gcc/libgo/go/math/sinh.go
Ian Lance Taylor 7a9389330e Add Go frontend, libgo library, and Go testsuite.
gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.

From-SVN: r167407
2010-12-03 04:34:57 +00:00

69 lines
1.3 KiB
Go

// Copyright 2009 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 hyperbolic sine and cosine.
The exponential func is called for arguments
greater in magnitude than 0.5.
A series is used for arguments smaller in magnitude than 0.5.
Cosh(x) is computed from the exponential func for
all arguments.
*/
// Sinh returns the hyperbolic sine of x.
func Sinh(x float64) float64 {
// The coefficients are #2029 from Hart & Cheney. (20.36D)
const (
P0 = -0.6307673640497716991184787251e+6
P1 = -0.8991272022039509355398013511e+5
P2 = -0.2894211355989563807284660366e+4
P3 = -0.2630563213397497062819489e+2
Q0 = -0.6307673640497716991212077277e+6
Q1 = 0.1521517378790019070696485176e+5
Q2 = -0.173678953558233699533450911e+3
)
sign := false
if x < 0 {
x = -x
sign = true
}
var temp float64
switch true {
case x > 21:
temp = Exp(x) / 2
case x > 0.5:
temp = (Exp(x) - Exp(-x)) / 2
default:
sq := x * x
temp = (((P3*sq+P2)*sq+P1)*sq + P0) * x
temp = temp / (((sq+Q2)*sq+Q1)*sq + Q0)
}
if sign {
temp = -temp
}
return temp
}
// Cosh returns the hyperbolic cosine of x.
func Cosh(x float64) float64 {
if x < 0 {
x = -x
}
if x > 21 {
return Exp(x) / 2
}
return (Exp(x) + Exp(-x)) / 2
}