International Business Machines Corporation

Marcel Mitran

Timothy John Slegel

Christian Jacobi

Dan F Greiner

Charles W Gainey, Jr

Reid T Copeland

Donald W Schmidt

Chung-Lung K Shum

Kevin Alexander Stoodley

Ali Ijaz Sheikh

Eric M Schwarz

Steven R Carlough

Theodore Joseph Bohizic

Alexander A Vasilevskiy

Mark S Farrell

Brian L Smith

Anthony Saporito

Maged M Michael

Martin Ohmacht

Vijay Sundaresan

Kai-Ting Amy Wang

Volodymyr Paprotski

Timothy Slegel

Joran S C Siu

Brian Robert Prasky

Damian Leo Osisek

Charles Franklin Webb

James J Bonanno

Andrew Russell Low

Jose Nelson Amaral

Kishor V Patil

Adam Paul Jocksch

Joran Siu

Reid Copeland

Dan Greiner

Jr Gainey Charles

Steven Carlough

Chung-Lung Kevin Shum

Charles W Gainey

Eric Mark Schwarz

William J Rooney

K Paul Muller

David S Wolpert

Mark Graham Stoodley

Moriyoshi Ohara

Graeme Johnson

Karl Michael Taylor

Patrick R Doyle

Derek Bruce Inglis

Marius Pirvu

Daryl James Maier

Alexander Steven Ross

Levon Sassoon Stepanian

Gavin Rolleston

Visda Vokhshoori

Alexander Vaseilevskiy

Chung-Ling K Shum

Francis Bogsanyl

Ivan Sham

Ali L Sheikh

Brian Leonard Smith

Charles W Gainey Jr

Kevin A Stoodley

A computer-implemented method includes the following operations. A transactional lock elision transaction including a critical section is executed. The critical section is processed. After the processing of the critical section and prior to a commit point in the transactional lock elision transaction, a status of a lock is checked. Responsive to a determination that a status of the lock is free, a result of the transactional lock elision transaction is committed.

Transactional lock elision with delayed lock checking

A TRANSACTION BEGIN instruction and a TRANSACTION END instruction are provided. The TRANSACTION BEGIN instruction causes either a constrained or nonconstrained transaction to be initiated, depending on a field of the instruction. The TRANSACTION END instruction ends the transaction started by the TRANSACTION BEGIN instruction.

Transaction begin/end instructions

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.

Identifying processor attributes based on detecting a guarded storage event

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.

Conditional transaction end instruction

A conditional instruction end facility is provided that allows completion of an instruction to be delayed. In executing the machine instruction, an operand is obtained, and a determination is made as to whether the operand has a predetermined relationship with respect to a value. Based on determining that the operand does not have the predetermined relationship with respect to the value, the obtaining and the determining are repeated. Based on determining that the operand has the predetermined relationship with respect to the value, execution of the instruction is completed. The obtaining the operand, the determining whether the operand has the predetermined relationship, the based on determining that the operand does not have the predetermined relationship with respect to the value, repeating the obtaining and the determining, and the based on determining that the operand has the predetermined relationship with respect to the value, completing execution of the instruction are performed as part of a single instruction having one operation code.

Conditional instruction end operation

A delay facility is provided in which program execution may be delayed until a predefined event occurs, such as a comparison of memory locations results in a true condition, a timeout is reached, an interruption is made pending or another condition exists. The delay facility includes one or more compare and delay machine instructions used to delay execution. The one or more compare and delay instructions may include a 32-bit compare and delay (CAD) instruction and a 64-bit compare and delay (CADG) instruction.

Compare and delay instructions

Loading and storing controls regulating the operation of a guarded storage facility

Machine instructions, referred to herein as a long Convert from Zoned instruction (CDZT) and extended Convert from Zoned instruction (CXZT), are provided that read EBCDIC or ASCII data from memory, convert it to the appropriate decimal floating point format, and write it to a target floating point register or floating point register pair. Further, machine instructions, referred to herein as a long Convert to Zoned instruction (CZDT) and extended Convert to Zoned instruction (CZXT), are provided that convert a decimal floating point (DFP) operand in a source floating point register or floating point register pair to EBCDIC or ASCII data and store it to a target memory location.

Convert to zoned format from decimal floating point format

Load logical and shift guarded instruction

Program exception conditions cause a transaction to abort and typically result in an interruption in which the operating system obtains control. A program interruption filtering control is provided to selectively present the interrupt. That is, the interrupt from the program exception condition may or may not be presented depending at least on the program interruption filtering control and a transaction class associated with the program exception condition. The program interruption filtering control is provided by a TRANSACTION BEGIN instruction.

Program interruption filtering in transactional execution

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Markham, Canada

Marcel Mitran