* Bring back rbuild build to be used until bug 6372 is fixed.
[reactos.git] / lib / sdk / crt / math / i386 / exp.c
1 /* Math functions for i387.
2 Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by John C. Bowman <bowman@ipp-garching.mpg.de>, 1995.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 Boston, MA 02110-1301, USA.
20 */
21
22 #include <math.h>
23
24 double exp (double __x);
25
26 double exp (double __x)
27 {
28 #ifdef __GNUC__
29 register double __value, __exponent;
30 __asm __volatile__
31 ("fldl2e # e^x = 2^(x * log2(e))\n\t"
32 "fmul %%st(1) # x * log2(e)\n\t"
33 "fst %%st(1)\n\t"
34 "frndint # int(x * log2(e))\n\t"
35 "fxch\n\t"
36 "fsub %%st(1) # fract(x * log2(e))\n\t"
37 "f2xm1 # 2^(fract(x * log2(e))) - 1\n\t"
38 : "=t" (__value), "=u" (__exponent) : "0" (__x));
39 __value += 1.0;
40 __asm __volatile__
41 ("fscale"
42 : "=t" (__value) : "0" (__value), "u" (__exponent));
43
44 return __value;
45 #else
46 register double __val;
47 __asm
48 {
49 fld1 // store 1.0 for later use
50 fld __x
51 fldl2e // e^x = 2^(x * log2(e))
52 fmul st,st(1) // x * log2(e)
53 fld st(0)
54 frndint // int(x * log2(e))
55 fsub st,st(1) // fract(x * log2(e))
56 fxch
57 f2xm1 // 2^(fract(x * log2(e))) - 1
58 fadd st,st(3) // + 1.0
59 fscale
60 fstp __val
61 }
62 return __val;
63 #endif /*__GNUC__*/
64 }