US 8,572,341 B2Granted

Overflow handling of speculative store buffers

AssigneeInternational Business Machines Corporation

InventorsColin B. Blundell, Harold Wade Cain, III, Gheorghe C. Cascaval, Maged Milad Michael

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Abstract

A method, a system and a computer program product for handling speculative stores. The system determines when a speculative store buffer is not full. An indicator is generated when the speculative store buffer is not full, and the speculative stores are input into the speculative store buffer. When the speculative store buffer is full, a full buffer indicator is generated. Speculative stores prevented from entering the speculative store buffer are overflow stores. The overflow list is searched to determine whether one or more addresses of the overflow stores are present in the overflow list. When one or more addresses of the overflow stores are not present in the overflow list, the overflow stores are stored in the overflow list.

Claims19

Dependent claims

In a processor having a speculative store buffer a method for handling speculative stores, said method comprising:

processor logic determining when the speculative store buffer is not at full capacity;
storing one or more speculative stores in the speculative store buffer in response to the speculative store buffer not being at full capacity;
dynamically generating a full capacity indicator in response to the speculative store buffer being loaded to full capacity;
responsive to a subsequent receipt of one or more overflow speculative stores when the speculative store buffer is at full capacity, storing the one or more of the overflow speculative stores in an overflow list of overflow speculative stores;
associating the speculative store buffer with the overflow list of overflow speculative stores, wherein the overflow list of overflow speculative stores holds one or more previous overflow stores;
generating the overflow list of overflow speculative stores, wherein one or more overflow speculative stores are loaded into the overflow list of overflow speculative stores;
determining when the overflow list of overflow speculative stores is empty;
and
in response to the overflow list of overflow speculative stores not being empty, searching the overflow list of overflow speculative stores for a previously stored overflow address that is identical to an address of the one or more overflow speculative stores.

6 more elements

A computer system for handling speculative stores, said computer system comprising:

a processor component;
and
logic associated with the processor component that configures the computer system to:
determine when a speculative store buffer is not at full capacity;
store one or more speculative stores in the speculative store buffer in response to the speculative store buffer not being at full capacity;
dynamically generate a first indicator in response to the speculative store buffer being loaded to full capacity, wherein the first indicator is a full capacity indicator;
responsive to a subsequent receipt of one or more overflow speculative stores when the speculative store buffer is at full capacity, dynamically compare a speculative store address of the one or more overflow stores to one or more previously stored overflow address in the overflow list of speculative stores and store the one or more of the overflow speculative stores in an overflow list of overflow speculative store.

4 more elements

A computer program product comprising:

a non-transitory computer readable storage device;
and
program code on the non-transitory computer readable storage device that when executed by a processor provides the functions of:
determining when a speculative store buffer is not at full capacity;
storing one or more speculative stores in the speculative store buffer in response to the speculative store buffer not being at full capacity;
dynamically generating a first indicator in response to the speculative store buffer being loaded to full capacity, wherein the first indicator is a full capacity indicator;
responsive to a subsequent receipt of one or more overflow speculative stores when the speculative store buffer is at full capacity, storing the one or more of the overflow speculative stores in an overflow list of overflow speculative stores;
associating the speculative store buffer with the overflow list of overflow speculative stores wherein the overflow list of overflow speculative stores holds one or more previous overflow stores;
generating the overflow list of overflow speculative stores, wherein one or more overflow speculative stores are loaded into the overflow list of overflow speculative stores;
determining when the overflow list of overflow speculative stores is empty;
and
in response to the overflow list of overflow speculative stores not being empty, searching the overflow list of overflow speculative stores for a previously stored overflow address that is identical to an address of the one or more overflow speculative stores.

9 more elements

Dependencies are inferred from the claim text.