Abstract: Managing speculative execution via groups of one or more actions corresponding to atomic traces enables efficient processing of flag-related actions, as atomic traces advantageously enable single checkpoints of flag values at atomic trace boundaries. Checkpointing flags during atomic trace renaming in a processor system uses a flag checkpoint table to store a plurality of flag checkpoints, each corresponding to an atomic trace. The table is selectively accessed to provide flag information to restore speculative flags when an atomic trace is aborted. A corresponding flag checkpoint is stored when an atomic trace is renamed. An action that updates flags updates all entries in the table corresponding to younger atomic traces. If the atomic trace is aborted, then the corresponding flag checkpoint is used for restoration of flag state.

Abstract: Managing speculative execution via groups of actions corresponding to atomic traces enables efficient processing of flag-related actions, as atomic traces advantageously enable single checkpoints of flags at trace boundaries. Flag restoration from checkpoints for trace aborts uses a flag checkpoint table to store flag checkpoints, each corresponding to an atomic trace. The table is accessed for flag restoration in response to a trace abort. In a first technique, a corresponding flag checkpoint is stored in response to trace renaming, and the flag checkpoints are updated as flags are modified. Flags are restored from the flag checkpoint corresponding to an aborted atomic trace. In a second technique, a corresponding flag checkpoint is allocated to an invalid state in response to trace renaming, and initialized on-demand when flags are first modified in accordance with the atomic trace. Flags are restored from the oldest flag checkpoint starting from an aborted atomic trace.

Abstract: Managing speculative execution via groups of one or more actions corresponding to atomic traces enables efficient processing of flag-related actions, as atomic traces advantageously enable single checkpoints of flag values at atomic trace boundaries. Checkpointing flags on-demand for atomic traces in a processor system uses a flag checkpoint table to store a plurality of flag checkpoints, each corresponding to an atomic trace. The table is selectively accessed to provide flag information to restore speculative flags when an atomic trace is aborted. A corresponding flag checkpoint is allocated to an invalid state when an atomic trace is renamed. An action that updates flags initializes the corresponding flag checkpoint (if invalid). If the atomic trace is aborted, then the table is searched according to program order starting with the entry corresponding to the aborted atomic trace. The first (if any) valid checkpoint found is used for flag restoration.

Abstract: A method for synchronized renaming between a master processor and a coprocessor includes sending from the master processor an operation for execution by the coprocessor along with an identifier, at the coprocessor, renaming the operation for execution, including assigning a resource and associating the resource with the identifier, and at a subsequent time, sending the identifier from the master processor to the coprocessor to be used in conjunction with the execution of the renamed operation.

Abstract: Synchronized register renaming between a master processor and a coprocessor that receives operations from the master enables efficient implementation of register renaming and operation execution in the processors. An ideal and an external register allocation map are implemented in the coprocessor. When registers are no longer allocated according to the ideal allocation map and the registers are currently allocated according to the external allocation map, the registers are deallocated in the external map and the number of freed registers is reported to the master. The master increments a free register credit count accordingly, and decrements the credit count by one for each operation issued to the coprocessor. An operation is not issued to the coprocessor unless at least a register is free according to the credit count. The master also throttles coprocessor operation issue based on a credit count corresponding to free scheduler entries available in the coprocessor.

Abstract: An apparatus and a method dynamically reassign resources in a coprocessor among master processors that require service from the coprocessor. The method includes each processor, in each processor cycle, keeping track of a number of resource units required for executing operations sent to the coprocessor in that processor cycle and receiving from the coprocessor a number of resource units released during the processor cycle. When the resources need to be reassigned, the coprocessor asserts a signal to the resource yielding processor to cause it to reduce its expectation of resources to zero and ceasing sending service requests to the coprocessor. The coprocessor then moves resources from the yielding processor to the resource receiving processor. Resources are then released to both processors over time to their respective adjusted resource allocations. Such resources may be the number of operations that is allowed to be executing in the coprocessor simulataneously.

Abstract: An instruction stream having variable length instructions with embedded constants (e.g. immediate values and displacements) is translated into a stream of operations and a corresponding stream of bit fields, enabling advantageous compact storage of the embedded constants. The operations and the compact constants are optionally stored in entries in a trace cache and/or processed by execution pipelines. The compact constants are optionally formulated as a small constant field, a pointer, or both. The pointer of a particular one of the operations optionally references one of the bit fields within a window of the operations associated with the particular operation. A full-sized constant is constructed from one or more contiguous ones of the bit fields, starting with the referenced bit field, by unpacking and uncompressing information from the contiguous bit fields. An operation optionally includes a plurality of small constant fields and pointers to specify a respective plurality of constants.