ARM LIMITEDDownload PDFPatent Trials and Appeals BoardMar 17, 20222021001902 (P.T.A.B. Mar. 17, 2022) Copy Citation 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. 15/334,628 10/26/2016 Alexander Alfred HORNUNG JRL-550-2038 6384 73459 7590 03/17/2022 NIXON & VANDERHYE, P.C. 901 NORTH GLEBE ROAD, 11TH FLOOR ARLINGTON, VA 22203 EXAMINER ALLI, KASIM A ART UNIT PAPER NUMBER 2183 NOTIFICATION DATE DELIVERY MODE 03/17/2022 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): PTOMAIL@nixonvan.com pair_nixon@firsttofile.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ________________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ________________ Ex parte ALEXANDER ALFRED HORNUNG and ADRIAN VIOREL POPESCU ________________ Appeal 2021-001902 Application 15/334,628 Technology Center 2100 ________________ Before ROBERT E. NAPPI, JASON J. CHUNG, and BETH Z. SHAW, Administrative Patent Judges. CHUNG, Administrative Patent Judge. DECISION ON APPEAL Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals the Final Rejection of claims 1, 3-5, and 7-17.2 We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. INVENTION The invention relates to branch prediction in data processing. Spec. 1:2-3. Claim 1 is illustrative of the invention and is reproduced below: 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42. According to Appellant, Arm Limited is the real party in interest. Appeal Br. 3. 2 According to the claims filed on February 14, 2020, claims 2 and 6 are cancelled. Appeal 2021-001902 Application 15/334,628 2 1. An apparatus comprising: instruction fetch circuitry to retrieve instructions from storage by reference to addresses at which the instructions are stored; branch target storage to store entries comprising source and target addresses for branch instructions, wherein the branch target storage is capable of storing a confidence value associated with an entry and the branch target storage is responsive to a current address matching a source address in the entry and the confidence value exceeding a confidence threshold to issue a signal to the instruction fetch circuitry to retrieve a predicted next instruction from a target address in the entry; and branch confidence update circuitry to increase the confidence value of the entry in response to receipt of a confirmation of the target address and to decrease the confidence value of the entry in response to receipt of a non-confirmation of the target address, wherein the branch confidence update circuitry is responsive to (a) the confidence value meeting a confidence lock threshold below the confidence threshold and (b) receipt of the non-confirmation of the target address, and wherein subsequent to (a) and (b), the branch confidence update circuitry is configured to lock the entry which prevents issuance of the signal to the instruction fetch circuitry with respect to the locked entry, and wherein a locking mechanism is configured to mark the entry as a locked entry and the branch confidence update circuitry is responsive to the locked entry to cease further modification of the confidence value of the locked entry. Appeal Br. 17-18 (Claims Appendix) (emphasis added). REJECTIONS The Examiner rejects claims 1, 3, 7, and 14-17 under 35 U.S.C. § 103 as being unpatentable over the combination of Bradford (US Pat. No. Appeal 2021-001902 Application 15/334,628 3 7,707,396 B2; issued Apr. 27, 2010) and Park (US Pat. No. 7,434,037 B2; issued Oct. 7, 2008). Final Act. 9-19. The Examiner rejects claims 4 and 5 under 35 U.S.C. § 103 as being unpatentable over the combination of Bradford, Park, and Busaba (US 2014/0201508 A1; published July 17, 2014). Final Act. 19-21. The Examiner rejects claims 8-13 under 35 U.S.C. § 103 as being unpatentable over the combination of Bradford, Park, and Bonanno (US 2003/0212882 A1; published Nov. 13, 2003). Final Act. 21-25. ANALYSIS I. Appellant’s Argument Denoted as “C” in the Appeal Brief The Examiner finds Bradford teaches step 412 that determines when a score has fallen below a predetermined minimum threshold, then removing entries from BTB 150, placing those entries into victim cache 160, and step 432 determines that there is not a match to the branch target address before removing the entries from victim cache 160, which the Examiner maps to the limitation responsive to (a) the confidence value meeting a confidence . . . threshold below the confidence threshold and (b) receipt of the non-confirmation of the target address, and wherein subsequent to (a) and (b), the branch confidence update circuitry is configured to [remove] the entry which prevents issuance of the signal to the instruction fetch circuitry with respect to the [removed] entry recited in claim 1. Ans. 3-6 (Bradford, 6:25-27, 6:41-45, 8:11-21, 8:36- 47); Final Act. 10-11 (citing Bradford, 