand.

9. The non-transitory computer-readable storage medium of claim 1 , wherein the comparand overlay pointer specifies a location and a size of a comparand portion to be modified.

10. A system comprising

means for searching a content addressable memory based on a comparand, wherein the comparand is stored on a comparand data register, and wherein the comparand comprises a collection of bits;

means for receiving a comparand overlay pointer;

means for generating a modified comparand by modifying the comparand, wherein the modified comparand is based at least in part on a comparand overlay data value and the comparand overlay pointer; and

means for searching the content addressable memory with the modified comparand.

11. The system of claim 10 , wherein means for generating the modified comparand comprise modifying selected bits of the comparand.

12. The system of claim 11 , further comprising means for copying the comparand to a temporary comparand memory prior to modifying the selected bits of the comparand.

13. The system of claim 11 , wherein the comparand overlay pointer identifies the selected bits of the comparand to modify.

14. The system of claim 13 , wherein the comparand overlay data value comprises data to write to the selected bits identified by the comparand overlay pointer.

15. The system of claim 10 , wherein the content addressable memory is searched with the modified comparand prior to reloading the comparand data register with a second comparand.

16. The system of claim 10 , wherein a portion of the comparand comprises a table selector.

17. The system of claim 16 , wherein the comparand overlay data value corresponds to the table selector of the comparand.

18. The system of claim 10 , wherein the comparand overlay pointer specifies a location and a size of a comparand portion to be modified.

19. An apparatus comprising:

a comparand data register configured to store a comparand, wherein the comparand comprises a collection of bits;

a content addressable memory; and

a processor configured to:

search the content addressable memory based on the comparand;

receive a comparand overlay pointer; and

generate a modified comparand by modifying the comparand, wherein the modified comparand is based at least in part on a comparand overlay data value and the comparand overlay pointer.

20. The apparatus of claim 19 , wherein the processor is further configured to search the content addressable memory with the modified comparand.

21. The apparatus of claim 20 , wherein the content addressable memory is searched with the modified comparand prior to reloading the comparand data register with a second comparand.

22. The apparatus of claim 19 , wherein generating the modified comparand comprises modifying selected bits of the comparand.

23. The apparatus of claim 22 , wherein the processor is further configured to copy the comparand to a temporary comparand memory prior to modifying the selected bits of the comparand.

24. The apparatus of claim 22 , wherein the comparand overlay pointer identifies the selected bits of the comparand to modify.

25. The apparatus of claim 19 , wherein a portion of the comparand comprises a table selector.

26. The apparatus of claim 25 , wherein the comparand overlay data value corresponds to the table selector of the comparand.