diff options
author | Matt Johnston <matt@ucc.asn.au> | 2020-10-15 19:55:15 +0800 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2020-10-15 19:55:15 +0800 |
commit | 0e3e8db5bfca0c579be55e7580a46c593c1384be (patch) | |
tree | 2b1a718f633fb95c1f2d689a591cf9e8642697f3 /libtommath/bn_mp_mul_2.c | |
parent | 78e17f6ee9a944430da3e517ee1fe384fd6b275b (diff) | |
parent | 17873e8c922eded2cec86184673a6d110df6403f (diff) |
merge from main
--HG--
branch : fuzz
Diffstat (limited to 'libtommath/bn_mp_mul_2.c')
-rw-r--r-- | libtommath/bn_mp_mul_2.c | 120 |
1 files changed, 51 insertions, 69 deletions
diff --git a/libtommath/bn_mp_mul_2.c b/libtommath/bn_mp_mul_2.c index d22fd89..bc0691a 100644 --- a/libtommath/bn_mp_mul_2.c +++ b/libtommath/bn_mp_mul_2.c @@ -1,82 +1,64 @@ -#include <tommath_private.h> +#include "tommath_private.h" #ifdef BN_MP_MUL_2_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. - * - * The library is free for all purposes without any express - * guarantee it works. - * - * Tom St Denis, tstdenis82@gmail.com, http://libtom.org - */ +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ /* b = a*2 */ -int mp_mul_2(mp_int * a, mp_int * b) +mp_err mp_mul_2(const mp_int *a, mp_int *b) { - int x, res, oldused; + int x, oldused; + mp_err err; - /* grow to accomodate result */ - if (b->alloc < (a->used + 1)) { - if ((res = mp_grow (b, a->used + 1)) != MP_OKAY) { - return res; - } - } + /* grow to accomodate result */ + if (b->alloc < (a->used + 1)) { + if ((err = mp_grow(b, a->used + 1)) != MP_OKAY) { + return err; + } + } - oldused = b->used; - b->used = a->used; + oldused = b->used; + b->used = a->used; - { - mp_digit r, rr, *tmpa, *tmpb; + { + mp_digit r, rr, *tmpa, *tmpb; - /* alias for source */ - tmpa = a->dp; - - /* alias for dest */ - tmpb = b->dp; + /* alias for source */ + tmpa = a->dp; - /* carry */ - r = 0; - for (x = 0; x < a->used; x++) { - - /* get what will be the *next* carry bit from the - * MSB of the current digit - */ - rr = *tmpa >> ((mp_digit)(DIGIT_BIT - 1)); - - /* now shift up this digit, add in the carry [from the previous] */ - *tmpb++ = ((*tmpa++ << ((mp_digit)1)) | r) & MP_MASK; - - /* copy the carry that would be from the source - * digit into the next iteration - */ - r = rr; - } + /* alias for dest */ + tmpb = b->dp; + + /* carry */ + r = 0; + for (x = 0; x < a->used; x++) { + + /* get what will be the *next* carry bit from the + * MSB of the current digit + */ + rr = *tmpa >> (mp_digit)(MP_DIGIT_BIT - 1); - /* new leading digit? */ - if (r != 0) { - /* add a MSB which is always 1 at this point */ - *tmpb = 1; - ++(b->used); - } + /* now shift up this digit, add in the carry [from the previous] */ + *tmpb++ = ((*tmpa++ << 1uL) | r) & MP_MASK; - /* now zero any excess digits on the destination - * that we didn't write to - */ - tmpb = b->dp + b->used; - for (x = b->used; x < oldused; x++) { - *tmpb++ = 0; - } - } - b->sign = a->sign; - return MP_OKAY; + /* copy the carry that would be from the source + * digit into the next iteration + */ + r = rr; + } + + /* new leading digit? */ + if (r != 0u) { + /* add a MSB which is always 1 at this point */ + *tmpb = 1; + ++(b->used); + } + + /* now zero any excess digits on the destination + * that we didn't write to + */ + MP_ZERO_DIGITS(b->dp + b->used, oldused - b->used); + } + b->sign = a->sign; + return MP_OKAY; } #endif - -/* ref: $Format:%D$ */ -/* git commit: $Format:%H$ */ -/* commit time: $Format:%ai$ */ |