BRANCH PREDICTION USING MULTI-WAY PATTERN HISTORY TABLE (PHT) AND GLOBAL PATH VECTOR (GPV)
First Claim
1. A computer implemented method for branch prediction using a multi-way pattern history table (PHT) that is indexed using a global path vector (GPV), the method comprising:
- receiving a search address by a branch prediction logic that is in communication with the PHT and the GPV;
starting with the search address, simultaneously determining a plurality of branch predictions by the branch prediction logic based on the PHT, wherein the plurality of branch predictions comprises one of;
(i) at least one not taken prediction and a single taken prediction, and (ii) a plurality of not taken predictions; and
updating the GPV by shifting an instruction identifier of a branch instruction associated with a taken prediction into the GPV, wherein the GPV is not updated based on any not taken prediction.
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Abstract
Embodiments relate to branch prediction using a pattern history table (PHT) that is indexed using a global path vector (GPV). An aspect includes receiving a search address by a branch prediction logic that is in communication with the PHT and the GPV. Another aspect includes starting with the search address, simultaneously determining a plurality of branch predictions by the branch prediction logic based on the PHT, wherein the plurality of branch predictions comprises one of: (i) at least one not taken prediction and a single taken prediction, and (ii) a plurality of not taken predictions. Another aspect includes updating the GPV by shifting an instruction identifier of a branch instruction associated with a taken prediction into the GPV, wherein the GPV is not updated based on any not taken prediction.
18 Citations
15 Claims
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1. A computer implemented method for branch prediction using a multi-way pattern history table (PHT) that is indexed using a global path vector (GPV), the method comprising:
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receiving a search address by a branch prediction logic that is in communication with the PHT and the GPV; starting with the search address, simultaneously determining a plurality of branch predictions by the branch prediction logic based on the PHT, wherein the plurality of branch predictions comprises one of;
(i) at least one not taken prediction and a single taken prediction, and (ii) a plurality of not taken predictions; andupdating the GPV by shifting an instruction identifier of a branch instruction associated with a taken prediction into the GPV, wherein the GPV is not updated based on any not taken prediction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer program product for implementing branch prediction using a multi-way pattern history table (PHT) that is indexed using a global path vector (GPV), the computer program product comprising:
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a computer readable storage medium having program instructions embodied therewith, the program instructions readable by a processing circuit to cause the processing circuit to perform a method comprising; receiving a search address by a branch prediction logic that is in communication with the PHT and the GPV; starting with the search address, simultaneously determining a plurality of branch predictions by the branch prediction logic based on the PHT, wherein the plurality of branch predictions comprises one of;
(i) at least one not taken prediction and a single taken prediction, and (ii) a plurality of not taken predictions; andupdating the GPV by shifting an instruction identifier of a branch instruction associated with a taken prediction into the GPV, wherein the GPV is not updated based on any not taken prediction. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification