Intel Corporation

Patent Trials and Appeals Board

Sep 2, 2021

2020004488 (P.T.A.B. Sep. 2, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/353,549 11/16/2016 Mohammad Abdallah P111987C4 8079
131413 7590 09/02/2021
NDWE LLP/Intel
99 Almaden Boulevard, Suite 575
San Jose, CA 95113
EXAMINER
LINDLOF, JOHN M
ART UNIT PAPER NUMBER
2183
NOTIFICATION DATE DELIVERY MODE
09/02/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
eofficeaction@appcoll.com
ndwe_docketing@cardinal-ip.com
patent@ndwe.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte MOHAMMAD ABDALLAH

Appeal 2020-004488
Application 15/353,549
Technology Center 2100
____________

Before LARRY J. HUME, JUSTIN BUSCH, and
NORMAN H. BEAMER, Administrative Patent Judges.

BEAMER, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 appeals under 35 U.S.C. § 134(a) from the Examiner’s
final rejection of claims 1, 2, 5, 7–9, 14–16, 19, and 20. Claims 3, 4, 6, 10–
13, 17, 18, and 21 are cancelled. We have jurisdiction over the pending
rejected claims under 35 U.S.C. § 6(b).
We AFFIRM.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. Appellant identifies the real party in interest as Intel
Corporation. (Appeal Br. 2.)
Appeal 2020-004488
Application 15/353,549

2
THE INVENTION
Appellant’s disclosed and claimed invention is directed to supporting
architecture speculation in an out of order processor. (Abstr.)
Independent claim 1, reproduced below, is illustrative of the subject
matter on appeal:
1. A method for supporting architecture speculation in an out
of order processor, the method comprising:
fetching two threads into the processor, wherein a first
thread executes in a speculative state and a second
thread executes in a non-speculative state; and
enabling a speculative scope for an execution of the first
thread and a non-speculative scope for an
execution of the second thread in an architecture of
the processor,
wherein the speculative scope and the non-speculative
scope can both be fetched into the architecture and
be present concurrently,
wherein in a non-speculative mode, register reads are
from committed registers, register
writes are to committed registers, and memory writes are
written to memory,
wherein in a speculative mode, register writes are written
to a speculative scratch shadow
register, register reads are from a latest write, and
memory writes to a retirement memory buffer, and
wherein code in the speculative mode can be rolled back
if an exception occurs where a state of the
speculative scratch shadow register is rolled back
to a state of the committed registers.
(Appeal Br. 12 (Claims App.).)

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REJECTIONS
The Examiner rejected claims 1, 2, 5, 7–9, 14–16, and 19 under
35 U.S.C. § 103(a) (pre-AIA) as being unpatentable over Chaudhry et al.
(US 2004/0133769 A1, pub. July 8, 2004) and Cain, et al. (US
2011/0238962 A1, pub. Sept. 29, 2011). (Final Act. 2–4.)
The Examiner rejected claim 20 under 35 U.S.C. § 103(a) (pre-AIA),
as being unpatentable over Chaudhry, Cain, and Mallick et al. (US
5,961,639, iss. Oct. 5, 1999). (Final Act. 4–5.)
ISSUES ON APPEAL
Appellant’s arguments present the following dispositive issues2:
Issue One: Whether the Examiner erred in finding that the
combination of Chaudhry and Cain taught or suggested the independent
claim 1 requirement, “wherein code in the speculative mode can be rolled
back if an exception occurs where a state of the speculative scratch shadow
register is rolled back to a state of the committed registers,” and the
commensurate requirements of independent claims 7 and 14. (Appeal
Br. 5–7.)
Issue Two: Whether the Examiner erred in finding that the
combination of Chaudhry and Cain taught or suggested the claim 2
requirement, “wherein the speculative scope sets its respective mode
differently from the non-speculative scope.” (Appeal Br. 8.)

