57 lines
2.1 KiB
ArmAsm
57 lines
2.1 KiB
ArmAsm
/*
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* Copyright (c) 1993,94 Winning Strategies, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Winning Strategies, Inc.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Written by:
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* J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
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*/
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#include <machine/asm.h>
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RCSID("$FreeBSD$")
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/*
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* acos(x) = atan2(sqrt(1 - x^2, x).
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* Actually evaluate (1 - x^2) as (1 - x) * (1 + x) to avoid loss of
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* precision when |x| is nearly 1.
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*/
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ENTRY(__ieee754_acos)
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fldl 4(%esp) /* x */
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fld1
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fld %st(0)
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fsub %st(2) /* 1 - x */
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fxch %st(1)
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fadd %st(2) /* 1 + x */
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fmulp %st(1) /* (1 - x) * (1 + x) */
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fsqrt
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fxch %st(1)
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fpatan
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ret
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