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// Copyright 2009-2010 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

/*

        Floating-point mod function.

*/

// Mod returns the floating-point remainder of x/y.

// The magnitude of the result is less than y and its

// sign agrees with that of x.

//

// Special cases are:

//      Mod(±Inf, y) = NaN

//      Mod(NaN, y) = NaN

//      Mod(x, 0) = NaN

//      Mod(x, ±Inf) = x

//      Mod(x, NaN) = NaN

//extern fmod

func libc_fmod(float64, float64) float64

func Mod(x, y float64) float64 {

        return libc_fmod(x, y)

}

func mod(x, y float64) float64 {

        if y == 0 || IsInf(x, 0) || IsNaN(x) || IsNaN(y) {

                return NaN()

        }

        if y < 0 {

                y = -y

        }

        yfr, yexp := Frexp(y)

        sign := false

        r := x

        if x < 0 {

                r = -x

                sign = true

        }

        for r >= y {

                rfr, rexp := Frexp(r)

                if rfr < yfr {

                        rexp = rexp - 1

                }

                r = r - Ldexp(y, rexp-yexp)

        }

        if sign {

                r = -r

        }

        return r

}