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comparison src/build-msvctools/math/acoshf.c @ 3061:f8299bb6c872

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Initial support for native MSVC compilation. * add MSVC support files: compiler wrappers and support libraries * adapt libiconv to work with MSVC * adapt gettext to work with MSVC
author Michael Goffioul <michael.goffioul@gmail.com>
date Mon, 17 Jun 2013 22:43:11 -0400
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3060:cbdf4575016d 3061:f8299bb6c872
1 #include <math.h>
2 #include <errno.h>
3 #include "fastmath.h"
4
5 /* acosh(x) = log (x + sqrt(x * x - 1)) */
6 float acoshf (float x)
7 {
8 if (isnan (x))
9 return x;
10 if (x < 1.0f)
11 {
12 errno = EDOM;
13 return nan("");
14 }
15
16 if (x > 0x1p32f)
17 /* Avoid overflow (and unnecessary calculation when
18 sqrt (x * x - 1) == x). GCC optimizes by replacing
19 the long double M_LN2 const with a fldln2 insn. */
20 return __fast_log (x) + 6.9314718055994530941723E-1L;
21
22 /* Since x >= 1, the arg to log will always be greater than
23 the fyl2xp1 limit (approx 0.29) so just use logl. */
24 return __fast_log (x + __fast_sqrt((x + 1.0) * (x - 1.0)));
25 }