tf_fprl
s->tf_fppt, s->tf_fprh, s->tf_fprl, s->tf_fpit);
mant32 |= frame->tf_fprl >> (DBL_FRACBITS - SNG_FRACBITS);
mant64 |= frame->tf_fprl;
f->tf_fppt, f->tf_fprh, f->tf_fprl, f->tf_fpit);