Mercurial > dropbear
diff libtommath/bn_s_mp_get_bit.c @ 1692:1051e4eea25a
Update LibTomMath to 1.2.0 (#84)
* update C files
* update other files
* update headers
* update makefiles
* remove mp_set/get_double()
* use ltm 1.2.0 API
* update ltm_desc
* use bundled tommath if system-tommath is too old
* XMALLOC etc. were changed to MP_MALLOC etc.
| author | Steffen Jaeckel <s@jaeckel.eu> |
|---|---|
| date | Tue, 26 May 2020 17:36:47 +0200 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_s_mp_get_bit.c Tue May 26 17:36:47 2020 +0200 @@ -0,0 +1,21 @@ +#include "tommath_private.h" +#ifdef BN_S_MP_GET_BIT_C + +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ + +/* Get bit at position b and return MP_YES if the bit is 1, MP_NO if it is 0 */ +mp_bool s_mp_get_bit(const mp_int *a, unsigned int b) +{ + mp_digit bit; + int limb = (int)(b / MP_DIGIT_BIT); + + if (limb >= a->used) { + return MP_NO; + } + + bit = (mp_digit)1 << (b % MP_DIGIT_BIT); + return ((a->dp[limb] & bit) != 0u) ? MP_YES : MP_NO; +} + +#endif