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Browse Prior Art Database

Dual Task Hardware Partitioned Local Working Store

IP.com Disclosure Number: IPCOM000118421D
Original Publication Date: 1997-Feb-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 75K

Publishing Venue

IBM

Related People

Errickson, RK: AUTHOR [+4]

Abstract

This technique provides for a hardware partitioned Local Working Store (LWS) design that allows for two independent tasks, running in a Reduced Instruction Set Computer, to own their own independent private address space and also share a common address space. The design also allows for the size of the areas to be programmable by the licensed internal code.

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This is the abbreviated version, containing approximately 52% of the total text.

Dual Task Hardware Partitioned Local Working Store

      This technique provides for a hardware partitioned Local
Working Store (LWS) design that allows for two independent tasks,
running in a Reduced Instruction Set Computer, to own their own
independent private address space and also share a common address
space.  The design also allows for the size of the areas to be
programmable by the  licensed internal code.

      Disclosed is a design for partitioning a Local Working Store
array, by hardware, into three separate areas: a private area for
each task, in this case two, and a shared common area.  This allows
for two independent tasks to time share a Local Working Store array
without completely duplicating the entire array, one copy for each
task.  Allowing for a common area, shared by both tasks, in the
design relieves the need to have duplicated information store in the
LWS array  resulting in less storage size needed.  The partitioning
of the LWS array  is solely managed by hardware, but the
initialization of the size of each partition is programmable by the
licensed internal microcode.

      The hardware implemented to accomplish this design consists of
a two byte address register and two independent address adders.  The
address register, TSAR in Fig. 1, holds two 1-byte offset addresses,
one associated with each task.  Fig. 1 illustrates the partitioning
of the Local Working Store array and how the offset addresses in TSAR
are used to point to the start of each of the private areas.  The
common area starts at physical address '0'X.

      As shown i...