1/*-
2 * Copyright (c) 2017,2023 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_cospi.c for implementation details.
29 */
30#define	INLINE_KERNEL_SINDF
31#define	INLINE_KERNEL_COSDF
32
33#include "math.h"
34#include "math_private.h"
35#include "k_cosf.c"
36#include "k_sinf.c"
37
38#define	__kernel_cospif(x)	(__kernel_cosdf(M_PI * (x)))
39#define	__kernel_sinpif(x)	(__kernel_sindf(M_PI * (x)))
40
41volatile static const float vzero = 0;
42
43float
44cospif(float x)
45{
46	float ax, c;
47	uint32_t ix, j0;
48
49	GET_FLOAT_WORD(ix, x);
50	ix = ix & 0x7fffffff;
51	SET_FLOAT_WORD(ax, ix);
52
53	if (ix < 0x3f800000) {			/* |x| < 1 */
54		if (ix < 0x3e800000) {		/* |x| < 0.25 */
55			if (ix < 0x38800000) {	/* |x| < 0x1p-14 */
56				/* Raise inexact iff != 0. */
57				if ((int)ax == 0)
58					return (1);
59			}
60			return (__kernel_cospif(ax));
61		}
62
63		if (ix < 0x3f000000)		/* |x| < 0.5 */
64			c = __kernel_sinpif(0.5F - ax);
65		else if (ix < 0x3f400000) {	/* |x| < 0.75 */
66			if (ix == 0x3f000000)
67				return (0);
68			c = -__kernel_sinpif(ax - 0.5F);
69		} else
70			c = -__kernel_cospif(1 - ax);
71		return (c);
72	}
73
74	if (ix < 0x4b000000) {		/* 1 <= |x| < 0x1p23 */
75		FFLOORF(x, j0, ix);	/* Integer part of ax. */
76		ax -= x;
77		GET_FLOAT_WORD(ix, ax);
78
79		if (ix < 0x3f000000) {		/* |x| < 0.5 */
80			if (ix < 0x3e800000)	/* |x| < 0.25 */
81				c = ix == 0 ? 1 : __kernel_cospif(ax);
82			else
83				c = __kernel_sinpif(0.5F - ax);
84		} else {
85			if (ix < 0x3f400000) {	/* |x| < 0.75 */
86				if (ix == 0x3f000000)
87					return (0);
88				c = -__kernel_sinpif(ax - 0.5F);
89			} else
90				c = -__kernel_cospif(1 - ax);
91		}
92
93		j0 = (uint32_t)x;
94		return (j0 & 1 ? -c : c);
95	}
96
97	/* x = +-inf or nan. */
98	if (ix >= 0x7f800000)
99		return (vzero / vzero);
100
101	/*
102	 * For 0x1p23 <= |x| < 0x1p24 need to determine if x is an even
103	 * or odd integer to return +1 or -1.
104	 * For |x| >= 0x1p24, it is always an even integer, so return 1.
105	 */
106	return (ix < 0x4b800000 ? ((ix & 1) ? -1 : 1) : 1);
107}
108