Abstract: A method for detecting errors in a tag array includes accessing the tag array with an index, retrieving at least one tag from the tag array, and computing a parity bit based on the expected tag.

Abstract: Methods and apparatus are provided for sharing storage and execution resources between architectural units in a microprocessor using a polymorphic function unit. A method for executing instructions in a processor having a polymorphic execution unit includes the steps of reloading a state associated with a first instruction class and reconfiguring the polymorphic execution unit to operate in accordance with the first instruction class, when an instruction of the first instruction class is encountered and the polymorphic execution unit is configured to operate in accordance with a second instruction class. The method also includes the steps of reloading a state associated with a second instruction class and reconfiguring the polymorphic execution unit to operate in accordance with the second instruction class, when an instruction of the second instruction class is encountered and the polymorphic execution unit is configured to operate in accordance with the first instruction class.

Abstract: A polymorphic branch predictor and method includes a plurality of branch prediction methods. The methods are selectively enabled to perform branch prediction. A selection mechanism is configured to select one or more of the branch prediction methods in accordance with a dynamic setting to optimize performance of the branch predictor during operation in accordance with a current task.

Abstract: A method for detecting errors in a tag array includes accessing the tag array with an index, retrieving at least one tag from the tag array, and computing a parity bit based on the expected tag.

Abstract: There are provided methods and apparatus for multi-bit cell and SMT thread groups. An apparatus for a register file includes a plurality of multi-bit storage cells for storing a plurality of bits respectively corresponding to a plurality of threads. The apparatus further includes a plurality of port groups, operatively coupled to the plurality of multi-bit storage cells, responsive to physical register identifiers. The plurality of port groups is responsive to respective ones of a plurality of thread identifiers. Each of the plurality of thread identifiers are for uniquely identifying a particular thread from among a plurality of threads.

Abstract: There is provided a multi-bit storage cell for a register file. The storage cell includes a first set of storage elements for a vector slice. Each storage element respectively corresponds to a particular one of a plurality of thread sets for the vector slice. The storage cell includes a second set of storage elements for a scalar slice. Each storage element in the second set respectively corresponds to a particular one of at least one thread set for the scalar slice. The storage cell includes at least one selection circuit for selecting, for an instruction issued by a thread, a particular one of the storage elements from any of the first set and the second set based upon the instruction being a vector instruction or a scalar instruction and based upon a corresponding set from among the pluralities of thread sets to which the thread belongs.

Abstract: A polymorphic branch predictor and method includes a plurality of branch prediction methods. The methods are selectively enabled to perform branch prediction. A selection mechanism is configured to select one or more of the branch prediction methods in accordance with a dynamic setting to optimize performance of the branch predictor during operation in accordance with a current task.

Abstract: This invention pertains to apparatus, method and a computer program stored on a computer readable medium. The computer program includes instructions for use with an instruction unit having a code page, and has computer program code for partitioning the code page into at least two sections for storing in a first section thereof a plurality of instruction words and, in association with at least one instruction word, for storing in a second section thereof an extension to each instruction word in the first section. The computer program further includes computer program code for setting a state of at least one page table entry bit for indicating, on a code page by code page basis, whether the code page is partitioned into the first and second sections for storing instruction words and their extensions, or whether the code page is comprised instead of a single section storing only instruction words.

Abstract: This invention pertains to apparatus, method and a computer program stored on a computer readable medium. The computer program includes instructions for use with an instruction unit having a code page, and has computer program code for partitioning the code page into at least two sections for storing in a first section thereof a plurality of instruction words and, in association with at least one instruction word, for storing in a second section thereof an extension to each instruction word in the first section. The computer program further includes computer program code for setting a state of at least one page table entry bit for indicating, on a code page by code page basis, whether the code page is partitioned into the first and second sections for storing instruction words and their extensions, or whether the code page is comprised instead of a single section storing only instruction words.

Abstract: A pipeline system and method includes a plurality of operational stages. The stages include a pointer register stage which stores pointer information and updates, and a rename and dependence checking stage located downstream of the pointer register stage, which renames registers and determines if dependencies exist. A functional unit provides pointer information updates to the pointer register stage such that pointer information is processed and updated to the pointer register stage before or in parallel with the register dependency checking.

Abstract: A polymorphic branch predictor and method includes a plurality of branch prediction methods. The methods are selectively enabled to perform branch prediction. A selection mechanism is configured to select one or more of the branch prediction methods in accordance with a dynamic setting to optimize performance of the branch predictor during operation in accordance with a current task.

Abstract: A processing system and method includes a predecoder configured to identify instructions that are combinable. Instruction storage is configured to merge instructions that are combinable by replacing the combinable instructions with a wide data internal instruction for execution. An instruction execution unit is configured to execute the internal instruction on a wide datapath.