8:11-21, 8:36-48). Appellant argues the Examiner improperly mixes Figure 4A of Bradford with Figure 4B of Bradford because the portion of Bradford’s Figure 4B relied upon by the Examiner removes entries from victim cache Appeal 2021-001902 Application 15/334,628 4 160 while the portion of Bradford’s Figure 4A relied upon by the Examiner removes entries from BTB 150. Appeal Br. 10-13; Reply Br. 2-4. We disagree with Appellant. Bradford teaches step 412 that determines when the score has fallen below a predetermined minimum threshold (i.e., confidence value meeting a confidence threshold below a confidence threshold), then removing entries from BTB 150, placing those entries into victim cache 160, and step 432 determines that there is not a match to the branch target address (i.e., receipt of the non-confirmation of the target address) before removing (i.e., responsive to (a) and (b), the branch confidence update circuitry removes the entry) the entries from victim cache 160, which teaches the limitation responsive to (a) the confidence value meeting a confidence . . . threshold below the confidence threshold and (b) receipt of the non-confirmation of the target address, and wherein subsequent to (a) and (b), the branch confidence update circuitry is configured to [remove] the entry which prevents issuance of the signal to the instruction fetch circuitry with respect to the [removed] entry recited in claim 1. Ans. 3-6 (Bradford, 6:25-27, 6:41-45, 8:11-21, 8:36- 47); Final Act. 10-11 (citing Bradford, 8:11-21, 8:36-48). Therefore, Appellant does not persuade us of error. II. Appellant’s Argument Denoted as “D” The Examiner finds Bradford teaches removing an entry from victim cache 160. Ans. 3-6 (Bradford, 8:44-47); Final Act. 10-11 (citing Bradford, 8:44-48). In addition, Appellant argues Bradford merely teaches evicting an entry from BTB 150 to victim cache 160 rather than an entry being removed from victim cache. Appeal Br. 13; Reply Br. 4. We disagree with Appeal 2021-001902 Application 15/334,628 5 Appellant. Bradford teaches removing an entry from victim cache 160. Ans. 3-6 (Bradford, 8:44-47); Final Act. 10-11 (citing Bradford, 8:44-48). Therefore, Appellant does not persuade us of error. III. Appellant’s Argument Denoted as “E” The Examiner finds Bradford teaches removing entries and ceases further modification of the score of the removed entry, which the Examiner maps to the limitation “wherein a . . . mechanism is configured to [remove] . . . and the branch confidence update circuitry is responsive to the [removed] entry to cease further modification of the confidence value of the locked entry” recited in claim 1. Ans. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B); Final Act. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B). In addition, the Examiner finds Park teaches an exclusion predictor that inhibits updating information, which the Examiner maps to the limitations “locking” and “mark the entry as a locked entry” recited in claim 1. Ans. 9-10 (citing Park, 4:44-55); Final Act. 11-12 (citing Park, abstract, 4:44-56). Appellant argues Bradford fails to teach marked as removed because if Bradford’s entry is still in the victim cache, then it has not yet been removed even if the victim cache entry will be removed subsequently. Appeal Br. 13; Reply Br. 4-5. We disagree with Appellant. One cannot show nonobviousness “by attacking references individually” where the rejections are based on combinations of references. In re Merck & Co., 800 F.2d 1091, 1097 (Fed. Cir. 1986) (citing In re Keller, 642 F.2d 413, 425 (CCPA 1981)). In this case, the Examiner relies on Bradford to teach removing entries (i.e., a mechanism that removes) that ceases further modification of the score of the removed entry, which teaches Appeal 2021-001902 Application 15/334,628 6 the limitation “wherein a . . . mechanism is configured to [remove] . . . and the branch confidence update circuitry is responsive to the [removed] entry to cease further modification of the confidence value of the locked entry” recited in claim 1. Ans. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B); Final Act. