libm: Add .section .note.GNU-stack to all assembly files
[dragonfly.git] / lib / libm / arch / i386 / e_exp.S
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1/* $NetBSD: e_exp.S,v 1.14 2008/06/23 10:24:13 drochner Exp $ */
2
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3/*
4 * Copyright (c) 1993,94 Winning Strategies, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by Winning Strategies, Inc.
18 * 4. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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31 */
32
33/*
34 * Written by:
35 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
36 */
37
38#include <machine/asm.h>
39
40#include "abi.h"
41
42
43/* e^x = 2^(x * log2(e)) */
44ENTRY(exp)
74dfd0cf 45 XMM_ONE_ARG_DOUBLE_PROLOGUE
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46 /*
47 * If x is +-Inf, then the subtraction would give Inf-Inf = NaN.
48 * Avoid this. Also avoid it if x is NaN for convenience.
49 */
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50 movl ARG_DOUBLE_ONE_MSW, %eax
51 andl $0x7fffffff, %eax
52 cmpl $0x7ff00000, %eax
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53 jae x_Inf_or_NaN
54
74dfd0cf 55 fldl ARG_DOUBLE_ONE
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56
57 /*
58 * Ensure that the rounding mode is to nearest (to give the smallest
59 * possible fraction) and that the precision is as high as possible.
60 * We may as well mask interrupts if we switch the mode.
61 */
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62#define CWSTORE_SAV ARG_DOUBLE_ONE_LSW /* XXX overwrites the argument */
63#define CWSTORE_TMP ARG_DOUBLE_ONE_MSW
64 fstcw CWSTORE_SAV
65 movl CWSTORE_SAV, %eax
66 andl $0x0f00, %eax
67 cmpl $0x0300, %eax /* RC == 0 && PC == 3? */
b34b60bc 68 je 1f /* jump if mode is good */
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69 movl $0x137f, CWSTORE_TMP
70 fldcw CWSTORE_TMP
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711:
72 fldl2e
73 fmulp /* x * log2(e) */
74 fst %st(1)
75 frndint /* int(x * log2(e)) */
76 fst %st(2)
77 fsubrp /* fract(x * log2(e)) */
78 f2xm1 /* 2^(fract(x * log2(e))) - 1 */
79 fld1
80 faddp /* 2^(fract(x * log2(e))) */
81 fscale /* e^x */
82 fstp %st(1)
83 je 1f
74dfd0cf 84 fldcw CWSTORE_SAV
b34b60bc 851:
74dfd0cf 86 XMM_DOUBLE_EPILOGUE
b34b60bc 87 ret
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88x_Inf_or_NaN:
89 /*
90 * Return 0 if x is -Inf. Otherwise just return x, although the
91 * C version would return (x + x) (Real Indefinite) if x is a NaN.
92 */
74dfd0cf 93 cmpl $0xfff00000, ARG_DOUBLE_ONE_MSW
b34b60bc 94 jne x_not_minus_Inf
74dfd0cf 95 cmpl $0, ARG_DOUBLE_ONE_LSW
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96 jne x_not_minus_Inf
97 fldz
74dfd0cf 98 XMM_DOUBLE_EPILOGUE
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99 ret
100
101x_not_minus_Inf:
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102 fldl ARG_DOUBLE_ONE
103 XMM_DOUBLE_EPILOGUE
b34b60bc 104 ret
d04e8698 105END(exp)
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106
107 .section .note.GNU-stack,"",%progbits