1 /*-
2  * ====================================================
3  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4  *
5  * Developed at SunPro, a Sun Microsystems, Inc. business.
6  * Permission to use, copy, modify, and distribute this
7  * software is freely granted, provided that this notice
8  * is preserved.
9  * ====================================================
10  */
11 
12 /* s_sincosf.c -- float version of s_sincos.c.
13  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
14  * Optimized by Bruce D. Evans.
15  * Merged s_sinf.c and s_cosf.c by Steven G. Kargl.
16  */
17 
18 #include <float.h>
19 #include "math.h"
20 
21 #include "math_private.h"
22 #include "k_sincosf.h"
23 
24 /* Small multiples of pi/2 rounded to double precision. */
25 static const double
26 p1pio2 = 1*M_PI_2,			/* 0x3FF921FB, 0x54442D18 */
27 p2pio2 = 2*M_PI_2,			/* 0x400921FB, 0x54442D18 */
28 p3pio2 = 3*M_PI_2,			/* 0x4012D97C, 0x7F3321D2 */
29 p4pio2 = 4*M_PI_2;			/* 0x401921FB, 0x54442D18 */
30 
31 void
32 sincosf(float x, float *sn, float *cs)
33 {
34 	float c, s;
35 	float y[2];
36 	int32_t n, hx, ix;
37 
38 	GET_FLOAT_WORD(hx, x);
39 	ix = hx & 0x7fffffff;
40 
41 	if (ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
42 		if (ix < 0x39800000) {	/* |x| < 2**-12 */
43 			if ((int)x == 0) {
44 				*sn = x;	/* x with inexact if x != 0 */
45 				*cs = 1;
46 				return;
47 			}
48 		}
49 		__kernel_sincosdf(x, sn, cs);
50 		return;
51 	}
52 
53 	if (ix <= 0x407b53d1) {		/* |x| ~<= 5*pi/4 */
54 		if (ix <= 0x4016cbe3) {	/* |x| ~<= 3pi/4 */
55 			if (hx > 0) {
56 				__kernel_sincosdf(x - p1pio2, cs, sn);
57 				*cs = -*cs;
58 			} else {
59 				__kernel_sincosdf(x + p1pio2, cs, sn);
60 				*sn = -*sn;
61 			}
62 		} else {
63 			if (hx > 0)
64 				__kernel_sincosdf(x - p2pio2, sn, cs);
65 			else
66 				__kernel_sincosdf(x + p2pio2, sn, cs);
67 			*sn = -*sn;
68 			*cs = -*cs;
69 		}
70 		return;
71 	}
72 
73 	if (ix <= 0x40e231d5) {		/* |x| ~<= 9*pi/4 */
74 		if (ix <= 0x40afeddf) {	/* |x| ~<= 7*pi/4 */
75 			if (hx > 0) {
76 				__kernel_sincosdf(x - p3pio2, cs, sn);
77 				*sn = -*sn;
78 			} else {
79 				__kernel_sincosdf(x + p3pio2, cs, sn);
80 				*cs = -*cs;
81 			}
82 		} else {
83 			if (hx > 0)
84 				__kernel_sincosdf(x - p4pio2, sn, cs);
85 			else
86 				__kernel_sincosdf(x + p4pio2, sn, cs);
87 		}
88 		return;
89 	}
90 
91 	/* If x = Inf or NaN, then sin(x) = NaN and cos(x) = NaN. */
92 	if (ix >= 0x7f800000) {
93 		*sn = x - x;
94 		*cs = x - x;
95 		return;
96 	}
97 
98 	/* Argument reduction. */
99 	n = __ieee754_rem_pio2f(x, y);
100 	s = __kernel_sinf(y[0], y[1], 1);
101 	c = __kernel_cosf(y[0], y[1]);
102 
103 	switch(n & 3) {
104 	case 0:
105 		*sn = s;
106 		*cs = c;
107 		break;
108 	case 1:
109 		*sn = c;
110 		*cs = -s;
111 		break;
112 	case 2:
113 		*sn = -s;
114 		*cs = -c;
115 		break;
116 	default:
117 		*sn = -c;
118 		*cs = s;
119 	}
120 }
121