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* bignum.c (bary_mul_karatsuba): Avoid duplicate calculation when

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squaring.
  ((bary_mul_toom3_branch): Ditto.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42001 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
akr 2013-07-16 09:37:42 +00:00
parent ed621c001e
commit c0cce2938c
2 changed files with 27 additions and 7 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
Tue Jul 16 18:35:48 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (bary_mul_karatsuba): Avoid duplicate calculation when
squaring.
((bary_mul_toom3_branch): Ditto.
Tue Jul 16 17:43:22 2013 Koichi Sasada <ko1@atdot.net>
* gc.c (link_free_heap_slot): removed.

14
bignum.c
View file

@ -1704,6 +1704,7 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yds,
int odd_y = 0;
int odd_xy = 0;
int sq;
BDIGIT *xds0, *xds1, *yds0, *yds1, *zds0, *zds1, *zds2, *zds3;
@ -1711,6 +1712,8 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yds,
assert(xl <= yl);
assert(yl < 2 * xl);
sq = xds == yds && xl == yl;
if (yl & 1) {
odd_y = 1;
yl--;
@ -1766,6 +1769,11 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yds,
/* zds0:|x1-x0| zds1:? zds2:? zds3:? wds:? */
if (sq) {
sub_p = 1;
bary_mul_karatsuba_start(zds1, 2*n, zds0, n, zds0, n, wds, wl);
}
else {
if (bary_sub(wds, n, yds, n, yds+n, n)) {
bary_2comp(wds, n);
sub_p = !sub_p;
@ -1774,6 +1782,7 @@ bary_mul_karatsuba(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yds,
/* zds0:|x1-x0| zds1:? zds2:? zds3:? wds:|y1-y0| */
bary_mul_karatsuba_start(zds1, 2*n, zds0, n, wds, n, wds+n, wl-n);
}
/* zds0:|x1-x0| zds1,zds2:|x1-x0|*|y1-y0| zds3:? wds:|y1-y0| */
@ -2029,8 +2038,13 @@ bary_mul_toom3_branch(BDIGIT *zds, size_t zl, BDIGIT *xds, size_t xl, BDIGIT *yd
VALUE x, y, z;
x = bignew(xl, 1);
MEMCPY(BDIGITS(x), xds, BDIGIT, xl);
if (xds == yds && xl == yl) {
y = x;
}
else {
y = bignew(yl, 1);
MEMCPY(BDIGITS(y), yds, BDIGIT, yl);
}
z = bigtrunc(bigmul1_toom3(x, y));
MEMCPY(zds, BDIGITS(z), BDIGIT, RBIGNUM_LEN(z));
MEMZERO(zds + RBIGNUM_LEN(z), BDIGIT, zl - RBIGNUM_LEN(z));