S0

#define S0	(		k,
			st )

Value:

        { LOAD(k);                                                   \
        b0  = (int64_t)vz[0]*w1 + (int64_t)vy[0]*w0;                           \
        a0  = (int64_t)vz[0]*w0 - (int64_t)vy[0]*w1;                           \
        if (st == 1) {                                                         \
        b1  = (int64_t)vz[1]*w1 + (int64_t)vy[1]*w0;                           \
        a1  = (int64_t)vz[1]*w0 - (int64_t)vy[1]*w1; } }