Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Address Space Indexing Using an Address Space Index Stack

IP.com Disclosure Number: IPCOM000061433D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Bourke, D: AUTHOR [+8]

Abstract

For protection reasons, it is desirable to move from using real keys to using indexes for address space keys on an IBM Series/1 processor having an extended address feature. This is done using an Address Space Index Stack (ASIS). Reference is made to the articles on pages 968 and 974 of this issue that are of interest. The following expressions are sometimes used in the various articles including the present article. Reference is made to the drawings of the aforementioned articles for the elements listed. Only those elements involved in the extended addressing operation that are especially pertinent to the present discussion are illustrated in the drawing.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Address Space Indexing Using an Address Space Index Stack

For protection reasons, it is desirable to move from using real keys to using indexes for address space keys on an IBM Series/1 processor having an extended address feature. This is done using an Address Space Index Stack (ASIS). Reference is made to the articles on pages 968 and 974 of this issue that are of interest. The following expressions are sometimes used in the various articles including the present article. Reference is made to the drawings of the aforementioned articles for the elements listed. Only those elements involved in the extended addressing operation that are especially pertinent to the present discussion are illustrated in the drawing. ASIR Address Space Index Register ASIS Address Space Index Stack EAKR Extended Address Key Register EGPR Extended General Purpose Register ELSR Extended Level Status Register GPR General Purpose Register GRAM General Register Active Mask GRI General Register Index ISI Instruction Space Index LSR Level Status Register OP1I Operand One Index (Controls Access of Date from Storage) OP2I Operand Two Index (Controls Access of Data into Storage) In these articles, an Extended Addressing feature is described that may be used with the IBM Series/1 processor, as an example. This feature (EAS/1) provides the capability for application programs to address more than 64 KB of logical storage. Also, the EAS/1 architecture allows operating systems to efficiently support more than 512 KB of physical storage. The general approach is to provide a minimum of 24 bits of addressing (16 MB linear space...