static T add(T z, T x, T y) {
int n = y->ndigits;
if (x->ndigits < n)
return add(z, y, x);
else if (x->ndigits > n) {
int carry = XP_add(n, z->digits, x->digits,
y->digits, 0);
z->digits[z->size-1] = XP_sum(x->ndigits - n,
&z->digits[n], &x->digits[n], carry);
} else
z->digits[n] = XP_add(n, z->digits, x->digits,
y->digits, 0);
return normalize(z, z->size);
}
T MP_addu(T z, T x, T y) {
int carry;
assert(x); assert(y); assert(z);
carry = XP_add(nbytes, z, x, y, 0);
carry |= z[nbytes-1]&~msb;
z[nbytes-1] &= msb;
if (carry)
RAISE(MP_Overflow);
return z;
}
T MP_add(T z, T x, T y) {
int sx, sy;
assert(x); assert(y); assert(z);
sx = sign(x);
sy = sign(y);
XP_add(nbytes, z, x, y, 0);
z[nbytes-1] &= msb;
if (sx == sy && sy != sign(z))
RAISE(MP_Overflow);
return z;
}
