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On-Demand Code Replication in a Firmly Coupled Microprocessor Environment

IP.com Disclosure Number: IPCOM000116800D
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Petrillo, RA: AUTHOR

Abstract

A method of replicating nucleus code on demand in a Firmly Coupled Microprocessor Environment (FCMP) is disclosed. The master node of a firmly coupled machine is loaded with the nucleus and the executable routines are copied to the slave nodes when they are needed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 82% of the total text.

On-Demand Code Replication in a Firmly Coupled Microprocessor Environment

      A method of replicating nucleus code on demand in a Firmly
Coupled Microprocessor Environment (FCMP) is disclosed.  The master
node of a firmly coupled machine is loaded with the nucleus and the
executable routines are copied to the slave nodes when they are
needed.

      When a firmly coupled microprocessor system is loaded at power
on time, the nucleus code is loaded into the master node.  The
storage of the slave nodes is initialized to zero by the memory test
routine.  The interrupt vectors of the slave nodes are updated to
point to the interrupt handlers in the master node.  This will allow
a slave node to handle interrupts.

      The program interrupt handler is modified to first check if the
interrupt was caused by the execution of an invalid operation, if so
it needs to check if the opcode for the operation was zero and if the
address of the operation is in the nucleus range of the slave node.
If all of these conditions are true, then the program interrupt
handler copies the executable routine from the master node to the
slave node.  After the routine has been copied, the program interrupt
handler will execute a Return From Interrupt (RFI) instruction which
will attempt to re-execute the instruction which incurred the
interrupt.  This time the code is in the slave node's storage and a
trap will not occur.

      By modifying the program interrupt handler as above,...