Promoting and appending traces in an instruction processing circuit based upon a bias value

1. A method for promoting a trace in a microprocessor instruction processing circuit comprising:

a) determining if a current trace is promotable based upon a bias;

b) determining if a next trace is appendable to the current trace; and

c) promoting the current trace and the next trace if the current trace is promotable and the next trace is appendable,

wherein an initial bias is set based upon a set of conditions comprising:

sequencing type,

CS bad segment,

non-promotable, and

non-speculative.

2. The method of claim 1 , wherein steps (a), (b) and (c) are repeated until either the current trace is not promotable or the next trace is not appendable.

3. The method of claim 1 , wherein the promoting step (c) includes marking the current trace as promoted and the next trace as promoted if the current trace is promotable and the next trace is appendable.

4. The method of claim 1 , wherein the current trace and the next trace are promoted together.

5. The method of claim 1 , wherein the current trace and the next trace can be a basic block trace or a multi block trace.

6. The method of claim 1 , wherein the current trace is determined to be promotable based upon a last branch direction.

7. The method of claim 1 , wherein the next trace is determined to be appendable based upon a set of conditions that includes one or more of the following:

a) a maximum number of ops;

b) a maximum number of internal branches;

c) an encoded trace;

d) a maximum number of interior new ip asserts;

e) a maximum number of unique PTB pointers;

f) an allowed modification action to the call return stack (CRS);

g) a maximum offset for a return address to push onto the CRS; and

h) an unrolling of loops.

8. The method of claim 1 , wherein based upon the bias comprises:

comparing the bias to a promotion threshold.

9. The method of claim 8 , wherein the promotion threshold is dynamically adjustable.

10. The method of claim 1 , wherein the bias comprises a number of times a branch has been consistently taken in the same direction.

11. The method of claim 1 , wherein the bias represents one of a plurality of trace attributes, wherein each trace attribute indicates whether a current trace is not promotable or not appendable.

12. The method of claim 11 , wherein the plurality of trace attributes include non-promotable, CS bad segment, CS bad segment non-speculative, and non-speculative.

13. The method of claim 11 , wherein at least one of the trace attributes can be changeable.

14. The method of claim 11 , wherein at least one of the trace attributes can be removed from the trace.

15. The method of claim 6 , wherein the based upon a last branch direction comprises determining if the last branch direction is equal to the current branch prediction.