diff options
Diffstat (limited to 'libtommath/bn_fast_s_mp_sqr.c')
| -rw-r--r-- | libtommath/bn_fast_s_mp_sqr.c | 90 |
1 files changed, 47 insertions, 43 deletions
diff --git a/libtommath/bn_fast_s_mp_sqr.c b/libtommath/bn_fast_s_mp_sqr.c index 1abf24b..161f785 100644 --- a/libtommath/bn_fast_s_mp_sqr.c +++ b/libtommath/bn_fast_s_mp_sqr.c @@ -1,4 +1,4 @@ -#include <tommath.h> +#include <tommath_private.h> #ifdef BN_FAST_S_MP_SQR_C /* LibTomMath, multiple-precision integer library -- Tom St Denis * @@ -12,36 +12,36 @@ * The library is free for all purposes without any express * guarantee it works. * - * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com + * Tom St Denis, tstdenis82@gmail.com, http://libtom.org */ /* the jist of squaring... - * you do like mult except the offset of the tmpx [one that - * starts closer to zero] can't equal the offset of tmpy. + * you do like mult except the offset of the tmpx [one that + * starts closer to zero] can't equal the offset of tmpy. * So basically you set up iy like before then you min it with - * (ty-tx) so that it never happens. You double all those + * (ty-tx) so that it never happens. You double all those * you add in the inner loop After that loop you do the squares and add them in. */ -int fast_s_mp_sqr (mp_int * a, mp_int * b) +int fast_s_mp_sqr(const mp_int *a, mp_int *b) { - int olduse, res, pa, ix, iz; - mp_digit W[MP_WARRAY], *tmpx; - mp_word W1; - - /* grow the destination as required */ - pa = a->used + a->used; - if (b->alloc < pa) { - if ((res = mp_grow (b, pa)) != MP_OKAY) { - return res; - } - } - - /* number of output digits to produce */ - W1 = 0; - for (ix = 0; ix < pa; ix++) { + int olduse, res, pa, ix, iz; + mp_digit W[MP_WARRAY], *tmpx; + mp_word W1; + + /* grow the destination as required */ + pa = a->used + a->used; + if (b->alloc < pa) { + if ((res = mp_grow(b, pa)) != MP_OKAY) { + return res; + } + } + + /* number of output digits to produce */ + W1 = 0; + for (ix = 0; ix < pa; ix++) { int tx, ty, iy; mp_word _W; mp_digit *tmpy; @@ -62,11 +62,11 @@ int fast_s_mp_sqr (mp_int * a, mp_int * b) */ iy = MIN(a->used-tx, ty+1); - /* now for squaring tx can never equal ty + /* now for squaring tx can never equal ty * we halve the distance since they approach at a rate of 2x * and we have to round because odd cases need to be executed */ - iy = MIN(iy, (ty-tx+1)>>1); + iy = MIN(iy, ((ty-tx)+1)>>1); /* execute loop */ for (iz = 0; iz < iy; iz++) { @@ -86,25 +86,29 @@ int fast_s_mp_sqr (mp_int * a, mp_int * b) /* make next carry */ W1 = _W >> ((mp_word)DIGIT_BIT); - } - - /* setup dest */ - olduse = b->used; - b->used = a->used+a->used; - - { - mp_digit *tmpb; - tmpb = b->dp; - for (ix = 0; ix < pa; ix++) { - *tmpb++ = W[ix] & MP_MASK; - } - - /* clear unused digits [that existed in the old copy of c] */ - for (; ix < olduse; ix++) { - *tmpb++ = 0; - } - } - mp_clamp (b); - return MP_OKAY; + } + + /* setup dest */ + olduse = b->used; + b->used = a->used+a->used; + + { + mp_digit *tmpb; + tmpb = b->dp; + for (ix = 0; ix < pa; ix++) { + *tmpb++ = W[ix] & MP_MASK; + } + + /* clear unused digits [that existed in the old copy of c] */ + for (; ix < olduse; ix++) { + *tmpb++ = 0; + } + } + mp_clamp(b); + return MP_OKAY; } #endif + +/* ref: $Format:%D$ */ +/* git commit: $Format:%H$ */ +/* commit time: $Format:%ai$ */ |