gcc/libgo/go/math/nextafter.go
Ian Lance Taylor f8d9fa9e80 libgo, compiler: Upgrade libgo to Go 1.4, except for runtime.
This upgrades all of libgo other than the runtime package to
the Go 1.4 release.  In Go 1.4 much of the runtime was
rewritten into Go.  Merging that code will take more time and
will not change the API, so I'm putting it off for now.

There are a few runtime changes anyhow, to accomodate other
packages that rely on minor modifications to the runtime
support.

The compiler changes slightly to add a one-bit flag to each
type descriptor kind that is stored directly in an interface,
which for gccgo is currently only pointer types.  Another
one-bit flag (gcprog) is reserved because it is used by the gc
compiler, but gccgo does not currently use it.

There is another error check in the compiler since I ran
across it during testing.

gotools/:
	* Makefile.am (go_cmd_go_files): Sort entries.  Add generate.go.
	* Makefile.in: Rebuild.

From-SVN: r219627
2015-01-15 00:27:56 +00:00

48 lines
1.2 KiB
Go

// 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
// Nextafter32 returns the next representable float32 value after x towards y.
// Special cases:
// Nextafter32(x, x) = x
// Nextafter32(NaN, y) = NaN
// Nextafter32(x, NaN) = NaN
func Nextafter32(x, y float32) (r float32) {
switch {
case IsNaN(float64(x)) || IsNaN(float64(y)): // special case
r = float32(NaN())
case x == y:
r = x
case x == 0:
r = float32(Copysign(float64(Float32frombits(1)), float64(y)))
case (y > x) == (x > 0):
r = Float32frombits(Float32bits(x) + 1)
default:
r = Float32frombits(Float32bits(x) - 1)
}
return
}
// Nextafter returns the next representable float64 value after x towards y.
// Special cases:
// Nextafter64(x, x) = x
// Nextafter64(NaN, y) = NaN
// Nextafter64(x, NaN) = NaN
func Nextafter(x, y float64) (r float64) {
switch {
case IsNaN(x) || IsNaN(y): // special case
r = NaN()
case x == y:
r = x
case x == 0:
r = Copysign(Float64frombits(1), y)
case (y > x) == (x > 0):
r = Float64frombits(Float64bits(x) + 1)
default:
r = Float64frombits(Float64bits(x) - 1)
}
return
}