// SPDX-License-Identifier: GPL-2.0-or-later
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/* mpihelp-sub.c - MPI helper functions
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* Copyright (C) 1994, 1996 Free Software Foundation, Inc.
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* Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* Note: This code is heavily based on the GNU MP Library.
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* Actually it's the same code with only minor changes in the
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* way the data is stored; this is to support the abstraction
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* of an optional secure memory allocation which may be used
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* to avoid revealing of sensitive data due to paging etc.
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* The GNU MP Library itself is published under the LGPL;
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* however I decided to publish this code under the plain GPL.
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*/
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#include "mpi-internal.h"
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/****************
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* Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
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* There are no restrictions on the relative sizes of
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* the two arguments.
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* Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
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*/
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int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size)
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{
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mpi_size_t i;
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mpi_limb_t op1_word, op2_word;
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for (i = size - 1; i >= 0; i--) {
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op1_word = op1_ptr[i];
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op2_word = op2_ptr[i];
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if (op1_word != op2_word)
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goto diff;
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}
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return 0;
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diff:
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/* This can *not* be simplified to
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* op2_word - op2_word
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* since that expression might give signed overflow. */
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return (op1_word > op2_word) ? 1 : -1;
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}
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