Abstract: A Spin Loop Delay instruction. The instruction has a field associated therewith that indicates one or more conditions to be checked. Dispatching of the instruction is initially delayed. The instruction is subsequently dispatched based on a timeout, provided the instruction has not been previously dispatched based on meeting at least one condition of the one or more conditions to be checked.

Abstract: An instruction stream includes a transactional code region. The transactional code region includes a latent modification instruction (LMI), a next sequential instruction (NSI) following the LMI, and a set of target instructions following the NSI in program order. Each target instruction has an associated function, and the LMI at least partially specifies a substitute function for the associated function. A processor executes the LMI, the NSI, and at least one of the target instructions, employing the substitute function at least partially specified by the LMI. The LMI, the NSI, and the target instructions may be executed by the processor in sequential program order or out of order.

Abstract: Prevention of a prefetch memory operation from causing a transaction to abort. A local processor receives a prefetch request from a remote processor. A processor determines whether the prefetch request conflicts with a transaction of the local processor. A processor responds to at least one of i) a determination that the local processor has no transaction, and ii) a determination that the prefetch request does not conflict with a transaction by providing a requested prefetch data by providing a requested prefetch data. A processor responds to a determination that the prefetch request conflicts with a transaction by suppressing a processing of the prefetch request.

Abstract: An instruction stream includes a transactional code region. The transactional code region includes a latent modification instruction (LMI), a next sequential instruction (NSI) following the LMI, and a set of target instructions following the NSI in program order. Each target instruction has an associated function, and the LMI at least partially specifies a substitute function for the associated function. A processor executes the LMI, the NSI, and at least one of the target instructions, employing the substitute function at least partially specified by the LMI. The LMI, the NSI, and the target instructions may be executed by the processor in sequential program order or out of order.

Abstract: One aspect is a method that includes analyzing, by a processor of an analysis system, an instruction set architecture of a targeted complex-instruction set computer (CISC) processor to generate an instruction set profile for each CISC architectural instruction variant of the instruction set architecture. A combination of instruction sequences for the targeted CISC processor is determined from the instruction set profile that corresponds to a desired stressmark type. The desired stressmark type defines a metric representative of functionality of interest of the targeted CISC processor. Performance of the targeted CISC processor is monitored with respect to the desired stressmark type while executing each of the instruction sequences. The targeted CISC processor is stress tested based on executing at least one of the instruction sequences identified as most closely aligning with the desired stressmark type.

Abstract: Prevention of a prefetch memory operation from causing a transaction to abort. A local processor receives a prefetch request from a remote processor. A processor determines whether the prefetch request conflicts with a transaction of the local processor. A processor responds to at least one of i) a determination that the local processor has no transaction, and ii) a determination that the prefetch request does not conflict with a transaction by providing a requested prefetch data by providing a requested prefetch data. A processor responds to a determination that the prefetch request conflicts with a transaction by suppressing a processing of the prefetch request.

Abstract: An aspect includes fetching a computer instruction, the fetching by an instruction fetch unit. It is determined that the instruction is a decimal divide instruction that specifies a decimal divisor and a decimal dividend. The decimal divisor is converted into a floating-point divisor and the decimal dividend is converted into a floating-point dividend. A floating-point division of the floating-point dividend by the floating-point divisor is performed by an instruction execution unit. It is determined that the floating-point division resulted in a quotient overflow. A reduced size floating-point dividend is generated based on the quotient overflow, the floating-point divisor, and the floating-point dividend. The floating point division of the reduced size floating-point dividend by the floating-point divisor is performed by the instruction execution unit, and a specified number of rightmost bits of the result is output as the quotient.

Abstract: Testing for pending external interruptions. A Test Pending External Interruption instruction tests for pending external interruptions. The test for pending external interruptions is based on one or more program-specified subclasses, regardless of whether the machine is enabled for those classes of interruption. The instruction provides an indication for those subclasses being tested of whether there are any pending external interruptions for those subclasses.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: An instruction to perform a conditional branch to an indirectly specified location is executed. A branch address is obtained from a location in memory, the location in memory designated by the instruction. A determination is made, based on a condition code of another instruction, whether a branch is to occur, and a branch to the branch address is performed, based on determining the branch is to occur.

Abstract: A clock comparator sign control is used in a compare operation. A clock comparator sign control that determines whether unsigned arithmetic or signed arithmetic is to be used in a comparing operation is obtained. The clock comparator sign control is then used in a comparison of a value of a clock comparator and at least a portion of a value of a time-of-day clock to determine whether a selected action is to be recognized.

Abstract: In an approach for resolving terminated transactions in a transactional memory environment, a processor initiates a hardware transaction in a computing environment, wherein the hardware transaction accesses a memory location, and wherein the hardware transaction includes a transaction begin indicator and a transaction end indicator. A processor detects a conflicting access of the memory location while executing the hardware transaction. A processor aborts the hardware transaction based on the conflicting access of the memory location. Hardware determines that the conflicting access of the memory location is a transient condition. A processor reinitiates the hardware transaction.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: A guarded storage facility sets up a boundary indicating a range of addresses to be guarded or protected. When a program attempts to access an address in a guarded section defined by the boundary, a guarded storage event occurs. Use of this facility facilitates performance of certain tasks within a computing environment, including storage reclamation.

Abstract: Determining, by a processor having a cache, if data in the cache is to be monitored for cache coherency conflicts in a transactional memory (TM) environment. A processor executes a TM transaction, that includes the following. Executing a memory data access instruction that accesses an operand at an operand memory address. Based on either a prefix instruction associated with the memory data access instruction, or an operand tag associated with the operand of the memory data access instruction, determining whether a cache entry having the operand is to be marked for monitoring for cache coherency conflicts while the processor is executing the transaction. Based on determining that the cache entry is to be marked for monitoring for cache coherency conflicts while the processor is executing the transaction, marking the cache entry for monitoring for conflicts.

Abstract: A Conditional Transaction End (CTEND) instruction is provided that allows a program executing in a nonconstrained transactional execution mode to inspect a storage location that is modified by either another central processing unit or the Input/Output subsystem. Based on the inspected data, transactional execution may be ended or aborted, or the decision to end/abort may be delayed, e.g., until a predefined event occurs. For instance, when the instruction executes, the processor is in a nonconstrained transaction execution mode, and the transaction nesting depth is one at the beginning of the instruction, a second operand of the instruction is inspected, and based on the inspected data, transaction execution may be ended or aborted, or the decision to end/abort may be delayed, e.g., until a predefined event occurs, such as the value of the second operand becomes a prespecified value or a time interval is exceeded.

Abstract: Embodiments relate to selectively blocking branch instruction predictions. An aspect includes a computer system for performing selective branch prediction. The system includes memory and a processor, and the system is configured to perform a method. The method includes detecting a branch-prediction blocking instruction in a stream of instructions and blocking branch prediction of a predetermined number of branch instructions following the branch-prediction blocking instruction based on the detecting the branch-prediction blocking instruction.