{"4p-2048", "2p-1024"},
		{"9p-4096", "3p-2048"},
	} {
		for _, prec := range []uint{24, 53, 64, 65, 100, 128, 129, 200, 256, 400, 600, 800, 1000} {
			x := new(Float).SetPrec(prec)
			x.Parse(test.x, 10)

			got := new(Float).SetPrec(prec).Sqrt(x)
			want := new(Float).SetPrec(prec)
			want.Parse(test.want, 10)
			if got.Cmp(want) != 0 {
				t.Errorf("prec = %d, Sqrt(%v) =\ngot  %g;\nwant %g",
					prec, test.x, got, want)
			}

	// Operate on numbers of different precision.
	var x, y, z big.Float
	x.SetInt64(1000)          // x is automatically set to 64bit precision
	y.SetFloat64(2.718281828) // y is automatically set to 53bit precision
	z.SetPrec(32)
	z.Add(&x, &y)
	fmt.Printf("x = %.10g (%s, prec = %d, acc = %s)\n", &x, x.Text('p', 0), x.Prec(), x.Acc())
	fmt.Printf("y = %.10g (%s, prec = %d, acc = %s)\n", &y, y.Text('p', 0), y.Prec(), y.Acc())

	for _, prec := range precList {
		two := new(Float).SetPrec(prec).SetInt64(2)
		one := new(Float).SetPrec(prec).SetInt64(1)
		three := new(Float).SetPrec(prec).SetInt64(3)
		msix := new(Float).SetPrec(prec).SetInt64(-6)
		psix := new(Float).SetPrec(prec).SetInt64(+6)

		p := new(Float).SetPrec(prec)
		z1 := new(Float).SetPrec(prec)
		z2 := new(Float).SetPrec(prec)

		// z1 = 2 + 1.0/3*-6
		p.Quo(one, three)

					x := sign + test

					var tx Float
					_, _, err := tx.SetPrec(prec).SetMode(mode).Parse(x, 0)
					if err != nil {
						t.Errorf("parsing of %s (%dbits, %v) failed (invalid test case): %v", x, prec, mode, err)
						continue
					}

					// If tx was set to prec == 0, tx.Parse(x, 0) assumes precision 64. Correct it.
					if prec == 0 {
						tx.SetPrec(0)
					}

					if err := enc.Encode(&tx); err != nil {

	steps := int(math.Log2(prec))

	// Initialize values we need for the computation.
	two := new(big.Float).SetPrec(prec).SetInt64(2)
	half := new(big.Float).SetPrec(prec).SetFloat64(0.5)

	// Use 1 as the initial estimate.
	x := new(big.Float).SetPrec(prec).SetInt64(1)

	// We use t as a temporary variable. There's no need to set its precision

			var d decimal
			d.init(natOne, shift)
			sink = d.String()
		}
	}
}

func BenchmarkFloatString(b *testing.B) {
	x := new(Float)
	for _, prec := range []uint{1e2, 1e3, 1e4, 1e5} {
		x.SetPrec(prec).SetRat(NewRat(1, 3))
		b.Run(fmt.Sprintf("%v", prec), func(b *testing.B) {
			b.ReportAllocs()
			for i := 0; i < b.N; i++ {
				sink = x.String()
			}
		})
	}

		err = fmt.Errorf("exponent overflow")
		return
	}

	if exp5 == 0 {
		// no decimal exponent contribution
		z.round(0)
		return
	}
	// exp5 != 0

	// apply 5**exp5
	p := new(Float).SetPrec(z.Prec() + 64) // use more bits for p -- TODO(gri) what is the right number?
	if exp5 < 0 {
		z.Quo(z, p.pow5(uint64(-exp5)))
	} else {
		z.Mul(z, p.pow5(uint64(exp5)))
	}

	return
}

		return fmt.Sprintf("%.6g", x)
	}

	return "OOPS"
}

func (x complexVal) String() string { return fmt.Sprintf("(%s + %si)", x.re, x.im) }

func newFloat() *big.Float { return new(big.Float).SetPrec(prec) }

//go:noinline
//go:registerparams
func itor(x intVal) ratVal       { return ratVal{nil} }

//go:noinline
//go:registerparams
func itof(x intVal) floatVal     { return floatVal{nil} }

		// erroneous formats
		{"%s", 1.0, "%!s(*big.Float=1)"},
	} {
		value := new(Float)
		switch v := test.value.(type) {
		case float32:
			value.SetPrec(24).SetFloat64(float64(v))
		case float64:
			value.SetPrec(53).SetFloat64(v)
		case string:
			value.SetPrec(512).Parse(v, 0)
		default:
			t.Fatalf("unsupported test value: %v (%T)", v, v)
		}

		if got := fmt.Sprintf(test.format, value); got != test.want {

			return errors.New("Float.GobDecode: buffer too small for finite form float")
		}
		z.exp = int32(byteorder.BeUint32(buf[6:]))
		z.mant = z.mant.setBytes(buf[10:])
	}

	if oldPrec != 0 {
		z.mode = oldMode
		z.SetPrec(uint(oldPrec))
	}

	if msg := z.validate0(); msg != "" {
		return errors.New("Float.GobDecode: " + msg)
	}

	return nil
}

// MarshalText implements the [encoding.TextMarshaler] interface.