diff options
author | Steffen Jaeckel <s@jaeckel.eu> | 2020-05-26 17:36:47 +0200 |
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committer | GitHub <noreply@github.com> | 2020-05-26 23:36:47 +0800 |
commit | b4bd23b4d2a4c640880b49069e02cd598dd03416 (patch) | |
tree | fb480b4e501cc69b305de95fb15259aa6afa1963 /libtommath/bn_mp_xor.c | |
parent | 724e61f8ae9e9f216b0252e41c5ebd5d64ad79a6 (diff) |
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.
Diffstat (limited to 'libtommath/bn_mp_xor.c')
-rw-r--r-- | libtommath/bn_mp_xor.c | 82 |
1 files changed, 45 insertions, 37 deletions
diff --git a/libtommath/bn_mp_xor.c b/libtommath/bn_mp_xor.c index 95b56a1..71e7ca1 100644 --- a/libtommath/bn_mp_xor.c +++ b/libtommath/bn_mp_xor.c @@ -1,48 +1,56 @@ #include "tommath_private.h" #ifdef BN_MP_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 - */ - -/* XOR two ints together */ -int mp_xor(const mp_int *a, const mp_int *b, mp_int *c) +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ + +/* two complement xor */ +mp_err mp_xor(const mp_int *a, const mp_int *b, mp_int *c) { - int res, ix, px; - mp_int t; - const mp_int *x; + int used = MP_MAX(a->used, b->used) + 1, i; + mp_err err; + mp_digit ac = 1, bc = 1, cc = 1; + mp_sign csign = (a->sign != b->sign) ? MP_NEG : MP_ZPOS; - if (a->used > b->used) { - if ((res = mp_init_copy(&t, a)) != MP_OKAY) { - return res; - } - px = b->used; - x = b; - } else { - if ((res = mp_init_copy(&t, b)) != MP_OKAY) { - return res; + if (c->alloc < used) { + if ((err = mp_grow(c, used)) != MP_OKAY) { + return err; } - px = a->used; - x = a; } - for (ix = 0; ix < px; ix++) { - t.dp[ix] ^= x->dp[ix]; + for (i = 0; i < used; i++) { + mp_digit x, y; + + /* convert to two complement if negative */ + if (a->sign == MP_NEG) { + ac += (i >= a->used) ? MP_MASK : (~a->dp[i] & MP_MASK); + x = ac & MP_MASK; + ac >>= MP_DIGIT_BIT; + } else { + x = (i >= a->used) ? 0uL : a->dp[i]; + } + + /* convert to two complement if negative */ + if (b->sign == MP_NEG) { + bc += (i >= b->used) ? MP_MASK : (~b->dp[i] & MP_MASK); + y = bc & MP_MASK; + bc >>= MP_DIGIT_BIT; + } else { + y = (i >= b->used) ? 0uL : b->dp[i]; + } + + c->dp[i] = x ^ y; + + /* convert to to sign-magnitude if negative */ + if (csign == MP_NEG) { + cc += ~c->dp[i] & MP_MASK; + c->dp[i] = cc & MP_MASK; + cc >>= MP_DIGIT_BIT; + } } - mp_clamp(&t); - mp_exch(c, &t); - mp_clear(&t); + + c->used = used; + c->sign = csign; + mp_clamp(c); return MP_OKAY; } #endif - -/* ref: HEAD -> master, tag: v1.1.0 */ -/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ -/* commit time: 2019-01-28 20:32:32 +0100 */ |