diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:29:51 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:29:51 +0000 |
commit | 6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e (patch) | |
tree | 32451fa3cdd9321fb2591fada9891b2cb70a9cd1 /grub-core/lib/libgcrypt-grub/mpi/generic/mpih-rshift.c | |
parent | Initial commit. (diff) | |
download | grub2-6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e.tar.xz grub2-6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e.zip |
Adding upstream version 2.06.upstream/2.06upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'grub-core/lib/libgcrypt-grub/mpi/generic/mpih-rshift.c')
-rw-r--r-- | grub-core/lib/libgcrypt-grub/mpi/generic/mpih-rshift.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/grub-core/lib/libgcrypt-grub/mpi/generic/mpih-rshift.c b/grub-core/lib/libgcrypt-grub/mpi/generic/mpih-rshift.c new file mode 100644 index 0000000..e40794f --- /dev/null +++ b/grub-core/lib/libgcrypt-grub/mpi/generic/mpih-rshift.c @@ -0,0 +1,67 @@ +/* mpih-rshift.c - MPI helper functions + * Copyright (C) 1994, 1996, 1998, 1999, + * 2000, 2001, 2002 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + * + * Note: This code is heavily based on the GNU MP Library. + * Actually it's the same code with only minor changes in the + * way the data is stored; this is to support the abstraction + * of an optional secure memory allocation which may be used + * to avoid revealing of sensitive data due to paging etc. + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include "mpi-internal.h" + + +/* Shift U (pointed to by UP and USIZE limbs long) CNT bits to the right + * and store the USIZE least significant limbs of the result at WP. + * The bits shifted out to the right are returned. + * + * Argument constraints: + * 1. 0 < CNT < BITS_PER_MP_LIMB + * 2. If the result is to be written over the input, WP must be <= UP. + */ + +mpi_limb_t +_gcry_mpih_rshift( mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize, unsigned cnt) +{ + mpi_limb_t high_limb, low_limb; + unsigned sh_1, sh_2; + mpi_size_t i; + mpi_limb_t retval; + + sh_1 = cnt; + wp -= 1; + sh_2 = BITS_PER_MPI_LIMB - sh_1; + high_limb = up[0]; + retval = high_limb << sh_2; + low_limb = high_limb; + for (i=1; i < usize; i++) + { + high_limb = up[i]; + wp[i] = (low_limb >> sh_1) | (high_limb << sh_2); + low_limb = high_limb; + } + wp[i] = low_limb >> sh_1; + + return retval; +} + |