union u_t {  long value;  __fixed16x16 fix;};__fixed16x16 __fps16x16_mul(__fixed16x16 a, __fixed16x16 b){  volatile union u_t u1, u2;  u1.fix = a;  u2.fix = b;    u1.value = (u1.value >> 4) * (u2.value >> 4) >> 8;    return (u1.fix);}