Mercurial > dropbear
annotate libtommath/bn_mp_decr.c @ 1723:5386011b740d
Disable toom and karatsuba for new libtommath
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 18 Jun 2020 19:12:07 +0800 |
parents | 1051e4eea25a |
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rev | line source |
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1692
1051e4eea25a
Update LibTomMath to 1.2.0 (#84)
Steffen Jaeckel <s@jaeckel.eu>
parents:
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1 #include "tommath_private.h" |
1051e4eea25a
Update LibTomMath to 1.2.0 (#84)
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2 #ifdef BN_MP_DECR_C |
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */ |
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4 /* SPDX-License-Identifier: Unlicense */ |
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5 |
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6 /* Decrement "a" by one like "a--". Changes input! */ |
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7 mp_err mp_decr(mp_int *a) |
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8 { |
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9 if (MP_IS_ZERO(a)) { |
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10 mp_set(a,1uL); |
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11 a->sign = MP_NEG; |
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12 return MP_OKAY; |
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13 } else if (a->sign == MP_NEG) { |
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14 mp_err err; |
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15 a->sign = MP_ZPOS; |
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16 if ((err = mp_incr(a)) != MP_OKAY) { |
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17 return err; |
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18 } |
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19 /* There is no -0 in LTM */ |
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20 if (!MP_IS_ZERO(a)) { |
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21 a->sign = MP_NEG; |
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22 } |
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23 return MP_OKAY; |
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24 } else if (a->dp[0] > 1uL) { |
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25 a->dp[0]--; |
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26 if (a->dp[0] == 0u) { |
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27 mp_zero(a); |
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28 } |
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29 return MP_OKAY; |
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30 } else { |
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31 return mp_sub_d(a, 1uL,a); |
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32 } |
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33 } |
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34 #endif |