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1) Use _mpd_basedivmod() regardless of the length of the dividend. This is

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required for a corner case in dec_hash() in the following commit and also
   usually faster. dec_hash() needs some extra precision above MPD_MAX_PREC,
   and _mpd_base_ndivmod() is not audited for that.

2) Use _mpd_basemul() if the length of the smaller operand is less than
   or equal to 256. While this is technically an optimization, it is
   required for *testing* corner cases in dec_hash() in reasonable time.
This commit is contained in:
Stefan Krah 2012-08-22 18:54:37 +02:00
parent ad54c6d82e
commit 2fd502f6a1
1 changed files with 9 additions and 6 deletions
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15
Modules/_decimal/libmpdec/mpdecimal.c
View file

@ -3513,8 +3513,7 @@ _mpd_qdiv(int action, mpd_t *q, const mpd_t *a, const mpd_t *b,
if (b->len == 1) {
rem = _mpd_shortdiv(q->data, a->data, a->len, b->data[0]);
}
else if (a->len < 2*MPD_NEWTONDIV_CUTOFF &&
b->len < MPD_NEWTONDIV_CUTOFF) {
else if (b->len <= MPD_NEWTONDIV_CUTOFF) {
int ret = _mpd_basedivmod(q->data, NULL, a->data, b->data,
a->len, b->len);
if (ret < 0) {
@ -3667,8 +3666,7 @@ _mpd_qdivmod(mpd_t *q, mpd_t *r, const mpd_t *a, const mpd_t *b,
r->data[0] = _mpd_shortdiv(q->data, a->data, a->len, b->data[0]);
}
}
else if (a->len < 2*MPD_NEWTONDIV_CUTOFF &&
b->len < MPD_NEWTONDIV_CUTOFF) {
else if (b->len <= MPD_NEWTONDIV_CUTOFF) {
int ret;
ret = _mpd_basedivmod(q->data, r->data, a->data, b->data,
a->len, b->len);
@ -5544,10 +5542,15 @@ _mpd_qmul(mpd_t *result, const mpd_t *a, const mpd_t *b,
}
if (small->len == 1) {
if (small->len <= 256) {
rdata = mpd_calloc(rsize, sizeof *rdata);
if (rdata != NULL) {
_mpd_shortmul(rdata, big->data, big->len, small->data[0]);
if (small->len == 1) {
_mpd_shortmul(rdata, big->data, big->len, small->data[0]);
}
else {
_mpd_basemul(rdata, small->data, big->data, small->len, big->len);
}
}
}
else if (rsize <= 1024) {