Browse Prior Art Database

Early Synchronization Pulse On Load Multiple And Store Multiple

IP.com Disclosure Number: IPCOM000100570D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Kahle, JA: AUTHOR [+2]

Abstract

This article describes a way to look ahead on translation during load multiple and store multiple instructions. In a system with a branch processing unit that must wait for interruptible instructions to complete, this invention helps increase system performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Early Synchronization Pulse On Load Multiple And Store Multiple

       This article describes a way to look ahead on translation
during load multiple and store multiple instructions.  In a system
with a branch processing unit that must wait for interruptible
instructions to complete, this invention helps increase system
performance.

      In a RISC system, a sync pulse is sent from the fixed point
unit (FXU) to the instruction cache unit (ICU) when all the
translation has completed for a load or store operation.  Separate
translation occurs for each word that is loaded or stored.  This
implies that the sync pulse cannot be sent to the ICU until the end
of a load multiple or store multiple.  This article describes a way
to translate the first storage access, then predict if the remaining
storage accesses will be successful.  With a correct prediction
mechanism, the sync pulse can be sent after the first translation.

      Translation errors may occur during a memory storage reference
(i.e., loads or stores).  However, they may only occur at certain
memory boundary conditions called pages. If a load (or store) access
is more than one page, then it is possible for a translation error to
occur.

      Load/store multiple type instructions in a RISC system can
access from 1 to 33 consecutive words in memory.  If this range of
words lies across two pages, then a translation error is possible.
Prediction of a possible translation error would allow early s...