摘要:
When an abort of a transaction occurs, a determination is made as to whether diagnostic information is to be stored in one or more transaction diagnostic blocks (TDBs). There are different types of transaction diagnostic blocks to accept diagnostic information depending on the type of abort and other considerations. As examples, there are a program-specified TDB in which information is stored if a valid TDB address is provided in a transaction begin instruction; a program interruption TDB, which is stored into when the program is aborted due to an interruption; and a program interception TDB, which is stored into when an abort results in an interception.
摘要:
An operation is provided to signal a processor that action is to be taken to facilitate execution of a transaction that has aborted one or more times. The operation is specified within an instruction or is itself an instruction. The instruction is executed based on detecting an abort of the transactions, and includes a field indicating how many times the transaction has aborted. The processor uses this information to determine what action is to be taken.
摘要:
A TRANSACTION ABORT instruction is used to abort a transaction that is executing in a computing environment. The TRANSACTION ABORT instruction includes at least one field used to specify a user-defined abort code that indicates the specific reason for aborting the transaction. Based on executing the TRANSACTION ABORT instruction, a condition code is provided that indicates whether re-execution of the transaction is recommended.
摘要:
A TRANSACTION BEGIN instruction begins execution of a transaction and includes a general register save mask having bits, that when set, indicate registers to be saved in the event the transaction is aborted. At the beginning of the transaction, contents of the registers are saved in memory not accessible to the program, and if the transaction is aborted, the saved contents are copied to the registers.
摘要:
Execution of instructions in a transactional environment is selectively controlled. A TRANSACTION BEGIN instruction initiates a transaction and includes controls that selectively indicate whether certain types of instructions are permitted to execute within the transaction. The controls include one or more of an allow access register modification control and an allow floating point operation control.
摘要:
A Load to Block Boundary instruction is provided that loads a variable number of bytes of data into a register while ensuring that a specified memory boundary is not crossed. The boundary may be specified a number of ways, including, but not limited to, a variable value in the instruction text, a fixed instruction text value encoded in the opcode, or a register based boundary.
摘要:
A non-quiescing key setting facility is provided that enables manipulation of storage keys to be performed without quiescing operations of other processors of a multiprocessor system. With this facility, a storage key, which is accessible by a plurality of processors of the multiprocessor system, is updated absent a quiesce of operations of the plurality of processors. Since the storage key is updated absent quiescing of other operations, the storage key may be observed by a processor as having one value at the start of an operation performed by the processor and a second value at the end of the operation. A mechanism is provided to enable the operation to continue, avoiding a fatal exception.
摘要:
A system for data operand fetching control includes a computer processor that includes a control unit for determining memory access operations. The control unit is configured to perform a method. The method includes calculating a summation weight value for each instruction in a pipeline, the summation weight value calculated as a function of branch uncertainty and a pendency in which the instruction resides in the pipeline relative to other instructions in the pipeline. The method also includes mapping the summation weight value of a selected instruction that is attempting to access system memory to a memory access control, each memory access control specifying a manner of handling data fetching operations. The method further includes performing a memory access operation for the selected instruction based upon the mapping.
摘要:
A method, information processing system, and computer program product manage variable operand length instructions. At least one variable operand length instruction is received. The at least one variable operand length instruction is analyzed. A length of at least one operand in the variable operand length instruction is identified based on the analyzing. The at least one variable operand length instruction is organized into a set of unit of operations. The set of unit of operations are executed. The executing increases one or more performance metrics of the at least one variable operand length instruction.
摘要:
A method and information processing system manage load and store operations executed out-of-order. At least one of a load instruction and a store instruction is executed. A determination is made that an operand store compare hazard has been encountered. An entry within an operand store compare hazard prediction table is created based on the determination. The entry includes at least an instruction address of the instruction that has been executed and a hazard indicating flag associated with the instruction. The hazard indicating flag indicates that the instruction has encountered the operand store compare hazard. When a load instruction is associated with the hazard indicating flag the load instruction becomes dependent upon all store instructions associated with a substantially similar flag.