Abstract: A clothesline system comprises at least two separate cables that are independently tensionable through separate cable tensioning devices. The tension devices are attached together to provide for common, parallel movement of the separate cables though the cables are separately passed around separate pulleys at the both ends of the system. The two separate cables add strength to the system. The separate cables are preferably wound in left and right windings to prevent unraveling of the braid of the cable. By providing separate cables, assembly of the system is less complex as the two loops of cable are separate.

Abstract: A system that facilitates improving performance of a processor during scout mode. During a normal-execution mode, the system executes instructions for using main thread. Upon encountering a stall condition during execution of the main thread, the system generates a checkpoint. The system then enters a scout mode, wherein instructions are speculatively executed by a speculative thread to prefetch future memory references, but results are not committed to the architectural state of the processor. Upon encountering a memory reference during scout mode, the system issues a prefetch for the memory reference. If the stall condition that caused the processor to enter scout mode is resolved, the system uses the checkpoint to resume execution of the main thread from the instruction that caused the stall condition, and simultaneously continues executing instructions in scout mode using the speculative thread from the point where the speculative thread left off.

Abstract: A technique recovers return address stack (RAS) content and restores alignment of a RAS top-of-stack (TOS) pointer for occurrences of mispredictions due to speculative operation, out-of-order instruction processing, and exception handling. In at least one embodiment of the invention, an apparatus includes a speculative execution processor pipeline, a first structure for maintaining return addresses relative to instruction flow at a first stage of the pipeline, at least a second structure for maintaining return addresses relative to instruction flow at a second stage of the pipeline. The second stage of the pipeline is deeper in the pipeline than the first stage. The apparatus includes circuitry operable to reproduce at least return addresses from the second structure to the first structure.

Abstract: By encoding an exception triggering value in storage referenced by an instruction in an otherwise unused slot (e.g., the delay slot of a delayed control transfer instruction or an unused instruction position in a VLIW-based architecture) coinciding with a safe point, an efficient coordination mechanism can be provided for multi-threaded code. Because the mechanism(s) impose negligible overhead when not employed and can be engaged in response to an event (e.g., a start garbage collection event), safe points can be defined at call, return and/or backward branch points throughout mutator code to reduce the latency between the event and suspension of all threads. Though particularly advantageous for thread suspension to perform garbage collection at safe points, the techniques described herein are more generally applicable to program suspension at coordination points coinciding with calls, returns, branches or calls, returns and branches therein.

Abstract: A register file, in a processor, includes a first plurality of registers of a first size, n-bits. A decoder uses a mapping that divides the register file into a second plurality M of registers having a second size. Each of the registers having the second size is assigned a different name in a continuous name space. Each register of the second size includes a plurality N of registers of the first size, n-bits. Each register in the plurality N of registers is assigned the same name as the register of the second size that includes that plurality. State information is maintained in the register file for each n-bit register. The dependence of an instruction on other instructions is detected through the continuous name space. The state information allows the processor to determine when the information in any portion, or all, of a register is valid.

Abstract: One embodiment of the present invention provides a system that selectively monitors store instructions to support transactional execution of a process, wherein changes made during the transactional execution are not committed to the architectural state of a processor until the transactional execution successfully completes. Upon encountering a store instruction during transactional execution of a block of instructions, the system determines whether the store instruction is a monitored store instruction or an unmonitored store instruction. If the store instruction is a monitored store instruction, the system performs the store operation, and store-marks a cache line associated with the store instruction to facilitate subsequent detection of an interfering data access to the cache line from another process. If the store instruction is an unmonitored store instruction, the system performs the store operation without store-marking the cache line.

Abstract: A processor includes a device providing a throttling power output signal. The throttling power output signal is used to determine when to logically throttle the power consumed by the processor. At least one core in the processor includes a pipeline having a decode pipe; and a logical power throttling unit coupled to the device to receive the output signal, and coupled to the decode pipe. Following the logical power throttling unit receiving the power throttling output signal satisfying a predetermined criterion, the logical power throttling unit causes the decode pipe to reduce an average number of instructions decoded per processor cycle without physically changing the processor cycle or any processor supply voltages.

Abstract: A computer processor pipeline has both an architectural register file and a working register file. The lifetime of an entry in the working register file is determined by a predetermined number of instructions passing through a specified stage in the pipeline after the location in the working register file is allocated for an instruction. The size of the working register file is selected based upon performance characteristics. A working register file creditor indicator is coupled to the front end pipeline portion and to the back end pipeline portion. The working register file credit indicator is monitored to prevent a working register file overflow. When the a location in the architectural register file is read early, the location is monitored to determine whether the location is written to prior to issuance of the instruction associated with the early read.

Abstract: A user is provided with means to sample memory hierarchy via software. This allows a user to enhance memory-level parallelism via software. A status of information needed for execution of a second computer program instruction is read in response to execution of a first computer program instruction. Execution continues with execution of the second computer program instruction upon the status being a first status. Alternatively, a third computer program instruction is executed upon the status being a second status different from the first status. Thus, execution of the first computer program instruction allows control of the memory hierarchy, which in turn give the user control of the memory hierarchy.

Abstract: Embodiments of the present invention provide a system that facilitates executing a memory barrier (membar) instruction in an execute-ahead processor, wherein the membar instruction forces buffered loads and stores to complete before allowing a following instruction to be issued.

