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Multisequencing a Single Instruction Stream Meta High-End Machine Operations of the Instruction Processing Unit

IP.com Disclosure Number: IPCOM000104418D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 200K

Publishing Venue

IBM

Related People

Ekanadham, K: AUTHOR [+3]

Abstract

MSIS is a uniprocessor organization in which a set of processing elements (PE) working in concert execute Segments of the instruction stream. The Segments are either P-Segments, normal uniprocessor instruction stream portions, that are processed in the E-MODE of MSIS and produce Z-Segments, or the Z-Segments that are processed in Z-MODE by MSIS. The main difference between E-MODE and Z-MODE is that during E-MODE each PE sees all instructions in the Segment and executes the ones that are assigned to it, but during Z-MODE, a PE only sees the instructions assigned to it.

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This is the abbreviated version, containing approximately 28% of the total text.

Multisequencing a Single Instruction Stream Meta High-End Machine Operations of the Instruction Processing Unit

      MSIS  is  a  uniprocessor  organization  in  which  a set of
processing elements (PE) working in concert execute Segments of  the
instruction  stream.  The   Segments   are   either P-Segments,
normal uniprocessor instruction stream portions, that  are  processed
in  the  E-MODE  of  MSIS  and produce Z-Segments, or the Z-Segments
that are processed  in  Z-MODE by  MSIS.  The  main difference
between E-MODE and Z-MODE is that during E-MODE each PE  sees  all
instructions  in  the Segment  and  executes the ones that are
assigned to it, but during Z-MODE, a PE only sees the  instructions
assigned  to it.

      As a PE sees all instructions in E-MODE, each PE can create the
Z-CODE it will require to re-execute the  Segment as a Z-Segment, the
Z-CODE being stored in the Z-CACHE, and associated with instructions
in the Z-CODE are  S-LISTS  and D-LISTS  as  appropriate.  An S-LIST
instructs the PE, in the Z-MODE, that one or more  of  the  source
registers  in  an instruction  assigned  to  it  is set by another
instruction that is executed on another PE, an  S-LIST  is  a
receiving obligation.  The D-LIST instructs the PE in the Z-MODE as
to the names of PE's that require the values of the register(s) that
are being set by an instruction that is assigned to it.  A D-LIST
entry is a sending obligation.

      The set of instructions assigned to a single PE can be further
delineated as THREADS.  A THREAD is a sequence of instruction in the
original conceptual order and a Thread is associated with a register
file which is either real or virtual.  There are no sending or
receiving obligations between  instructions  within a THREAD and the
THREAD is the smallest unit of aggregation of instructions from a
SEGMENT.

      MSIS HEM is a High-End Machine design that uses multiple
decoders within a single processor in the place of separate processor
elements (PEs).  A single  Instruction  Processing Unit  (IPU)
executes  all  instructions  in MSIS HEM albeit through  a
multiplicity  of  registers   files   that   are associated  with
the THREADS.   MSIS META HEM is a Multiple Execution Thread
Architecture  that  separates  the  THREADS from  the next higher
aggregate of instructions the DECODER.  Thus the action of S-LIST
and/or D-LIST entries  within  the Z-CODE  activates  and deactivates
the THREADS and alternate THREADS are decoded.

      At the conclusion of a Z-SEGMENT or at the point of a Branch
Wrong   Guess,  the  register  state  of  the  processor  is
distributed among the register  files  that  constitute  the results
of THREAD processing.  To determine the machine state a  ZZT  is
employed.  The ZZT is a two dimensional structure which is accessed
by  both  architected  register  name  and level ...