536 results about "Program counter" patented technology

A system and method for program counter and data tracing is disclosed. A trace interface is provided for communication of trace information between a processor core and a trace control block. The trace interface enables various combinations of processor cores and trace control blocks to be implemented.

A fork instruction for execution on a multithreaded microprocessor and occupying a single instruction issue slot is disclosed. The fork instruction, executing in a parent thread, includes a first operand specifying the initial instruction address of a new thread and a second operand. The microprocessor executes the fork instruction by allocating context for the new thread, copying the first operand to a program counter of the new thread context, copying the second operand to a register of the new thread context, and scheduling the new thread for execution. If no new thread context is free for allocation, the microprocessor raises an exception to the fork instruction. The fork instruction is efficient because it does not copy the parent thread general purpose registers to the new thread. The second operand is typically used as a pointer to a data structure in memory containing initial general purpose register set values for the new thread.

A system and method for efficient improvement of branch prediction in a microprocessor with negligible impact on die-area, power consumption, and clock cycle period. It is determined if a program counter (PC) register contains a polymorphic indirect unconditional branch (PIUB) instruction. One determination may be searching a table with a portion or all of a PC of past PIUB instructions. If a hit occurs in this table, the global shift register (GSR) is updated by shifting a portion of the branch target address into the GSR, rather than updating the GSR with a taken/not-taken prediction bit. The stored value in the GSR is input into a hashing function along with the PC in order to index prediction tables such as a pattern history table (PHT), a branch target buffer (BTB), an indirect target array, or other. The updated value due to the PIUB instruction improves the accuracy of the prediction tables.

A computer system architecture in which each processor has its own memory, strategically distributed along the stages of an execution pipeline of the processor, to provide fast access to often used information, such as the contents of the address and data registers, the program counter, etc. Memory storage is strategically located in close physical proximity to a stage in an execution pipeline at which memory is commonly or repeatedly accessed. Coupled to the pipeline at various stages are small memory cells for storing information that is consistently and repeatedly requested at that stage in the execution pipeline. The speed of the execution pipeline in a processor is critical to overall performance of the processor and the computer architecture of the present invention as a whole. To that end, the clock cycle time at which the pipeline is operated is increased as much as the operating characteristics of the logic and associated circuitry will allow. Generally, access times for memory are slower than the clock cycle times at which the pipeline logic can operate. Thus, there is a point of diminishing return at which increasing the clock cycle time of the pipeline is less advantageous if the pipeline must wait for memory access to complete. Thus, there is provided two sets of strategically located memory cells distributed along the execution pipeline of a processor, and alternately accesses the memory cells.

A system, apparatus, and method for processing payment transactions that are conducted using a mobile payment device that includes a contactless element, such as an integrated circuit chip. The invention enables one or more of the operations of activation of a payment application, transfer of transaction data, updating of account records, setting or re-setting of a payment application counter or register, or transfer or processing of a script, command, or instruction, with these functions being performed with minimal impact on a consumer. This is accomplished by introducing a pre-tap and/or two-tap operation prior to, or as part of, the transaction flow.

A system and method for program counter and data tracing is disclosed. Generated trace messages are included within a trace word format and stored in trace memory, thereby enabling a reduction in the amount of trace storage required.

Embodiments of the present invention provide a method, apparatus and system of securing an operating system. The apparatus, according to some demonstrative embodiments of the invention, may include a memory access controller to receive from a processor a program counter representing a requested address of a memory to be accessed by the processor during a kernel mode of operation, and to selectively enable the processor to access the requested address based on a comparison between the requested address and one or more allowable addresses. Other embodiments are described and claimed.

A system and method are presented for saving and restoring the state of a diagnostic module in a microprocessor. The diagnostic module contains a complex break state machine, capable of halting the microprocessor at specified breakpoints. These breakpoints are based on combinations of instruction locations and/or data values, along with previous machine states. A problem occurs with prior art diagnostic modules when the processor returns from an exception occurring during a fix-up cycle inserted to handle a data load miss associated with an instruction located in a branch delay slot (the location immediately following a conditional branch instruction). Under these circumstances, the exception handler restores the program counter to the location of the branch instruction, causing the branch to be re-executed. The prior art state machine erroneously updates its internal state a second time when the branch is re-executed. According to the system and method disclosed herein, at each state change the previous machine state saved. Thus, when a branch instruction is re-executed, the complex break state machine of the present invention is restored to its previous state, thereby correcting the error.

