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optimized the bigint division a bit more

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hyunghwan.chung
2019-03-25 11:41:26 +00:00
parent 983026c774
commit 45b21a004b
2 changed files with 100 additions and 35 deletions
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114
moo/lib/bigint.c
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@ -2192,47 +2192,91 @@ moo_oop_t moo_divints (moo_t* moo, moo_oop_t x, moo_oop_t y, int modulo, moo_oop
return z;
default:
/* TODO: do division by shifting if both x & y are negative here */
if (yv > 0 && IS_POW2(yv) && !MOO_POINTER_IS_NBIGINT(moo, x))
/* TODO: do division by shifting if both x & y are in different sign */
if (yv < 0)
{
moo_oow_t nshifts;
/*
2**x = v
x = log2(v)
x is the number of shift to make */
nshifts = LOG2_FOR_POW2(yv);
moo_pushvolat (moo, &x);
moo_pushvolat (moo, &y);
z = clone_bigint(moo, x, MOO_OBJ_GET_SIZE(x));
moo_popvolats (moo, 2);
if (!z) return MOO_NULL;
rshift_unsigned_array (MOO_OBJ_GET_LIWORD_SLOT(z), MOO_OBJ_GET_SIZE(z), nshifts);
moo_pushvolat (moo, &x);
moo_pushvolat (moo, &y);
z = normalize_bigint(moo, z);
moo_popvolats (moo, 2);
if (!z) return MOO_NULL;
if (rem)
moo_oow_t yv_neg = -yv;
if (IS_POW2(yv_neg) && MOO_POINTER_IS_NBIGINT(moo, x))
{
moo_oow_t nshifts;
nshifts = LOG2_FOR_POW2(yv_neg);
moo_pushvolat (moo, &x);
moo_pushvolat (moo, &z);
r = moo_mulints(moo, y, z);
moo_popvolats (moo, 2);
if (!r) return MOO_NULL;
moo_pushvolat (moo, &z);
r = moo_subints(moo, x, r);
z = clone_bigint_negated(moo, x, MOO_OBJ_GET_SIZE(x));
moo_popvolat (moo);
if (!r) return MOO_NULL;
if (!z) return MOO_NULL;
*rem = r;
rshift_unsigned_array (MOO_OBJ_GET_LIWORD_SLOT(z), MOO_OBJ_GET_SIZE(z), nshifts);
moo_pushvolat (moo, &x);
z = normalize_bigint(moo, z);
moo_popvolat (moo);
if (!z) return MOO_NULL;
if (rem)
{
moo_pushvolat (moo, &x);
moo_pushvolat (moo, &z);
r = moo_mulints(moo, MOO_SMOOI_TO_OOP(yv_neg), z);
moo_popvolats (moo, 2);
if (!r) return MOO_NULL;
moo_pushvolat (moo, &z);
r = moo_addints(moo, x, r);
moo_popvolat (moo);
if (!r) return MOO_NULL;
*rem = r;
}
return z;
}
}
else
{
/* yv > 0 */
if (IS_POW2(yv) && MOO_POINTER_IS_PBIGINT(moo, x))
{
moo_oow_t nshifts;
/*
2**x = v
x = log2(v)
x is the number of shift to make */
nshifts = LOG2_FOR_POW2(yv);
/* no pushvolat() on y as y is SMOOI here */
moo_pushvolat (moo, &x);
z = clone_bigint(moo, x, MOO_OBJ_GET_SIZE(x));
moo_popvolat (moo);
if (!z) return MOO_NULL;
rshift_unsigned_array (MOO_OBJ_GET_LIWORD_SLOT(z), MOO_OBJ_GET_SIZE(z), nshifts);
moo_pushvolat (moo, &x);
z = normalize_bigint(moo, z);
moo_popvolat (moo);
if (!z) return MOO_NULL;
if (rem)
{
moo_pushvolat (moo, &x);
moo_pushvolat (moo, &z);
r = moo_mulints(moo, y, z);
moo_popvolats (moo, 2);
if (!r) return MOO_NULL;
moo_pushvolat (moo, &z);
r = moo_subints(moo, x, r);
moo_popvolat (moo);
if (!r) return MOO_NULL;
*rem = r;
}
return z;
}
return z;
}
break;
}