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author | jan.nijtmans <nijtmans@users.sourceforge.net> | 2019-02-01 20:00:04 (GMT) |
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committer | jan.nijtmans <nijtmans@users.sourceforge.net> | 2019-02-01 20:00:04 (GMT) |
commit | 04ed7f99daa6ac1ca3e5a2903fc7c9325cd4d581 (patch) | |
tree | f20c21e7a9b452eeab3f8cace2601ec59404aed7 /libtommath/bn_mp_tc_xor.c | |
parent | 99be2974c327e7b37412b3f6c11681bffc3abb31 (diff) | |
download | tcl-04ed7f99daa6ac1ca3e5a2903fc7c9325cd4d581.zip tcl-04ed7f99daa6ac1ca3e5a2903fc7c9325cd4d581.tar.gz tcl-04ed7f99daa6ac1ca3e5a2903fc7c9325cd4d581.tar.bz2 |
Update libtommath to latest stable release (1.1.0)
Diffstat (limited to 'libtommath/bn_mp_tc_xor.c')
-rw-r--r-- | libtommath/bn_mp_tc_xor.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/libtommath/bn_mp_tc_xor.c b/libtommath/bn_mp_tc_xor.c new file mode 100644 index 0000000..cdb1d40 --- /dev/null +++ b/libtommath/bn_mp_tc_xor.c @@ -0,0 +1,90 @@ +#include "tommath_private.h" +#ifdef BN_MP_TC_XOR_C +/* LibTomMath, multiple-precision integer library -- Tom St Denis + * + * LibTomMath is a library that provides multiple-precision + * integer arithmetic as well as number theoretic functionality. + * + * The library was designed directly after the MPI library by + * Michael Fromberger but has been written from scratch with + * additional optimizations in place. + * + * SPDX-License-Identifier: Unlicense + */ + +/* two complement xor */ +int mp_tc_xor(const mp_int *a, const mp_int *b, mp_int *c) +{ + int res = MP_OKAY, bits, abits, bbits; + int as = mp_isneg(a), bs = mp_isneg(b); + mp_int *mx = NULL, _mx, acpy, bcpy; + + if ((as != MP_NO) || (bs != MP_NO)) { + abits = mp_count_bits(a); + bbits = mp_count_bits(b); + bits = MAX(abits, bbits); + res = mp_init_set_int(&_mx, 1uL); + if (res != MP_OKAY) { + goto end; + } + + mx = &_mx; + res = mp_mul_2d(mx, bits + 1, mx); + if (res != MP_OKAY) { + goto end; + } + + if (as != MP_NO) { + res = mp_init(&acpy); + if (res != MP_OKAY) { + goto end; + } + + res = mp_add(mx, a, &acpy); + if (res != MP_OKAY) { + mp_clear(&acpy); + goto end; + } + a = &acpy; + } + if (bs != MP_NO) { + res = mp_init(&bcpy); + if (res != MP_OKAY) { + goto end; + } + + res = mp_add(mx, b, &bcpy); + if (res != MP_OKAY) { + mp_clear(&bcpy); + goto end; + } + b = &bcpy; + } + } + + res = mp_xor(a, b, c); + + if ((as != bs) && (res == MP_OKAY)) { + res = mp_sub(c, mx, c); + } + +end: + if (a == &acpy) { + mp_clear(&acpy); + } + + if (b == &bcpy) { + mp_clear(&bcpy); + } + + if (mx == &_mx) { + mp_clear(mx); + } + + return res; +} +#endif + +/* ref: $Format:%D$ */ +/* git commit: $Format:%H$ */ +/* commit time: $Format:%ai$ */ |