{Inf(-1), NaN()},
	{-Pi, Inf(-1)},
	{-Pi, 0},
	{-Pi, Inf(1)},
	{-Pi, NaN()},
	{Copysign(0, -1), Inf(-1)},
	{Copysign(0, -1), -Pi},
	{Copysign(0, -1), Copysign(0, -1)},
	{Copysign(0, -1), 0},
	{Copysign(0, -1), +Pi},
	{Copysign(0, -1), Inf(1)},
	{Copysign(0, -1), NaN()},
	{0, Inf(-1)},
	{0, -Pi},
	{0, Copysign(0, -1)},
	{0, 0},
	{0, +Pi},
	{0, Inf(1)},
	{0, NaN()},
	{+Pi, Inf(-1)},

// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package math

// Copysign returns a value with the magnitude of f
// and the sign of sign.
func Copysign(f, sign float64) float64 {
	const signBit = 1 << 63
	return Float64frombits(Float64bits(f)&^signBit | Float64bits(sign)&signBit)

		if x >= 0 && !Signbit(x) {
			return Copysign(0, y)
		}
		return Copysign(Pi, y)
	case x == 0:
		return Copysign(Pi/2, y)
	case IsInf(x, 0):
		if IsInf(x, 1) {
			switch {
			case IsInf(y, 0):
				return Copysign(Pi/4, y)
			default:
				return Copysign(0, y)
			}
		}
		switch {
		case IsInf(y, 0):
			return Copysign(3*Pi/4, y)
		default:
			return Copysign(Pi, y)
		}
	case IsInf(y, 0):

	}
	if math.Copysign(math.NaN(), -1) < math.NaN() {
		t.Errorf("math.Copysign(math.NaN(), -1) < math.NaN() returned true")
	}
	if math.Inf(1) != math.Inf(1) {
		t.Errorf("math.Inf(1) != math.Inf(1) returned true")
	}
	if math.Inf(-1) != math.Inf(-1) {
		t.Errorf("math.Inf(-1) != math.Inf(-1) returned true")
	}
	if math.Copysign(0, -1) != 0 {
		t.Errorf("math.Copysign(0, -1) != 0 returned true")
	}

	n int32
}

func F1(f float64) *S {
	s := f
	pf := math.Copysign(f, 1)
	u := math.Floor(pf)
	return &S{
		u: int64(math.Copysign(u, s)),
		n: int32(math.Copysign((pf-u)*1e9, s)),
	}
}

func F2(f float64) *S {
	s := f
	f = math.Copysign(f, 1)
	u := math.Floor(f)
	return &S{
		u: int64(math.Copysign(u, s)),
		n: int32(math.Copysign((f-u)*1e9, s)),
	}
}

func main() {
	s1 := F1(-1)

		}
	case math.IsInf(im, 0):
		switch {
		case math.IsNaN(re):
			return x
		case math.IsInf(re, 0):
			return complex(math.Copysign(math.Pi/4, re), im)
		default:
			return complex(math.Copysign(0, re), im)
		}
	case math.IsInf(re, 0):
		return complex(math.Copysign(math.Pi/2, re), math.Copysign(re, im))
	}
	ct := complex(-imag(x), real(x)) // i * x
	xx := x * x
	x1 := complex(1-real(xx), -imag(xx)) // 1 - x*x

		// Matches C99: ISO/IEC 9899:1999 - G.5.1  Multiplicative operators.

		a, b := real(n), imag(n)
		c, d := real(m), imag(m)

		switch {
		case m == 0 && (!isNaN(a) || !isNaN(b)):
			e = copysign(inf, c) * a
			f = copysign(inf, c) * b

		case (isInf(a) || isInf(b)) && isFinite(c) && isFinite(d):
			a = inf2one(a)
			b = inf2one(b)
			e = inf * (a*c + b*d)
			f = inf * (b*c - a*d)

	switch re, im := real(x), imag(x); {
	case math.IsInf(im, 0):
		switch {
		case math.IsInf(re, 0) || math.IsNaN(re):
			return complex(math.Copysign(0, re), math.Copysign(1, im))
		}
		return complex(math.Copysign(0, math.Sin(2*re)), math.Copysign(1, im))
	case re == 0 && math.IsNaN(im):
		return x
	}
	d := math.Cos(2*real(x)) + math.Cosh(2*imag(x))
	if math.Abs(d) < 0.25 {
		d = tanSeries(x)
	}

func Cos(x complex128) complex128 {
	switch re, im := real(x), imag(x); {
	case im == 0 && (math.IsInf(re, 0) || math.IsNaN(re)):
		return complex(math.NaN(), -im*math.Copysign(0, re))
	case math.IsInf(im, 0):
		switch {
		case re == 0:
			return complex(math.Inf(1), -re*math.Copysign(0, im))
		case math.IsInf(re, 0) || math.IsNaN(re):
			return complex(math.Inf(1), math.NaN())
		}
	case re == 0 && math.IsNaN(im):

//	Round(NaN) = NaN
func Round(x float64) float64 {
	// Round is a faster implementation of:
	//
	// func Round(x float64) float64 {
	//   t := Trunc(x)
	//   if Abs(x-t) >= 0.5 {
	//     return t + Copysign(1, x)
	//   }
	//   return t
	// }
	bits := Float64bits(x)
	e := uint(bits>>shift) & mask
	if e < bias {
		// Round abs(x) < 1 including denormals.
		bits &= signMask // +-0
		if e == bias-1 {