py: Improve mpz_and function.
This should now have correct (and optimal) behaviour.
diff --git a/py/mpz.c b/py/mpz.c
index 25c32e9..9e60fc5 100644
--- a/py/mpz.c
+++ b/py/mpz.c
@@ -207,17 +207,15 @@
STATIC uint mpn_and(mpz_dig_t *idig, const mpz_dig_t *jdig, uint jlen, const mpz_dig_t *kdig, uint klen) {
mpz_dig_t *oidig = idig;
- jlen -= klen;
-
for (; klen > 0; --klen, ++idig, ++jdig, ++kdig) {
*idig = *jdig & *kdig;
}
// remove trailing zeros
- for (; idig > oidig && *idig == 0; --idig) {
+ for (--idig; idig >= oidig && *idig == 0; --idig) {
}
- return idig - oidig;
+ return idig + 1 - oidig;
}
/* computes i = j | k
@@ -898,14 +896,15 @@
can have dest, lhs, rhs the same
*/
void mpz_and_inpl(mpz_t *dest, const mpz_t *lhs, const mpz_t *rhs) {
- if (mpn_cmp(lhs->dig, lhs->len, rhs->dig, rhs->len) < 0) {
+ // make sure lhs has the most digits
+ if (lhs->len < rhs->len) {
const mpz_t *temp = lhs;
lhs = rhs;
rhs = temp;
}
if (lhs->neg == rhs->neg) {
- mpz_need_dig(dest, lhs->len);
+ mpz_need_dig(dest, rhs->len);
dest->len = mpn_and(dest->dig, lhs->dig, lhs->len, rhs->dig, rhs->len);
} else {
mpz_need_dig(dest, lhs->len);