diff options
Diffstat (limited to 'libtommath/bn_mp_add_d.c')
| -rw-r--r-- | libtommath/bn_mp_add_d.c | 50 |
1 files changed, 15 insertions, 35 deletions
diff --git a/libtommath/bn_mp_add_d.c b/libtommath/bn_mp_add_d.c index e626c9a..f301575 100644 --- a/libtommath/bn_mp_add_d.c +++ b/libtommath/bn_mp_add_d.c @@ -1,27 +1,19 @@ #include "tommath_private.h" #ifdef BN_MP_ADD_D_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 - */ +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ /* single digit addition */ -int mp_add_d(const mp_int *a, mp_digit b, mp_int *c) +mp_err mp_add_d(const mp_int *a, mp_digit b, mp_int *c) { - int res, ix, oldused; - mp_digit *tmpa, *tmpc, mu; + mp_err err; + int ix, oldused; + mp_digit *tmpa, *tmpc; /* grow c as required */ if (c->alloc < (a->used + 1)) { - if ((res = mp_grow(c, a->used + 1)) != MP_OKAY) { - return res; + if ((err = mp_grow(c, a->used + 1)) != MP_OKAY) { + return err; } } @@ -32,7 +24,7 @@ int mp_add_d(const mp_int *a, mp_digit b, mp_int *c) a_.sign = MP_ZPOS; /* c = |a| - b */ - res = mp_sub_d(&a_, b, c); + err = mp_sub_d(&a_, b, c); /* fix sign */ c->sign = MP_NEG; @@ -40,7 +32,7 @@ int mp_add_d(const mp_int *a, mp_digit b, mp_int *c) /* clamp */ mp_clamp(c); - return res; + return err; } /* old number of used digits in c */ @@ -54,17 +46,11 @@ int mp_add_d(const mp_int *a, mp_digit b, mp_int *c) /* if a is positive */ if (a->sign == MP_ZPOS) { - /* add digit, after this we're propagating - * the carry. - */ - *tmpc = *tmpa++ + b; - mu = *tmpc >> DIGIT_BIT; - *tmpc++ &= MP_MASK; - - /* now handle rest of the digits */ - for (ix = 1; ix < a->used; ix++) { + /* add digits, mu is carry */ + mp_digit mu = b; + for (ix = 0; ix < a->used; ix++) { *tmpc = *tmpa++ + mu; - mu = *tmpc >> DIGIT_BIT; + mu = *tmpc >> MP_DIGIT_BIT; *tmpc++ &= MP_MASK; } /* set final carry */ @@ -94,16 +80,10 @@ int mp_add_d(const mp_int *a, mp_digit b, mp_int *c) c->sign = MP_ZPOS; /* now zero to oldused */ - while (ix++ < oldused) { - *tmpc++ = 0; - } + MP_ZERO_DIGITS(tmpc, oldused - ix); 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 */ |