T MP_mul(T z, T x, T y) {
int sx, sy;
assert(x); assert(y); assert(z);
sx = sign(x);
sy = sign(y);
if (sx) {
XP_neg(nbytes, tmp[0], x, 1);
x = tmp[0];
x[nbytes-1] &= msb;
}
if (sy) {
XP_neg(nbytes, tmp[1], y, 1);
y = tmp[1];
y[nbytes-1] &= msb;
}
memset(tmp[3], '\0', 2*nbytes);
XP_mul(tmp[3], nbytes, x, nbytes, y);
if (sx != sy)
XP_neg(nbytes, z, tmp[3], 1);
else
memcpy(z, tmp[3], nbytes);
z[nbytes-1] &= msb;
{
int i;
if (tmp[3][nbytes-1]&~msb)
RAISE(MP_Overflow);
for (i = 0; i < nbytes; i++)
if (tmp[3][i+nbytes] != 0)
RAISE(MP_Overflow);
}
if (sx == sy && sign(z))
RAISE(MP_Overflow);
return z;
}
T MP_mul2u(T z, T x, T y) {
assert(x); assert(y); assert(z);
memset(tmp[3], '\0', 2*nbytes);
XP_mul(tmp[3], nbytes, x, nbytes, y);
memcpy(z, tmp[3], (2*nbits - 1)/8 + 1);
return z;
}
T AP_mul(T x, T y) {
T z;
assert(x);
assert(y);
z = mk(x->ndigits + y->ndigits);
XP_mul(z->digits, x->ndigits, x->digits, y->ndigits,
y->digits);
normalize(z, z->size);
z->sign = iszero(z)
|| ((x->sign^y->sign) == 0) ? 1 : -1;
return z;
}
T MP_mulu(T z, T x, T y) {
assert(x); assert(y); assert(z);
memset(tmp[3], '\0', 2*nbytes);
XP_mul(tmp[3], nbytes, x, nbytes, y);
memcpy(z, tmp[3], nbytes);
z[nbytes-1] &= msb;
{
int i;
if (tmp[3][nbytes-1]&~msb)
RAISE(MP_Overflow);
for (i = 0; i < nbytes; i++)
if (tmp[3][i+nbytes] != 0)
RAISE(MP_Overflow);
}
return z;
}
T MP_mul2(T z, T x, T y) {
int sx, sy;
assert(x); assert(y); assert(z);
sx = sign(x);
sy = sign(y);
if (sx) {
XP_neg(nbytes, tmp[0], x, 1);
x = tmp[0];
x[nbytes-1] &= msb;
}
if (sy) {
XP_neg(nbytes, tmp[1], y, 1);
y = tmp[1];
y[nbytes-1] &= msb;
}
memset(tmp[3], '\0', 2*nbytes);
XP_mul(tmp[3], nbytes, x, nbytes, y);
if (sx != sy)
XP_neg((2*nbits - 1)/8 + 1, z, tmp[3], 1);
else
memcpy(z, tmp[3], (2*nbits - 1)/8 + 1);
return z;
}
