Browse Prior Art Database

Processor Stop Acknowledge to Facilitate Transfer of Control Of Multi-Use Signals

IP.com Disclosure Number: IPCOM000099764D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 85K

Publishing Venue

IBM

Related People

Fuhs, RE: AUTHOR [+4]

Abstract

Described is a means by which any number of processors report information regarding stopping point to a common interface chip over a common bus. The chip reports to the processor that it has reached a point where it can stop processing.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 59% of the total text.

Processor Stop Acknowledge to Facilitate Transfer of Control Of Multi-Use Signals

       Described is a means by which any number of processors
report information regarding stopping point to a common interface
chip over a common bus.  The chip reports to the processor that it
has reached a point where it can stop processing.

      In a computer system using closely coupled multiple central
processing units, processors communicate to an interface chip over a
common bus. (Fig. 1.)  During normal run time, each processor drives
the common bus with data destined for the interface chip if it was
selected the previous cycle.  The selection process is implemented
such that each connected processor is given control in a circular
fashion (Fig. 2) through an individual processor select line during
run mode.  If the processor has no data to drive over the bus, it
then drives a NOP (No Operation) code.

      For service and diagnostic purposes it is necessary to stop the
multiple processor's execution of control words. This is done by the
interface chip indicating to the processors that control word
execution stops when the current control word is complete.  Then the
processors enter a diagnostic mode where control lines from the
interface chip to the processors are driven by an external test
controller to perform the desired service functions.  All processors
may not stop at the same time, and the interface chip must know that
all processors have stopped before an...