freebsd-nq/lib/msun/i387/e_acos.S
David Schultz e1b61b5b93 Remove wrappers and other cruft intended to support SVID, mistakes in
C90, and other arcana.  Most of these features were never fully
supported or enabled by default.

Ok:	bde, stefanf
2005-02-04 14:08:32 +00:00

57 lines
2.1 KiB
ArmAsm

/*
* Copyright (c) 1993,94 Winning Strategies, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Winning Strategies, Inc.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Written by:
* J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
*/
#include <machine/asm.h>
RCSID("$FreeBSD$")
/*
* acos(x) = atan2(sqrt(1 - x^2, x).
* Actually evaluate (1 - x^2) as (1 - x) * (1 + x) to avoid loss of
* precision when |x| is nearly 1.
*/
ENTRY(acos)
fldl 4(%esp) /* x */
fld1
fld %st(0)
fsub %st(2) /* 1 - x */
fxch %st(1)
fadd %st(2) /* 1 + x */
fmulp %st(1) /* (1 - x) * (1 + x) */
fsqrt
fxch %st(1)
fpatan
ret