x.validate()
	}
	if x.form == finite {
		exp = int(x.exp)
	}
	if mant != nil {
		mant.Copy(x)
		if mant.form == finite {
			mant.exp = 0
		}
	}
	return
}

func (z *Float) setExpAndRound(exp int64, sbit uint) {
	if exp < MinExp {
		// underflow
		z.acc = makeAcc(z.neg)
		z.form = zero
		return
	}

	if exp > MaxExp {
		// overflow
		z.acc = makeAcc(!z.neg)
		z.form = inf