diff options
Diffstat (limited to 'libtommath/bn_mp_mul_2d.c')
-rw-r--r-- | libtommath/bn_mp_mul_2d.c | 108 |
1 files changed, 55 insertions, 53 deletions
diff --git a/libtommath/bn_mp_mul_2d.c b/libtommath/bn_mp_mul_2d.c index 4ac2e4e..42c6535 100644 --- a/libtommath/bn_mp_mul_2d.c +++ b/libtommath/bn_mp_mul_2d.c @@ -1,4 +1,4 @@ -#include <tommath.h> +#include "tommath_private.h" #ifdef BN_MP_MUL_2D_C /* LibTomMath, multiple-precision integer library -- Tom St Denis * @@ -11,71 +11,73 @@ * * The library is free for all purposes without any express * guarantee it works. - * - * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com */ /* shift left by a certain bit count */ -int mp_mul_2d (const mp_int * a, int b, mp_int * c) +int mp_mul_2d(const mp_int *a, int b, mp_int *c) { - mp_digit d; - int res; + mp_digit d; + int res; + + /* copy */ + if (a != c) { + if ((res = mp_copy(a, c)) != MP_OKAY) { + return res; + } + } - /* copy */ - if (a != c) { - if ((res = mp_copy (a, c)) != MP_OKAY) { - return res; - } - } + if (c->alloc < (c->used + (b / DIGIT_BIT) + 1)) { + if ((res = mp_grow(c, c->used + (b / DIGIT_BIT) + 1)) != MP_OKAY) { + return res; + } + } - if (c->alloc < (int)(c->used + b/DIGIT_BIT + 1)) { - if ((res = mp_grow (c, c->used + b / DIGIT_BIT + 1)) != MP_OKAY) { - return res; - } - } + /* shift by as many digits in the bit count */ + if (b >= DIGIT_BIT) { + if ((res = mp_lshd(c, b / DIGIT_BIT)) != MP_OKAY) { + return res; + } + } - /* shift by as many digits in the bit count */ - if (b >= (int)DIGIT_BIT) { - if ((res = mp_lshd (c, b / DIGIT_BIT)) != MP_OKAY) { - return res; - } - } + /* shift any bit count < DIGIT_BIT */ + d = (mp_digit)(b % DIGIT_BIT); + if (d != 0u) { + mp_digit *tmpc, shift, mask, r, rr; + int x; - /* shift any bit count < DIGIT_BIT */ - d = (mp_digit) (b % DIGIT_BIT); - if (d != 0) { - register mp_digit *tmpc, shift, mask, r, rr; - register int x; + /* bitmask for carries */ + mask = ((mp_digit)1 << d) - (mp_digit)1; - /* bitmask for carries */ - mask = (((mp_digit)1) << d) - 1; + /* shift for msbs */ + shift = (mp_digit)DIGIT_BIT - d; - /* shift for msbs */ - shift = DIGIT_BIT - d; + /* alias */ + tmpc = c->dp; - /* alias */ - tmpc = c->dp; + /* carry */ + r = 0; + for (x = 0; x < c->used; x++) { + /* get the higher bits of the current word */ + rr = (*tmpc >> shift) & mask; - /* carry */ - r = 0; - for (x = 0; x < c->used; x++) { - /* get the higher bits of the current word */ - rr = (*tmpc >> shift) & mask; + /* shift the current word and OR in the carry */ + *tmpc = ((*tmpc << d) | r) & MP_MASK; + ++tmpc; - /* shift the current word and OR in the carry */ - *tmpc = ((*tmpc << d) | r) & MP_MASK; - ++tmpc; + /* set the carry to the carry bits of the current word */ + r = rr; + } - /* set the carry to the carry bits of the current word */ - r = rr; - } - - /* set final carry */ - if (r != 0) { - c->dp[(c->used)++] = r; - } - } - mp_clamp (c); - return MP_OKAY; + /* set final carry */ + if (r != 0u) { + c->dp[(c->used)++] = r; + } + } + mp_clamp(c); + return MP_OKAY; } #endif + +/* ref: $Format:%D$ */ +/* git commit: $Format:%H$ */ +/* commit time: $Format:%ai$ */ |