INT_PI
(compat_remainder(carrier + tone, srate)) / srate * 2 * INT_PI))
u16 period = x / INT_PI;
return -int_cos(x - INT_PI);
x = x % INT_PI;
if (x > INT_PI / 2)
return -int_cos(INT_PI / 2 - (x % (INT_PI / 2)));