diff options
Diffstat (limited to 'libtommath/bn_mp_or.c')
-rw-r--r-- | libtommath/bn_mp_or.c | 82 |
1 files changed, 45 insertions, 37 deletions
diff --git a/libtommath/bn_mp_or.c b/libtommath/bn_mp_or.c index 0e092be..cdacbfb 100644 --- a/libtommath/bn_mp_or.c +++ b/libtommath/bn_mp_or.c @@ -1,48 +1,56 @@ #include "tommath_private.h" #ifdef BN_MP_OR_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 - */ - -/* OR two ints together */ -int mp_or(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 or */ +mp_err mp_or(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 == MP_NEG) || (b->sign == MP_NEG)) ? 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 */ |