In one embodiment of the present invention, a streaming multiprocessor (SM) uses a tree of nodes to manage threads. Each node specifies a set of active threads and a program counter. Upon encountering a conditional instruction that causes an execution path to diverge, the SM creates child nodes corresponding to each of the divergent execution paths. Based on the conditional instruction, the SM assigns each active thread included in the parent node to at most one child node, and the SM temporarily discontinues executing instructions specified by the parent node. Instead, the SM concurrently executes instructions specified by the child nodes. After all the divergent paths reconverge to the parent path, the SM resumes executing instructions specified by the parent node. Advantageously, the disclosed techniques enable the SM to execute divergent paths in parallel, thereby reducing undesirable program behavior associated with conventional techniques that serialize divergent paths across thread groups.

In one embodiment, an integrated circuit comprises a first processor configured to output program counter (PC) trace records, wherein PC trace records provide data indicating the PCs of instructions retired by the first processor. The integrated circuit further comprises a second source of trace records, and a trace unit coupled to receive the PC trace records from the first processor and the trace records from the second source. The trace unit comprises a trace memory into which the trace unit is configured to store the PC trace records and trace records from the second source. The trace unit is configured to interleave the PC trace records and the trace records from the second source in the trace memory according to the order of receipt of the records.

A system and method for program counter and data tracing is disclosed. The tracing mechanism of the present invention enables increased visibility into the hardware and software state of the processor core.

A system and a method to identify a conditional branch instruction having a program counter and a target address, and increment a loop count each time the program counter and the target address equal a stored program counter and a target address. The system and method additionally includes assignment of a start loop pointer and an end loop pointer, based on an offset, when the loop count is equal to a threshold value, and capturing instructions for a loop, as defined by the start loop pointer and the end loop pointer, in an instruction queue.

A method of acquiring software profile information of a target software application includes receiving a programmed interrupt while executing an application in a computer system, servicing the interrupt such that call stack information is acquired and processing the call stack information to produce statistical information concerning function calls. The call stack information includes program counter and other information which is derived from the target application as well as operating system. Some or all of the call stack information may be recorded. The statistical information includes statistics concerning the number of samples wherein a series of functions calls are included in the call stack information and the number of samples wherein a set of function calls are at the top of the call stack information.

Some demonstrative embodiments of the invention include a method, device and/or system of verifying that a secure code is executed by a processor. The device may include, for example, a memory to store a secure code; a processor intended to execute a gating code, wherein the gating code, when executed by the processor, results in the processor to perform at least one operation and set a program counter of the processor to point to an entry point of the secure code; and a verifier to verify that the processor had executed the gating code only if the processor performs the at least one operation. Other embodiments are described and claimed.

Disclosed is providing one of a plurality of schedulers for a multitasking system for a processor that includes choosing a particular one of the schedulers, setting a program counter to an address corresponding to code of the particular one of the schedulers, and the processor executing code at an address corresponding to the program counter. Also included may be setting a stack pointer to an address corresponding to stack space for the particular one of the schedulers and the processor using the stack space at the stack pointer after executing code at the address corresponding to the program counter. The system described herein provides a small kernel that can run on a variety of hardware platforms, such as a PowerPC based Symmetrix adapter board used in a Symmetrix data storage device provided by EMC Corporation of Hopkinton, Ma. The core kernel code may be written for the general target platform, such as the PowerPC architecture. Since the PowerPC implementation specific modules are well defined, the system may be quite portable between PowerPC processors (such as the 8260 and 750), and should prove relatively easy to port to any PowerPC based Symmetrix adapter board/CPU combination. The kernel may also be ported to run on other RISC machines (Hitachi SH series) and can be ported to CISC architectures.