`11210 libm should be cstyle(1ONBLD) clean`

```   1 /*
3  *
4  * The contents of this file are subject to the terms of the
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
18  *
20  */
21
22 /*
24  */
25
26 /*
28  * Use is subject to license terms.
29  */
30
31 #pragma weak __acos = acos
32
33
34 /*
35  * acos(x)
36  * Method :
37  *      acos(x)  = pi/2 - asin(x)
38  *      acos(-x) = pi/2 + asin(x)
39  * For |x|<=0.5
40  *      acos(x) = pi/2 - (x + x*x^2*R(x^2))     (see asin.c)
41  * For x>0.5
42  *      acos(x) = pi/2 - (pi/2 - 2asin(sqrt((1-x)/2)))
43  *              = 2asin(sqrt((1-x)/2))
44  *              = 2s + 2s*z*R(z)        ...z=(1-x)/2, s=sqrt(z)
45  *              = 2f + (2c + 2s*z*R(z))
46  *     where f=hi part of s, and c = (z-f*f)/(s+f) is the correction term
47  *     for f so that f+c ~ sqrt(z).
48  * For x<-0.5
49  *      acos(x) = pi - 2asin(sqrt((1-|x|)/2))
50  *              = pi - 0.5*(s+s*z*R(z)), where z=(1-|x|)/2,s=sqrt(z)
51  *
52  * Special cases:
53  *      if x is NaN, return x itself;
54  *      if |x|>1, return NaN with invalid signal.
55  *
56  * Function needed: sqrt
57  */

58
59 #include "libm_protos.h"                /* _SVID_libm_error */
60 #include "libm_macros.h"
61 #include <math.h>
62

63 static const double xxx[] = {
64 /* one */
65         1.00000000000000000000e+00,             /* 3FF00000, 00000000 */
66 /* pi */ 3.14159265358979311600e+00,            /* 400921FB, 54442D18 */
67 /* pio2_hi */ 1.57079632679489655800e+00,       /* 3FF921FB, 54442D18 */
68 /* pio2_lo */ 6.12323399573676603587e-17,       /* 3C91A626, 33145C07 */
69 /* pS0 */ 1.66666666666666657415e-01,           /* 3FC55555, 55555555 */
70 /* pS1 */ -3.25565818622400915405e-01,          /* BFD4D612, 03EB6F7D */
71 /* pS2 */ 2.01212532134862925881e-01,           /* 3FC9C155, 0E884455 */
72 /* pS3 */ -4.00555345006794114027e-02,          /* BFA48228, B5688F3B */
73 /* pS4 */ 7.91534994289814532176e-04,           /* 3F49EFE0, 7501B288 */
74 /* pS5 */ 3.47933107596021167570e-05,           /* 3F023DE1, 0DFDF709 */
75 /* qS1 */ -2.40339491173441421878e+00,          /* C0033A27, 1C8A2D4B */
76 /* qS2 */ 2.02094576023350569471e+00,           /* 40002AE5, 9C598AC8 */
77 /* qS3 */ -6.88283971605453293030e-01,          /* BFE6066C, 1B8D0159 */
78 /* qS4 */ 7.70381505559019352791e-02            /* 3FB3B8C5, B12E9282 */
79 };
80
81 #define one             xxx[0]
82 #define pi              xxx[1]
83 #define pio2_hi         xxx[2]
84 #define pio2_lo         xxx[3]
85 #define pS0             xxx[4]
86 #define pS1             xxx[5]
87 #define pS2             xxx[6]
88 #define pS3             xxx[7]
89 #define pS4             xxx[8]
90 #define pS5             xxx[9]
91 #define qS1             xxx[10]
92 #define qS2             xxx[11]
93 #define qS3             xxx[12]
94 #define qS4             xxx[13]

95
96 double
97 acos(double x)
98 {
99         double z, p, q, r, w, s, c, df;
100         int hx, ix;
101
102         hx = ((int *)&x)[HIWORD];
103         ix = hx & 0x7fffffff;
104
105         if (ix >= 0x3ff00000) {              /* |x| >= 1 */
106                 if (((ix - 0x3ff00000) | ((int *)&x)[LOWORD]) == 0) {
107                         /* |x| == 1 */
108                         if (hx > 0)  /* acos(1) = 0 */
109                                 return (0.0);
110                         else            /* acos(-1) = pi */
111                                 return (pi + 2.0 * pio2_lo);
112                 } else if (isnan(x)) {
114                         return (ix >= 0x7ff80000 ? x : (x - x) / (x - x));
115                 /* assumes sparc-like QNaN */
116 #else
117                         return ((x - x) / (x - x));     /* acos(|x|>1) is NaN */
118 #endif
119                 } else {
120                         return (_SVID_libm_err(x, x, 1));
121                 }
122         }
123
124         if (ix < 0x3fe00000) {                               /* |x| < 0.5 */
125                 if (ix <= 0x3c600000)
126                         return (pio2_hi + pio2_lo);     /* if |x| < 2**-57 */
127
128                 z = x * x;
129                 p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z *
130                     pS5)))));
131                 q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
132                 r = p / q;
133                 return (pio2_hi - (x - (pio2_lo - x * r)));
134         } else if (hx < 0) {
135                 /* x < -0.5 */
136                 z = (one + x) * 0.5;
137                 p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z *
138                     pS5)))));
139                 q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
140                 s = sqrt(z);
141                 r = p / q;
142                 w = r * s - pio2_lo;
143                 return (pi - 2.0 * (s + w));
144         } else {
145                 /* x > 0.5 */
146                 z = (one - x) * 0.5;
147                 s = sqrt(z);
148                 df = s;
149                 ((int *)&df)[LOWORD] = 0;
150                 c = (z - df * df) / (s + df);
151                 p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z *
152                     pS5)))));
153                 q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
154                 r = p / q;
155                 w = r * s + c;
156                 return (2.0 * (df + w));
157         }
158 }
--- EOF ---

```