Abstract: A system and method for garbage collection in heterogeneous multiprocessor systems are provided. In some illustrative embodiments, garbage collection operations are distributed across a plurality of the processors in the heterogeneous multiprocessor system. Portions of a global mark queue are assigned to processors of the heterogeneous multiprocessor system along with corresponding chunks of a shared memory. The processors perform garbage collection on their assigned portions of the global mark queue and corresponding chunk of shared memory marking memory object references as reachable or adding memory object references to a non-local mark stack. The marked memory objects are merged with a global mark stack and memory object references in the non-local mark stack are merged with a “to be traced” portion of the global mark queue for re-checking using a garbage collection operation.

Abstract: The disclosed heterogeneous processor compresses information to more efficiently store the information in a system memory coupled to the processor. The heterogeneous processor includes a general purpose processor core coupled to one or more processor cores that exhibit an architecture different from the architecture of the general purpose processor core. In one embodiment, the processor dedicates a processor core other than the general purpose processor core to memory compression and decompression tasks. In another embodiment, system memory stores both compressed information and uncompressed information.

Abstract: A system, method, and computer program product are provided for performing scalar operations using a SIMD data parallel execution unit. With the mechanisms of the illustrative embodiments, scalar operations in application code are identified that may be executed using vector operations in a SIMD data parallel execution unit. The scalar operations are converted, such as by a static or dynamic compiler, into one or more vector load instructions and one or more vector computation instructions. In addition, control words may be generated to adjust the alignment of the scalar values for the scalar operation within the vector registers to which these scalar values are loaded using the vector load instructions. The alignment amounts for adjusting the scalar values within the vector registers may be statically or dynamically determined.

Abstract: A system, method and computer program product for supporting thread level speculative execution in a computing environment having multiple processing units adapted for concurrent execution of threads in speculative and non-speculative modes. Each processing unit includes a cache memory hierarchy of caches operatively connected therewith. The apparatus includes an additional cache level local to each processing unit for use only in a thread level speculation mode, each additional cache for storing speculative results and status associated with its associated processor when handling speculative threads. The additional local cache level at each processing unit are interconnected so that speculative values and control data may be forwarded between parallel executing threads. A control implementation is provided that enables speculative coherence between speculative threads executing in the computing environment.

Abstract: A system and method for executing instructions utilizing a preferred slot alignment mechanism is presented. A processor architecture uses a vector register file, a shared data path, and instruction execution logic to process both single instruction multiple data (SIMD) instruction and scalar instructions. The processor architecture divides a vector into four “slots,” each including four bytes, and locates scalar data in “preferred slots” to ensure proper positioning. Instructions using the preferred slot mechanism include 1) shift and rotate instructions operating across an entire quad-word that specify a shift amount, 2) memory load and store instructions that require an address, and 3) branch instructions that use the preferred slot for branch conditions (conditional branches) and branch addresses (register-indirect branches). As a result, the processor architecture eliminates the requirement for separate issue slots, separate pipelines, and the control complexity for separate scalar units.

Abstract: Methods and apparatus are provided for sharing storage and execution resources between architectural units in a microprocessor using a polymorphic function unit. A method for executing instructions in a processor having a polymorphic execution unit includes the steps of reloading a state associated with a first instruction class and reconfiguring the polymorphic execution unit to operate in accordance with the first instruction class, when an instruction of the first instruction class is encountered and the polymorphic execution unit is configured to operate in accordance with a second instruction class. The method also includes the steps of reloading a state associated with a second instruction class and reconfiguring the polymorphic execution unit to operate in accordance with the second instruction class, when an instruction of the second instruction class is encountered and the polymorphic execution unit is configured to operate in accordance with the first instruction class.

Abstract: A trace cache system is provided comprising a trace start address cache for storing trace start addresses with successor trace start addresses, a trace cache for storing traces of instructions executed, a trace history table (THT) for storing trace numbers in rows, a branch history shift register (BHSR) or a trace history shift register (THSR) that stores histories of branches or traces executed, respectively, a THT row selector for selecting a trace number row from the THT, the selection derived from a combination of a trace start address and history information from the BHSR or the THSR, and a trace number selector for selecting a trace number from the selected trace number row and for outputting the selected trace number as a predicted trace number.

Abstract: A method and apparatus for storing non-critical processor information without imposing significant costs on a processor design is disclosed. Transient data are stored in the processor-local cache hierarchy. An additional control bit forms part of cache addresses, where addresses having the control bit set are designated as “transient storage addresses.” Transient storage addresses are not written back to external main memory and, when evicted from the last level of cache, are discarded. Preferably, transient storage addresses are “privileged” in that they are either not accessible to software or only accessible to supervisory or administrator-level software having appropriate permissions. A number of management functions/instructions are provided to allow administrator/supervisor software to manage and/or modify the behavior of transient cache storage.