annotate bn_mp_to_unsigned_bin.c @ 163:8e94663164c6 libtommath LTM_DB_0.44

make pointers volatile so that memory zeroing won't get optimised away
author Matt Johnston <matt@ucc.asn.au>
date Sun, 02 Jan 2005 17:09:26 +0000
parents d29b64170cf0
children d8254fc979e9
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1 #include <tommath.h>
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2 #ifdef BN_MP_TO_UNSIGNED_BIN_C
2
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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4 *
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5 * LibTomMath is a library that provides multiple-precision
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6 * integer arithmetic as well as number theoretic functionality.
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7 *
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8 * The library was designed directly after the MPI library by
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9 * Michael Fromberger but has been written from scratch with
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10 * additional optimizations in place.
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11 *
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12 * The library is free for all purposes without any express
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13 * guarantee it works.
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14 *
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15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
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16 */
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17
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18 /* store in unsigned [big endian] format */
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19 int
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20 mp_to_unsigned_bin (mp_int * a, unsigned char *b)
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21 {
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22 int x, res;
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23 mp_int t;
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24
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25 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
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26 return res;
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27 }
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28
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29 x = 0;
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30 while (mp_iszero (&t) == 0) {
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31 #ifndef MP_8BIT
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32 b[x++] = (unsigned char) (t.dp[0] & 255);
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33 #else
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34 b[x++] = (unsigned char) (t.dp[0] | ((t.dp[1] & 0x01) << 7));
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35 #endif
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36 if ((res = mp_div_2d (&t, 8, &t, NULL)) != MP_OKAY) {
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37 mp_clear (&t);
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38 return res;
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39 }
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40 }
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41 bn_reverse (b, x);
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42 mp_clear (&t);
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43 return MP_OKAY;
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44 }
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45 #endif