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annotate libtommath/bn_mp_signed_rsh.c @ 1843:03dfecca99bd

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author Matt Johnston <matt@ucc.asn.au>
date Mon, 18 Oct 2021 23:25:20 +0800
parents 1051e4eea25a
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1692
1051e4eea25a Update LibTomMath to 1.2.0 (#84)
Steffen Jaeckel <s@jaeckel.eu>
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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_SIGNED_RSH_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 /* shift right by a certain bit count with sign extension */
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7 mp_err mp_signed_rsh(const mp_int *a, int b, mp_int *c)
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8 {
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9 mp_err res;
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10 if (a->sign == MP_ZPOS) {
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11 return mp_div_2d(a, b, c, NULL);
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12 }
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13
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14 res = mp_add_d(a, 1uL, c);
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15 if (res != MP_OKAY) {
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16 return res;
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17 }
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18
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19 res = mp_div_2d(c, b, c, NULL);
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20 return (res == MP_OKAY) ? mp_sub_d(c, 1uL, c) : res;
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21 }
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22 #endif