op         byte
	}{
		{ToZero, 3, -0x8, -0x1, -0x8, '+'},
		{AwayFromZero, 3, -0x8, -0x1, -0xa, '+'},
		{ToNegativeInf, 3, -0x8, -0x1, -0xa, '+'},

		{ToZero, 3, -0x8, 0x1, -0x8, '-'},
		{AwayFromZero, 3, -0x8, 0x1, -0xa, '-'},
		{ToNegativeInf, 3, -0x8, 0x1, -0xa, '-'},

		{ToZero, 3, -0x9, 0x1, -0x8, '*'},
		{AwayFromZero, 3, -0x9, 0x1, -0xa, '*'},
		{ToNegativeInf, 3, -0x9, 0x1, -0xa, '*'},

			f := new(big.Float).SetPrec(2).SetMode(mode).SetFloat64(f64)
			fmt.Printf("  %*g", len(mode.String()), f)
		}
		fmt.Println()
	}

	// Output:
	//    x  ToNearestEven  ToNearestAway  ToZero  AwayFromZero  ToNegativeInf  ToPositiveInf
	//  2.6              3              3       2             3              2              3
	//  2.5              2              3       2             3              2              3

	}

	// round
	f := z.Float() // rounded to zero
	if mode == ToNearestAway {
		panic("not yet implemented")
	}
	if mode == ToNearestEven && rbit == 1 && (sbit == 1 || sbit == 0 && bit0 != 0) || mode == AwayFromZero {
		// round away from zero
		f.SetMode(ToZero).SetPrec(prec)
		f.Add(f, Bits{int(r) + 1}.Float())
	}
	return f
}

// Float returns the *Float z of the smallest possible precision such that

const (
	ToNearestEven RoundingMode = iota // == IEEE 754-2008 roundTiesToEven
	ToNearestAway                     // == IEEE 754-2008 roundTiesToAway
	ToZero                            // == IEEE 754-2008 roundTowardZero
	AwayFromZero                      // no IEEE 754-2008 equivalent
	ToNegativeInf                     // == IEEE 754-2008 roundTowardNegative
	ToPositiveInf                     // == IEEE 754-2008 roundTowardPositive
)

			// try rounding down a little
			t.SetMode(big.ToZero)
			t.Set(x.val)
			if _, acc := t.Int(i); acc == big.Exact {
				return makeInt(i)
			}

			// try rounding up a little
			t.SetMode(big.AwayFromZero)
			t.Set(x.val)
			if _, acc := t.Int(i); acc == big.Exact {
				return makeInt(i)
			}
		}

	case complexVal:
		if re := ToFloat(x); re.Kind() == Float {
			return ToInt(re)
		}
	}

		{"(*Rat).UnmarshalText", Method, 3},
		{"(Accuracy).String", Method, 5},
		{"(ErrNaN).Error", Method, 5},
		{"(RoundingMode).String", Method, 5},
		{"Above", Const, 5},
		{"Accuracy", Type, 5},
		{"AwayFromZero", Const, 5},
		{"Below", Const, 5},
		{"ErrNaN", Type, 5},
		{"Exact", Const, 5},
		{"Float", Type, 5},
		{"Int", Type, 0},
		{"Jacobi", Func, 5},
		{"MaxBase", Const, 0},