2 Rather than reiterate the arguments of Appellant and the positions of the
Examiner, we refer to the Appeal Brief (filed Oct. 8, 2019); the Final Office
Action (mailed May 10, 2019); and the Examiner’s Answer (mailed Jan. 27,
2020) for the respective details.
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ANALYSIS
We have reviewed the Examiner’s rejections in light of Appellant’s
arguments that the Examiner has erred. We disagree with Appellant’s
arguments, and adopt as our own, (1) the findings and reasons set forth by
the Examiner in the Action from which this appeal is taken (Final Act. 2–5);
and (2) the reasons set forth by the Examiner in the Examiner’s Answer in
response to Appellant’s Appeal Brief (Ans. 3–5), and concur with the
conclusions reached by the Examiner.
Issue One
The Examiner concedes that Chaudhry alone does not explicitly teach
the claim limitation at issue. (Final Act. 3, 4.) However, the Examiner finds
that Cain in combination with Chaudhry does so, relying on the disclosure in
Cain of an operation for handling an end of a speculative mode of execution
in which, “[w]hen a speculative execution has to be aborted or ends
unsuccessfully, a roll-back operation is performed such that the state of the
registers is returned to a state prior to entry into the speculative execution
mode,” including that “all valid entries in the recovery renaming table are
written into the register rename table.” (Final Act. 3, 4; Cain Fig. 5, ¶ 44.)
The Examiner further finds:
At the time of the invention it would have been obvious to one
of ordinary skill in the art to combine the teachings of
Chaudhry and Cain such that code in the speculative mode can
be rolled back if an exception occurs where a state of the
speculative scratch shadow register is rolled back to a state of
the committed registers. This would have provided an
advantage of correcting for possible errors to ensure proper
execution.
(Final Act. 3.)
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Appellant argues that the Examiner erred because the portions of Cain
on which the Examiner relies “describe the use of a registry renaming table
and a recovery renaming table in connection with a speculative mode of
execution,” which relate to mapping logical registers to physical registers.
(Appeal Br. 6.) Thus, Appellant argues:
These data structures are not equivalent to committed registers
and shadow register as recited in claim 1, because they do not
serve to handle register reads and writes in the respective modes
of operation as expressly recited in claim 1. Rather, these data
structures of Cain provide logical to physical mappings to
enable the location of data being utilized during speculative
execution. The roll-back operation described in Cain operates
by rolling back mappings rather than rolling back the values of
registers, as recited in claim 1. . . .
(Appeal Br. 6–7.) Appellant further argues that the combination of
Chaudhry and Cain is improper, because “rolling back speculative execution
based on reverting of logical to physical register mappings . . . would change
the operating principle of Chaudhry.” (Appeal Br. 7.)
In response, the Examiner observes that the claims “only require[] the
capability of rolling back register state,” and that “one of ordinary skill in
the art certainly would have recognized at least the capability to roll back
code or a register state in view of the combination of references.” (Ans. 3.)
The Examiner also emphasizes that Cain explicitly discloses that “a roll-
back operation is performed such that the state of the registers is returned to
a state prior to entry into the speculative execution mode.” (Id.; Cain ¶ 44.)
In addition, the Examiner finds:
[T]hat exemplary claim 1 does not limit the scope of the
claimed “state” to differentiate from a register mapping state.
Claim 1 does not provide any specificity regarding what the
claimed “state” is that is rolled back. The scope of a register
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“state” includes a mapping state. Even if the only rolled back
state of the registers in Cain is a mapping state, this would still
meet the claim.
(Ans. 4.) The Examiner further finds that:
[T]he ability to roll back to previous register states would not
change Chaudhry’s principle of operation of processing
instructions. It would simply require the storage and tracking
of checkpoints for restoring a state of the processor.
(Id.)
Appellant does not rebut these findings, and we are not persuaded that
they are in error. Accordingly, we sustain the Examiner’s rejection of
independent claims 1, 7, and 14 over the combination of Chaudhry and Cain.
We also sustain the Examiner’s rejection of claims 5, 8, 9, 15, 16, and 19
over the combination of Chaudhry and Cain, and of claim 20 over the
combination of Chaudhry, Cain, and Mallick, which claims are not argued
separately with particularity. (Appeal Br. 8–10.)
Issue Two
Claim 2 depends from claim 1, and adds the requirement “wherein the
speculative scope sets its respective mode differently from the non-
speculative scope.” (Appeal Br. 12 (Claims App.).) The Examiner finds
that Chaudhry teaches this requirement. (Final Act. 4; Chaudhry, Fig. 3,
¶¶ 50–58.) Appellant argues that the Examiner:
does not set forth how the recited “mode” is set differently for
the speculative and non-speculative scopes. The use of the
shadow register file does not relate explicitly to the setting of
the mode and the Patent Office has failed to articulate how the
use of the shadow register file or any other aspect of the cited
sections of Chaudhry either explicitly or implicitly disclose the
different setting of the mode by the two scopes.
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(Appeal Br. 8.) The Examiner responds:
The claim does not limit the scope of the claimed “mode.” The
claim merely requires that there is some difference in the mode
of the speculative scope as opposed to the non-speculative
scope. Chaudhry describes such a difference of using a shadow
register file differently during a speculative scope as opposed to
an architectural register file during a non-speculative scope (see
e.g.[,] para. [0050-8]).
(Ans. 5.) Appellant does not rebut these findings, and we are not persuaded
that they are in error. Accordingly, we sustain the Examiner’s rejection of
claim 2 over the combination of Chaudhry and Cain.
DECISION SUMMARY
In summary:
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1, 2, 5, 7–
9, 14–16,
19
103 Chaudhry, Cain 1, 2, 5, 7–
9, 14–16,
19

20 103 Chaudhry, Cain,
Mallick
20
Overall
Outcome
1, 2, 5, 7–
9, 14–16,
19, 20

TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED