fpu_neg2wc
c = fpu_neg2wc(&z[3], z[3], c);
c = fpu_neg2wc(&z[2], z[2], c);
c = fpu_neg2wc(&z[1], z[1], c);
c = fpu_neg2wc(&z[0], z[0], c);
extern uint_t fpu_neg2wc(uint_t *, uint_t, uint_t);