Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
51 lines
1.5 KiB
C
51 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* mpihelp-lshift.c - MPI helper functions
|
|
* Copyright (C) 1994, 1996, 1998, 2001 Free Software Foundation, Inc.
|
|
*
|
|
* This file is part of GnuPG.
|
|
*
|
|
* 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.
|
|
* The GNU MP Library itself is published under the LGPL;
|
|
* however I decided to publish this code under the plain GPL.
|
|
*/
|
|
|
|
#include "mpi-internal.h"
|
|
|
|
/* Shift U (pointed to by UP and USIZE digits long) CNT bits to the left
|
|
* and store the USIZE least significant digits of the result at WP.
|
|
* Return the bits shifted out from the most significant digit.
|
|
*
|
|
* 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
|
|
mpihelp_lshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize, unsigned int 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;
|
|
i = usize - 1;
|
|
low_limb = up[i];
|
|
retval = low_limb >> sh_2;
|
|
high_limb = low_limb;
|
|
while (--i >= 0) {
|
|
low_limb = up[i];
|
|
wp[i] = (high_limb << sh_1) | (low_limb >> sh_2);
|
|
high_limb = low_limb;
|
|
}
|
|
wp[i] = high_limb << sh_1;
|
|
|
|
return retval;
|
|
}
|