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author | Kevin B Kenny <kennykb@acm.org> | 2005-04-10 23:54:55 (GMT) |
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committer | Kevin B Kenny <kennykb@acm.org> | 2005-04-10 23:54:55 (GMT) |
commit | d2b645df1ab7b43093f7553808c64fedaa3b3a49 (patch) | |
tree | 99103342350cd1fb4776a60684221ad722fdec52 /libtommath/bn_fast_s_mp_sqr.c | |
parent | b9cf65a08e6a59e434685e894e3189c201ac6791 (diff) | |
download | tcl-d2b645df1ab7b43093f7553808c64fedaa3b3a49.zip tcl-d2b645df1ab7b43093f7553808c64fedaa3b3a49.tar.gz tcl-d2b645df1ab7b43093f7553808c64fedaa3b3a49.tar.bz2 |
Import of tommath 0.35
Diffstat (limited to 'libtommath/bn_fast_s_mp_sqr.c')
-rw-r--r-- | libtommath/bn_fast_s_mp_sqr.c | 33 |
1 files changed, 7 insertions, 26 deletions
diff --git a/libtommath/bn_fast_s_mp_sqr.c b/libtommath/bn_fast_s_mp_sqr.c index d6014ab..66a2942 100644 --- a/libtommath/bn_fast_s_mp_sqr.c +++ b/libtommath/bn_fast_s_mp_sqr.c @@ -15,33 +15,14 @@ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org */ -/* fast squaring - * - * This is the comba method where the columns of the product - * are computed first then the carries are computed. This - * has the effect of making a very simple inner loop that - * is executed the most - * - * W2 represents the outer products and W the inner. - * - * A further optimizations is made because the inner - * products are of the form "A * B * 2". The *2 part does - * not need to be computed until the end which is good - * because 64-bit shifts are slow! - * - * Based on Algorithm 14.16 on pp.597 of HAC. - * - */ /* 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. So basically you set up iy like before then you min it with -(ty-tx) so that it never happens. You double all those you add in the inner loop + * 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 + * you add in the inner loop After that loop you do the squares and add them in. - -Remove W2 and don't memset W - */ int fast_s_mp_sqr (mp_int * a, mp_int * b) @@ -76,7 +57,7 @@ int fast_s_mp_sqr (mp_int * a, mp_int * b) tmpx = a->dp + tx; tmpy = a->dp + ty; - /* this is the number of times the loop will iterrate, essentially its + /* this is the number of times the loop will iterrate, essentially while (tx++ < a->used && ty-- >= 0) { ... } */ iy = MIN(a->used-tx, ty+1); @@ -101,7 +82,7 @@ int fast_s_mp_sqr (mp_int * a, mp_int * b) } /* store it */ - W[ix] = _W; + W[ix] = (mp_digit)(_W & MP_MASK); /* make next carry */ W1 = _W >> ((mp_word)DIGIT_BIT); |