xref: /freebsd/lib/msun/src/s_sinpif.c (revision 716fd348e01c5f2ba125f878a634a753436c2994)
1 /*-
2  * Copyright (c) 2017 Steven G. Kargl
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 /*
28  * See ../src/s_sinpi.c for implementation details.
29  */
30 
31 #define	INLINE_KERNEL_SINDF
32 #define	INLINE_KERNEL_COSDF
33 
34 #include "math.h"
35 #include "math_private.h"
36 #include "k_cosf.c"
37 #include "k_sinf.c"
38 
39 #define	__kernel_cospif(x)	(__kernel_cosdf(M_PI * (x)))
40 #define	__kernel_sinpif(x)	(__kernel_sindf(M_PI * (x)))
41 
42 static const float
43 pi_hi =  3.14160156e+00F,	/* 0x40491000 */
44 pi_lo = -8.90890988e-06F;	/* 0xb715777a */
45 
46 volatile static const float vzero = 0;
47 
48 float
49 sinpif(float x)
50 {
51 	float ax, hi, lo, s;
52 	uint32_t hx, ix, j0;
53 
54 	GET_FLOAT_WORD(hx, x);
55 	ix = hx & 0x7fffffff;
56 	SET_FLOAT_WORD(ax, ix);
57 
58 	if (ix < 0x3f800000) {			/* |x| < 1 */
59 		if (ix < 0x3e800000) {		/* |x| < 0.25 */
60 	 		if (ix < 0x38800000) {	/* |x| < 0x1p-14 */
61 				if (x == 0)
62 					return (x);
63 				SET_FLOAT_WORD(hi, hx & 0xffff0000);
64 				hi *= 0x1p23F;
65 				lo = x * 0x1p23F - hi;
66 				s = (pi_lo + pi_hi) * lo + pi_lo * hi +
67 				    pi_hi * hi;
68 				return (s * 0x1p-23F);
69 			}
70 
71 			s = __kernel_sinpif(ax);
72 			return ((hx & 0x80000000) ? -s : s);
73 		}
74 
75 		if (ix < 0x3f000000)		/* |x| < 0.5 */
76 			s = __kernel_cospif(0.5F - ax);
77 		else if (ix < 0x3f400000)	/* |x| < 0.75 */
78 			s = __kernel_cospif(ax - 0.5F);
79 		else
80 			s = __kernel_sinpif(1 - ax);
81 		return ((hx & 0x80000000) ? -s : s);
82 	}
83 
84 	if (ix < 0x4b000000) {			/* 1 <= |x| < 0x1p23 */
85 		/* Determine integer part of ax. */
86 		j0 = ((ix >> 23) & 0xff) - 0x7f;
87 		ix &= ~(0x007fffff >> j0);
88 		SET_FLOAT_WORD(x, ix);
89 
90 		ax -= x;
91 		GET_FLOAT_WORD(ix, ax);
92 
93 		if (ix == 0)
94 			s = 0;
95 		else {
96 			if (ix < 0x3f000000) {		/* |x| < 0.5 */
97 				if (ix < 0x3e800000)	/* |x| < 0.25 */
98 					s = __kernel_sinpif(ax);
99 				else
100 					s = __kernel_cospif(0.5F - ax);
101 			} else {
102 				if (ix < 0x3f400000)	/* |x| < 0.75 */
103 					s = __kernel_cospif(ax - 0.5F);
104 				else
105 					s = __kernel_sinpif(1 - ax);
106 			}
107 
108 			j0 = (uint32_t)x;
109 			s = (j0 & 1) ? -s : s;
110 		}
111 		return ((hx & 0x80000000) ? -s : s);
112 	}
113 
114 	/* x = +-inf or nan. */
115 	if (ix >= 0x7f800000)
116 		return (vzero / vzero);
117 
118 	/*
119 	 * |x| >= 0x1p23 is always an integer, so return +-0.
120 	 */
121 	return (copysignf(0, x));
122 }
123