Subversion Repositories openrisc

// 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
}