Abstract: Embodiments related to managing lazy runahead operations at a microprocessor are disclosed. For example, an embodiment of a method for operating a microprocessor described herein includes identifying a primary condition that triggers an unresolved state of the microprocessor. The example method also includes identifying a forcing condition that compels resolution of the unresolved state. The example method also includes, in response to identification of the forcing condition, causing the microprocessor to enter a runahead mode.

Abstract: Embodiments related to re-dispatching an instruction selected for re-execution from a buffer upon a microprocessor re-entering a particular execution location after runahead are provided. In one example, a microprocessor is provided. The example microprocessor includes fetch logic, one or more execution mechanisms for executing a retrieved instruction provided by the fetch logic, and scheduler logic for scheduling the retrieved instruction for execution. The example scheduler logic includes a buffer for storing the retrieved instruction and one or more additional instructions, the scheduler logic being configured, upon the microprocessor re-entering at a particular execution location after runahead, to re-dispatch, from the buffer, an instruction that has been previously dispatched to one of the execution mechanisms.

Abstract: Various embodiments of microprocessors and methods of operating a microprocessor during runahead operation are disclosed herein. One example method of operating a microprocessor includes identifying a runahead-triggering event associated with a runahead-triggering instruction and, responsive to identification of the runahead-triggering event, entering runahead operation and inserting the runahead-triggering instruction along with one or more additional instructions in a queue. The example method also includes resuming non-runahead operation of the microprocessor in response to resolution of the runahead-triggering event and re-dispatching the runahead-triggering instruction along with the one or more additional instructions from the queue to the execution logic.

Abstract: Embodiments related to managing potentially invalid results generated/obtained by a microprocessor during runahead are provided. In one example, a method for operating a microprocessor includes causing the microprocessor to enter runahead upon detection of a runahead event. The example method also includes, during runahead, determining that an operation associated with an instruction referencing a storage location would produce a potentially invalid result based on a value of an architectural poison bit associated with the storage location and performing a different operation in response.

Abstract: Embodiments related to managing lazy runahead operations at a microprocessor are disclosed. For example, an embodiment of a method for operating a microprocessor described herein includes identifying a primary condition that triggers an unresolved state of the microprocessor. The example method also includes identifying a forcing condition that compels resolution of the unresolved state. The example method also includes, in response to identification of the forcing condition, causing the microprocessor to enter a runahead mode.

Abstract: Embodiments related to managing lazy runahead operations at a microprocessor are disclosed. For example, an embodiment of a method for operating a microprocessor described herein includes identifying a primary condition that triggers an unresolved state of the microprocessor. The example method also includes identifying a forcing condition that compels resolution of the unresolved state. The example method also includes, in response to identification of the forcing condition, causing the microprocessor to enter a runahead mode.

Abstract: Various embodiments of microprocessors and methods of operating a microprocessor during runahead operation are disclosed herein. One example method of operating a microprocessor includes identifying a runahead-triggering event associated with a runahead-triggering instruction and, responsive to identification of the runahead-triggering event, entering runahead operation and inserting the runahead-triggering instruction along with one or more additional instructions in a queue. The example method also includes resuming non-runahead operation of the microprocessor in response to resolution of the runahead-triggering event and re-dispatching the runahead-triggering instruction along with the one or more additional instructions from the queue to the execution logic.

Abstract: Embodiments related to managing lazy runahead operations at a microprocessor are disclosed. For example, an embodiment of a method for operating a microprocessor described herein includes identifying a primary condition that triggers an unresolved state of the microprocessor. The example method also includes identifying a forcing condition that compels resolution of the unresolved state. The example method also includes, in response to identification of the forcing condition, causing the microprocessor to enter a runahead mode.

Abstract: Embodiments related to methods and devices operative, in the event that execution of an instruction produces a runahead-triggering event, to cause a microprocessor to enter into and operate in a runahead without reissuing the instruction are provided. In one example, a microprocessor is provided. The example microprocessor includes fetch logic for retrieving an instruction, scheduling logic for issuing the instruction retrieved by the fetch logic for execution, and runahead control logic. The example runahead control logic is operative, in the event that execution of the instruction as scheduled by the scheduling logic produces a runahead-triggering event, to cause the microprocessor to enter into and operate in a runahead mode without reissuing the instruction, and carry out runahead policies while the microprocessor is in the runahead mode that governs operation of the microprocessor and cause the microprocessor to operate differently than when not in the runahead mode.

Abstract: Embodiments related to managing potentially invalid results generated/obtained by a microprocessor during runahead are provided. In one example, a method for operating a microprocessor includes causing the microprocessor to enter runahead upon detection of a runahead event. The example method also includes, during runahead, determining that an operation associated with an instruction referencing a storage location would produce a potentially invalid result based on a value of an architectural poison bit associated with the storage location and performing a different operation in response.

Abstract: Embodiments related to re-dispatching an instruction selected for re-execution from a buffer upon a microprocessor re-entering a particular execution location after runahead are provided. In one example, a microprocessor is provided. The example microprocessor includes fetch logic, one or more execution mechanisms for executing a retrieved instruction provided by the fetch logic, and scheduler logic for scheduling the retrieved instruction for execution. The example scheduler logic includes a buffer for storing the retrieved instruction and one or more additional instructions, the scheduler logic being configured, upon the microprocessor re-entering at a particular execution location after runahead, to re-dispatch, from the buffer, an instruction that has been previously dispatched to one of the execution mechanisms.

Abstract: A method and apparatus for a burst mode write in a shared bus architecture comprising detecting a write data burst, determining if at least one memory unit is available to receive the write data burst, writing the write data burst to the at least one memory unit if the at least one memory unit is available to receive data. Storing a first portion of the write data burst in a buffer, concurrently with activating the at least one memory unit to receive data, if the at least one memory unit is not available to receive data; writing a second portion of the write data burst to the at least one memory unit when the at least one memory unit is available to receive data, and writing the first portion of the write data burst from the buffer to the at least one memory unit after writing the second portion of the write data burst.