// 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):

	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 {

	// riscv64:"FSGNJD"
	// arm64:"ORR", -"AND"
	sink64[1] = math.Copysign(c, -1)

	// Like math.Copysign(c, -1), but with integer operations. Useful
	// for platforms that have a copysign opcode to see if it's detected.
	// s390x:"LNDFR\t",-"MOVD\t"     (no integer load/store)
	sink64[2] = math.Float64frombits(math.Float64bits(a) | 1<<63)

	// amd64:"ANDQ","ORQ"
	// s390x:"CPSDR\t",-"MOVD\t"     (no integer load/store)

		err(t, "cmp(%g, %g) = sw %v, %v, hw %v, %v\n", f, g, scmp, sisnan, hcmp, hisnan)
	}
}

func same(f, g float64) bool {
	if math.IsNaN(f) && math.IsNaN(g) {
		return true
	}
	if math.Copysign(1, f) != math.Copysign(1, g) {
		return false
	}
	return f == g