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// SPDX-License-Identifier: GPL-2.0-or-later
/* mpihelp-sub.c - MPI helper functions
* Copyright (C) 1994, 1996 Free Software Foundation, Inc.
* Copyright (C) 1998, 1999, 2000, 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"
/****************
* Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
* There are no restrictions on the relative sizes of
* the two arguments.
* Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
*/
int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size)
{
mpi_size_t i;
mpi_limb_t op1_word, op2_word;
for (i = size - 1; i >= 0; i--) {
op1_word = op1_ptr[i];
op2_word = op2_ptr[i];
if (op1_word != op2_word)
goto diff;
}
return 0;
diff:
/* This can *not* be simplified to
* op2_word - op2_word
* since that expression might give signed overflow. */
return (op1_word > op2_word) ? 1 : -1;
}
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