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Multisequencing a Single Instruction Stream Common Register File

IP.com Disclosure Number: IPCOM000103913D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 4 page(s) / 148K

Publishing Venue

IBM

Related People

Ekanadham, K: AUTHOR [+2]

Abstract

MSIS is a uniprocessor organization in which a set of processing elements (PEs) 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.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 34% of the total text.

Multisequencing a Single Instruction Stream Common Register File

      MSIS  is  a  uniprocessor  organization  in  which  a set of
processing elements (PEs) 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  all  PEs  see  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 PEs 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
instructions  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.

      Individual  instructions, while executing, carry an indication
as to which SEGMENT,  DECODER,  and  THREAD  to  which  they belong.

The information concerning the DECODER and THREAD is derived from the
Z-CODE  itself.  The  SEGMENT  index  is assigned   sequentially  at
each  SEGMENT  SWITCH.  Segment switches occur at points in the  code
where  the  Z-SEGMENT terminates or where a Branch Wrong Guess has
been detected.

      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.  Thus, the action of S-LIST and/or D-LIST  entries
within  the  Z-CODE activates  and deacti...