[openssl/openssl] eae701: Revert "Revert "bn: Add fixed length (n=6), unroll...

[openssl-machine]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: eae70100fadbc94f18ba7a729bf065cb524a9fc9
      https://github.com/openssl/openssl/commit/eae70100fadbc94f18ba7a729bf065cb524a9fc9
  Author: Rohan McLure <rohanmclure at linux.ibm.com>
  Date:   2022-08-17 (Wed, 17 Aug 2022)

  Changed paths:
    M crypto/bn/asm/ppc64-mont-fixed.pl
    M crypto/bn/bn_ppc.c
    M crypto/bn/build.info

  Log Message:
  -----------
  Revert "Revert "bn: Add fixed length (n=6), unrolled PPC Montgomery Multiplication""

This reverts commit 712d9cc90e355b2c98a959d4e9398610d2269c9e.

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18883)


  Commit: 2f1112b22a826dc8854b41b60a422c987f8ddafb
      https://github.com/openssl/openssl/commit/2f1112b22a826dc8854b41b60a422c987f8ddafb
  Author: Rohan McLure <rohanmclure at linux.ibm.com>
  Date:   2022-08-17 (Wed, 17 Aug 2022)

  Changed paths:
    M crypto/bn/asm/ppc64-mont-fixed.pl

  Log Message:
  -----------
  Fix unrolled montgomery multiplication for POWER9

In the reference C implementation in bn_asm.c, tp[num + 1] contains the
carry bit for accumulations into tp[num]. tp[num + 1] is only ever
assigned, never itself incremented.

Reviewed-by: Hugo Landau <hlandau at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18883)


Compare: https://github.com/openssl/openssl/compare/f86845425756...2f1112b22a82