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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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