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* bignum.c (bigdivrem_mulsub): Extracted from bigdivrem1.

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(bigdivrem1): Use bary_add.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42119 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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akr 2013-07-22 16:36:36 +00:00
parent 1daf909bd7
commit 685e4c67bf
2 changed files with 42 additions and 22 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
Tue Jul 23 01:34:45 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (bigdivrem_mulsub): Extracted from bigdivrem1.
(bigdivrem1): Use bary_add.
Mon Jul 22 18:39:52 2013 Masaki Matsushita <glass.saga@gmail.com> Mon Jul 22 18:39:52 2013 Masaki Matsushita <glass.saga@gmail.com>
* string.c (rb_str_enumerate_chars): specify array capa * string.c (rb_str_enumerate_chars): specify array capa

59
bignum.c
View File

@ -5100,14 +5100,40 @@ struct big_div_struct {
volatile VALUE stop; volatile VALUE stop;
}; };
static BDIGIT_DBL_SIGNED
bigdivrem_mulsub(BDIGIT *zds, size_t zn, BDIGIT x, BDIGIT *yds, size_t yn)
{
size_t i;
BDIGIT_DBL t2;
BDIGIT_DBL_SIGNED num;
assert(zn == yn + 1);
num = 0;
t2 = 0;
i = 0;
do {
BDIGIT_DBL ee;
t2 += (BDIGIT_DBL)yds[i] * x;
ee = num - BIGLO(t2);
num = (BDIGIT_DBL)zds[i] + ee;
if (ee) zds[i] = BIGLO(num);
num = BIGDN(num);
t2 = BIGDN(t2);
} while (++i < yn);
num += zds[i] - t2; /* borrow from high digit; don't update */
return num;
}
static void * static void *
bigdivrem1(void *ptr) bigdivrem1(void *ptr)
{ {
struct big_div_struct *bds = (struct big_div_struct*)ptr; struct big_div_struct *bds = (struct big_div_struct*)ptr;
long ny = bds->ny; long ny = bds->ny;
long i, j; long j;
long nyzero = bds->nyzero;
BDIGIT *yds = bds->yds, *zds = bds->zds; BDIGIT *yds = bds->yds, *zds = bds->zds;
BDIGIT_DBL t2;
BDIGIT_DBL_SIGNED num; BDIGIT_DBL_SIGNED num;
BDIGIT q; BDIGIT q;
@ -5120,26 +5146,15 @@ bigdivrem1(void *ptr)
if (zds[j] == yds[ny-1]) q = BDIGMAX; if (zds[j] == yds[ny-1]) q = BDIGMAX;
else q = (BDIGIT)((BIGUP(zds[j]) + zds[j-1])/yds[ny-1]); else q = (BDIGIT)((BIGUP(zds[j]) + zds[j-1])/yds[ny-1]);
if (q) { if (q) {
i = bds->nyzero; num = 0; t2 = 0; num = bigdivrem_mulsub(zds+j-(ny-nyzero), ny-nyzero+1,
do { /* multiply and subtract */ q,
BDIGIT_DBL ee; yds+nyzero, ny-nyzero);
t2 += (BDIGIT_DBL)yds[i] * q; while (num) { /* "add back" required */
ee = num - BIGLO(t2); q--;
num = (BDIGIT_DBL)zds[j - ny + i] + ee; num = bary_add(zds+j-(ny-nyzero), ny-nyzero,
if (ee) zds[j - ny + i] = BIGLO(num); zds+j-(ny-nyzero), ny-nyzero,
num = BIGDN(num); yds+nyzero, ny-nyzero);
t2 = BIGDN(t2); num--;
} while (++i < ny);
num += zds[j - ny + i] - t2;/* borrow from high digit; don't update */
while (num) { /* "add back" required */
i = 0; num = 0; q--;
do {
BDIGIT_DBL ee = num + yds[i];
num = (BDIGIT_DBL)zds[j - ny + i] + ee;
if (ee) zds[j - ny + i] = BIGLO(num);
num = BIGDN(num);
} while (++i < ny);
num--;
} }
} }
zds[j] = q; zds[j] = q;