Browse Prior Art Database

Segment Translation Lookaside Entries

IP.com Disclosure Number: IPCOM000043167D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Knight, JW: AUTHOR [+4]

Abstract

A TLB (Translation Lookaside Buffer) is utilized to translate virtual to real addresses. This bypasses a lengthy two-level (segment/page table) lookup scheme. The high-order portion of the address (12 low-order bits show Bx within the page) indicates the virtual page number (VA). The VA can be further broken down to segment index (SX) and a page index (PX). VA = SX.PX. Certain segments are non-pageable and non-swappable. If the page frames are allocated consecutively on a segment size boundary, the SX translation suffices to perform the translation from VA to real page frame addresses since the PX for both the real address and VA are the same. Such entries are then flagged within the TLB, and multiple entries per segment are not required since any/all pages within the segment can be translated.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Segment Translation Lookaside Entries

A TLB (Translation Lookaside Buffer) is utilized to translate virtual to real addresses. This bypasses a lengthy two-level (segment/page table) lookup scheme. The high-order portion of the address (12 low-order bits show Bx within the page) indicates the virtual page number (VA). The VA can be further broken down to segment index (SX) and a page index (PX). VA = SX.PX. Certain segments are non-pageable and non-swappable. If the page frames are allocated consecutively on a segment size boundary, the SX translation suffices to perform the translation from VA to real page frame addresses since the PX for both the real address and VA are the same. Such entries are then flagged within the TLB, and multiple entries per segment are not required since any/all pages within the segment can be translated. A selective purge capability that retains these entries will also improve TLB performance. Selective purging can be used with common segments in existing systems.

1