Abstract: Object simulation and interaction of and between computer-generated or graphical objects in a virtual space includes neutral scene graphs, data structures and procedures for using such graphs and data structures.

Abstract: Embodiments of the present invention provide a system that executes program code in a processor. The system starts by executing the program code in a normal mode using a primary strand while concurrently executing the program code ahead of the primary strand using a subordinate strand in a scout mode. Upon resolving a branch using the subordinate strand, the system records a resolution for the branch in a speculative branch resolution table. Upon subsequently encountering the branch using the primary strand, the system uses the recorded resolution from the speculative branch resolution table to predict a resolution for the branch for the primary strand. Upon determining that the resolution of the branch was mispredicted for the primary strand, the system determines that the subordinate strand mispredicted the branch. The system then recovers the subordinate strand to the branch and restarts the subordinate strand executing the program code.

Abstract: Embodiments of the present invention provide a system that executes program code in a processor. The system starts by executing the program code in a normal mode using a primary strand while concurrently executing the program code ahead of the primary strand using a subordinate strand in a scout mode. Upon resolving a branch using the subordinate strand, the system records a resolution for the branch in a speculative branch resolution table. Upon subsequently encountering the branch using the primary strand, the system uses the recorded resolution from the speculative branch resolution table to predict a resolution for the branch for the primary strand. Upon determining that the resolution of the branch was mispredicted for the primary strand, the system determines that the subordinate strand mispredicted the branch. The system then recovers the subordinate strand to the branch and restarts the subordinate strand executing the program code.

Abstract: Embodiments of the present invention provide a system for executing program code on a processor. In these embodiments, the processor is configured to start by using a primary strand to execute program code. Upon detecting a predetermined condition, the processor is configured to instantaneously checkpoint an architectural state of the primary strand and then use the subordinate strand to copy the checkpointed state to memory while using the primary strand to continue executing the program code without interruption.

Abstract: One embodiment of the present invention provides a system which performs simultaneous speculative threading. The system staffs by executing instructions in normal execution mode using a first thread. Upon encountering a data-dependent stall condition, the first thread generates an architectural checkpoint and commences execution of instructions in execute-ahead mode. During execute-ahead mode, the first thread executes instructions that can be executed and defers instructions that cannot be executed into a deferred queue. When the data dependent stall condition has been resolved, the first thread generates a speculative checkpoint and continues execution in execute-ahead mode. At the same time, the second thread commences execution in a deferred mode. During execution in the deferred mode, the second thread executes instructions deferred by the first thread.

Abstract: Architectural techniques and implementations that defer enforcement of certain delayed control transfer instruction (DCTI) sequencing constraints or conventions to later stages of an execution pipeline are described. In this way, complexity of a processor pipeline front-end (including fetch sequencing) can be simplified, at least in-part, by fetching instructions generally without regard to such constraints or conventions. Instead, enforcement of such sequencing constraints and/or conventions may be deferred to one or more pipeline stages associated with commitment or retirement of instructions. Higher fetch bandwidth may be achieved in some realizations when, for example, DCTI couples are encountered in an execution sequence.

Abstract: One embodiment of the present invention provides a system that prevents data hazards during simultaneous speculative threading. The system starts by executing instructions in an execute-ahead mode using a first thread. While executing instructions in the execute-ahead mode, the system maintains dependency information for each register indicating whether the register is subject to an unresolved data dependency. Upon the resolution of a data dependency during execute-ahead mode, the system copies dependency information to a speculative copy of the dependency information. The system then commences execution of the deferred instructions in a deferred mode using a second thread.

Abstract: Embodiments of the present invention provide a system that executes a transaction on a simultaneous speculative threading (SST) processor. In these embodiments, the processor includes a primary strand and a subordinate strand. Upon encountering a transaction with the primary strand while executing instructions non-transactionally, the processor checkpoints the primary strand and executes the transaction with the primary strand while continuing to non-transactionally execute deferred instructions with the subordinate strand. When the subordinate strand non-transactionally accesses a cache line during the transaction, the processor updates a record for the cache line to indicate the first strand ID. When the primary strand transactionally accesses a cache line during the transaction, the processor updates a record for the cache line to indicate a second strand ID.

Abstract: A processor reduces wasted cycle time resulting from stalling and idling, and increases the proportion of execution time, by supporting and implementing both vertical multithreading and horizontal multithreading. Vertical multithreading permits overlapping or “hiding” of cache miss wait times. In vertical multithreading, multiple hardware threads share the same processor pipeline. A hardware thread is typically a process, a lightweight process, a native thread, or the like in an operating system that supports multithreading. Horizontal multithreading increases parallelism within the processor circuit structure, for example within a single integrated circuit die that makes up a single-chip processor. To further increase system parallelism in some processor embodiments, multiple processor cores are formed in a single die. Advances in on-chip multiprocessor horizontal threading are gained as processor core sizes are reduced through technological advancements.

Abstract: A method and apparatus for efficiently performing graphic operations are provided. This is accomplished by providing a processor that supports any combination of the following instructions: parallel multiply-add, conditional pick, parallel averaging, parallel power, parallel reciprocal square root and parallel shifts.