International Business Machines Corporation

Alan I Alpert

Michael Gerard Mall

Paul Gregory Greenstein

John Ted Rodell

Carl Edward Clark

Jeffrey Alan Frey

Casper A Scalzi

Bhaskar Sinha

Ramanathan Raghavan

Richard J Schmalz, Deceased

Michel Henri Hack

Ramanathan Raghayan

A Test Operation-Code (TSTOP) instruction pre-verifies the validity of a target instruction op-code prior to execution of the target instruction. The pre-verification function, contained within CPU execution unit microcode, sets a return value in a program status word to indicate one of four conditions:

Apparatus and method for pre-verifying a computer instruction set to

Method and apparatus for verifying a target instruction before execution

In one aspect, a software development technique is capable of efficiently organizing for execution a conditional code segment having multiple associated conditional paths. The development technique employs in association with each path of the code segment, a probability compiler directive which dictates to the compiler a probability for satisfying a conditional test of the associated path. In another aspect, a system/process is capable of optimizing organization of assembled program code for a code's particular execution environment. This optimization approach tunes assembled code organization for each specific execution environment, employing run-time based statistical data collected during performance execution of the assembled code. The execution environment, consisting of hardware, software, and other factors such as workload, input data, etc., can also be collected and employed by an optimizer unit to best reorganize the assembled program code for a current execution environment.

Optimizing assembled code for execution using execution statistics

A method and system for providing a PROGRAM CALL to a dispatchable unit's base space is described herein. A program call to a dispatchable unit's (PC to DU) base space bit is added to each entry-table entry in order to determine whether a PROGRAM CALL to a base space is to be made. Should the bit indicate that a PROGRAM CALL to a dispatchable unit's base space is to be made, then in one embodiment, the base address space number-second-table entry origin (BASTEO) and base address space number (BASN) stored in the dispatchable unit control table (DUCT) are used in identifying the base space and accessing associated control information for the identified base space. In another embodiment, the BASN stored in the DUCT is used in ASN translation to identify the base space and access the associated control information for the base space.

Method and system for providing a program call to a dispatchable unit's

Provides a dynamic execution link between an analyzer program and each hook instruction in a program. Special types of hook instructions are provided for use in a hooked program. The link causes the analyzer program to execute as part of a continuous uninterrupted execution for each hook instruction. The link uses hardware and/or internal code to access a hook control area which provides linkage information needed to invoke the execution of the analyzer program upon completion of the hook instruction and to continue the execution of the hooked program following the completion of the analyzer program. The linkage information includes the entry location into the analyzer program, and also locates the first hook work area (HWA) of a sequence of HWAs, from which an HWA is assigned to each current hook instruction. The assigned HWA stores a return point location in the hooked program at an instruction following the current hook instruction. One or more hooked programs may concurrently use the same analyzer program. As soon as execution by the analyzer program ends for a hook instruction, its assigned HWA is released for use by another hook instruction.

Dynamic program analyzer facility

Program construct and methods/systems for optimizing assembled code for

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Hopewell Junction, NY, United States of America

Alan I Alpert