diff options
Diffstat (limited to 'libtommath/bn_s_mp_sqr.c')
| -rw-r--r-- | libtommath/bn_s_mp_sqr.c | 119 |
1 files changed, 52 insertions, 67 deletions
diff --git a/libtommath/bn_s_mp_sqr.c b/libtommath/bn_s_mp_sqr.c index ac0e157..505c9f0 100644 --- a/libtommath/bn_s_mp_sqr.c +++ b/libtommath/bn_s_mp_sqr.c @@ -1,84 +1,69 @@ -#include <tommath_private.h> +#include "tommath_private.h" #ifdef BN_S_MP_SQR_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 */ /* low level squaring, b = a*a, HAC pp.596-597, Algorithm 14.16 */ -int s_mp_sqr (mp_int * a, mp_int * b) +mp_err s_mp_sqr(const mp_int *a, mp_int *b) { - mp_int t; - int res, ix, iy, pa; - mp_word r; - mp_digit u, tmpx, *tmpt; + mp_int t; + int ix, iy, pa; + mp_err err; + mp_word r; + mp_digit u, tmpx, *tmpt; - pa = a->used; - if ((res = mp_init_size (&t, (2 * pa) + 1)) != MP_OKAY) { - return res; - } + pa = a->used; + if ((err = mp_init_size(&t, (2 * pa) + 1)) != MP_OKAY) { + return err; + } - /* default used is maximum possible size */ - t.used = (2 * pa) + 1; + /* default used is maximum possible size */ + t.used = (2 * pa) + 1; - for (ix = 0; ix < pa; ix++) { - /* first calculate the digit at 2*ix */ - /* calculate double precision result */ - r = (mp_word)t.dp[2*ix] + - ((mp_word)a->dp[ix] * (mp_word)a->dp[ix]); + for (ix = 0; ix < pa; ix++) { + /* first calculate the digit at 2*ix */ + /* calculate double precision result */ + r = (mp_word)t.dp[2*ix] + + ((mp_word)a->dp[ix] * (mp_word)a->dp[ix]); - /* store lower part in result */ - t.dp[ix+ix] = (mp_digit) (r & ((mp_word) MP_MASK)); + /* store lower part in result */ + t.dp[ix+ix] = (mp_digit)(r & (mp_word)MP_MASK); - /* get the carry */ - u = (mp_digit)(r >> ((mp_word) DIGIT_BIT)); + /* get the carry */ + u = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT); - /* left hand side of A[ix] * A[iy] */ - tmpx = a->dp[ix]; + /* left hand side of A[ix] * A[iy] */ + tmpx = a->dp[ix]; - /* alias for where to store the results */ - tmpt = t.dp + ((2 * ix) + 1); - - for (iy = ix + 1; iy < pa; iy++) { - /* first calculate the product */ - r = ((mp_word)tmpx) * ((mp_word)a->dp[iy]); + /* alias for where to store the results */ + tmpt = t.dp + ((2 * ix) + 1); - /* now calculate the double precision result, note we use - * addition instead of *2 since it's easier to optimize - */ - r = ((mp_word) *tmpt) + r + r + ((mp_word) u); + for (iy = ix + 1; iy < pa; iy++) { + /* first calculate the product */ + r = (mp_word)tmpx * (mp_word)a->dp[iy]; - /* store lower part */ - *tmpt++ = (mp_digit) (r & ((mp_word) MP_MASK)); + /* now calculate the double precision result, note we use + * addition instead of *2 since it's easier to optimize + */ + r = (mp_word)*tmpt + r + r + (mp_word)u; - /* get carry */ - u = (mp_digit)(r >> ((mp_word) DIGIT_BIT)); - } - /* propagate upwards */ - while (u != ((mp_digit) 0)) { - r = ((mp_word) *tmpt) + ((mp_word) u); - *tmpt++ = (mp_digit) (r & ((mp_word) MP_MASK)); - u = (mp_digit)(r >> ((mp_word) DIGIT_BIT)); - } - } + /* store lower part */ + *tmpt++ = (mp_digit)(r & (mp_word)MP_MASK); - mp_clamp (&t); - mp_exch (&t, b); - mp_clear (&t); - return MP_OKAY; + /* get carry */ + u = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT); + } + /* propagate upwards */ + while (u != 0uL) { + r = (mp_word)*tmpt + (mp_word)u; + *tmpt++ = (mp_digit)(r & (mp_word)MP_MASK); + u = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT); + } + } + + mp_clamp(&t); + mp_exch(&t, b); + mp_clear(&t); + return MP_OKAY; } #endif - -/* ref: $Format:%D$ */ -/* git commit: $Format:%H$ */ -/* commit time: $Format:%ai$ */ |