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B). Also, the Examiner relies on Park to teach an exclusion predictor (i.e., mark the entry as a locked entry) that inhibits (i.e., locking) updating information, which teaches the limitations “locking” and “mark the entry as a locked entry” recited in claim 1. Ans. 9-10 (citing Park, 4:44-55); Final Act. 11-12 (citing Park, abstract, 4:44-56). Therefore, Appellant does not persuade us of error. IV. Appellant’s Argument Denoted as “F” The Examiner finds Bradford teaches block 307 depicts determining whether score field 158 of matching entry 152 or 162 exceeds a prediction threshold determinative of whether the accuracy of branch target address prediction contained in the matching entry is high enough to warrant its use and different prediction thresholds can be applied to BTB 150 and victim cache 160. Ans. 11-12 (citing Bradford, 7:14-19); Final Act. 9-11. Appellant argues Bradford fails to teach a confidence lock threshold below the confidence threshold because Bradford does not teach any particular numerical relationship between Bradford’s “predetermined minimum threshold” used in Figure 4A, and Bradford’s “prediction threshold” used in Figure 3. Appeal Br. 14; Reply Br. 6. We disagree with Appellant. Bradford teaches block 307 depicts determining whether score field 158 of matching entry 152 or 162 exceeds a prediction threshold Appeal 2021-001902 Application 15/334,628 7 determinative and this can be applied to BTB 150 and victim cache 160. Ans. 11-12 (citing Bradford, 7:14-19); Final Act. 9-11. Therefore, Appellant does not persuade us of error. V. Appellant’s Argument Denoted as “G” The Examiner finds Bradford teaches removing entries that ceases further modification of the score of the removed entry, which the Examiner maps to the limitation “wherein a . . . mechanism is configured to [remove] . . . and the branch confidence update circuitry is responsive to the [removed] entry to cease further modification of the confidence value of the locked entry” recited in claim 1. Ans. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B); Final Act. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B). In addition, the Examiner finds Park teaches an exclusion predictor that inhibits updating information, which the Examiner maps to the limitations “locking” and “mark the entry as a locked entry” recited in claim 1. Ans. 9-10 (citing Park, 4:44-55); Final Act. 11-12 (citing Park, abstract, 4:44-56). Appellant argues the combination of Bradford and Park fails to teach locking because Bradford lacks locking and Park’s exclusion predictor merely inhibits, but does not have an ongoing effect as a skilled artisan would equate to locking. Appeal Br. 14-15; Reply Br. 6-7. We disagree with Appellant. One cannot show nonobviousness “by attacking references individually” where the rejections are based on combinations of references. In re Merck & Co., 800 F.2d 1091, 1097 (Fed. Cir. 1986) (citing In re Keller, 642 F.2d 413, 425 (CCPA 1981)). In this case, the Examiner relies on Bradford to teach removing entries (i.e., a mechanism that removes) that ceases further modification of the score of the removed entry, which teaches Appeal 2021-001902 Application 15/334,628 8 the limitation “wherein a . . . mechanism is configured to [remove] . . . and the branch confidence update circuitry is responsive to the [removed] entry to cease further modification of the confidence value of the locked entry” recited in claim 1. Ans. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B); Final Act. 9 (citing Bradford, 8:18-21, 8:36-41, Fig. 4B). Also, the Examiner relies on Park to teach an exclusion predictor (i.e., mark the entry as a locked entry) that inhibits (i.e., locking) updating information, which teaches the limitations “locking” and “mark the entry as a locked entry” recited in claim 1. Ans. 9-10 (citing Park, 4:44-55); Final Act. 11-12 (citing Park, abstract, 4:44-56). Regarding Appellant’s argument pertaining to the “ongoing effect” of locking, this is not recited in claim 1. “[A]ppellant’s arguments fail from the outset because . . . they are not based on limitations appearing in the claims.” In re Self, 671 F.2d 1344, 1348 (CCPA 1982). Appellant does not argue claims 3-5, 7-17 separately with particularity. Appeal Br. 8-15. Accordingly, we sustain the Examiner’s rejection of: (1) independent claims 1, 16,3 and 17; and (2) dependent claims 3-5 and 7-15 under 35 U.S.C. § 103. We have only considered those arguments that Appellant actually raised in the Briefs. Arguments Appellant could have made, but chose not to make, in the Briefs have not been considered and are deemed to be waived. See 37 C.F.R. § 41.37(c)(1)(iv). 3 Claim 16 recites “when” and “subsequent to (a) and (b) being detected.” We note that these limitations are conditional, which means the resulting language, in the recited method, typically need not be satisfied to meet such a claim. Ex parte Schulhauser, No. 2013-007847, 2016 WL 6277792 (PTAB Apr. 28, 2016) (precedential). Appeal 2021-001902 Application 15/334,628 9 CONCLUSION 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). See 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED Claim(s) Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 3, 7, 14- 17 103 Bradford, Park 1, 3, 7, 14- 17 4, 5 103 Bradford, Park, Busaba 4, 5 8-13 103 Bradford, Park, Bonanno 8-13 Overall Outcome 1, 3-5, 7- 17 Copy with citationCopy as parenthetical citation