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Forced Enablement of Program Event Recording for a Guest, Including a BC-Mode Guest

IP.com Disclosure Number: IPCOM000117262D
Original Publication Date: 1996-Jan-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Conklin, CR: AUTHOR [+3]

Abstract

A bit is placed in the state description used by the ESA/390* Start Interpretive Execution (SIE) instruction and is ORed with the Program Event Recording (PER) mask in a guest Program Status Word (PSW) to force enablement of PER for the guest. The bit also enables PER for a System/370* Basic Control mode (BC-mode) guest, for which PER was previously not available.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Forced Enablement of Program Event Recording for a Guest, Including
a BC-Mode Guest

      A bit is placed in the state description used by the ESA/390*
Start Interpretive Execution (SIE) instruction and is ORed with the
Program Event Recording (PER) mask in a guest Program Status Word
(PSW) to force enablement of PER for the guest.  The bit also enables
PER for a System/370* Basic Control mode (BC-mode) guest, for which
PER was previously not available.

      The ESA/390 Start Interpretive Execution (SIE) instruction
causes execution of a virtual machine called a guest.  The program
issuing SIE is called the host.  SIE uses an operand, called a state
description, that contains guest register contents, including the
guest program status word (PSW), at both the beginning and the end of
the guest execution.  The end of guest execution is called
interception of the guest and causes the end of the SIE execution.
SIE is executed again to resume guest execution.  A guest can be an
ESA/390-mode or System/370-mode guest.

      Program Event Recording (PER) provides program interruptions on
certain types of events.  PER is enabled for a guest by a PER mask
(bit) in either an ESA/390 guest PSW or a System/370 Extended Control
mode (EC-mode) guest PSW.  The System/370 Basic Control mode
(BC-mode) PSW does not have a PER mask, and PER is not available for
a BC-mode guest.  Guest PER may be enabled by the guest for
debugging, or it may  be enabled by the host for tracing activities
of the guest.

      Pri...