xref: /freebsd/lib/msun/src/s_sincosf.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
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 <sys/cdefs.h>
19 #include <float.h>
20 
21 #include "math.h"
22 #define INLINE_REM_PIO2F
23 #include "math_private.h"
24 #include "e_rem_pio2f.c"
25 #include "k_sincosf.h"
26 
27 /* Small multiples of pi/2 rounded to double precision. */
28 static const double
29 p1pio2 = 1*M_PI_2,			/* 0x3FF921FB, 0x54442D18 */
30 p2pio2 = 2*M_PI_2,			/* 0x400921FB, 0x54442D18 */
31 p3pio2 = 3*M_PI_2,			/* 0x4012D97C, 0x7F3321D2 */
32 p4pio2 = 4*M_PI_2;			/* 0x401921FB, 0x54442D18 */
33 
34 void
35 sincosf(float x, float *sn, float *cs)
36 {
37 	float c, s;
38 	double y;
39 	int32_t n, hx, ix;
40 
41 	GET_FLOAT_WORD(hx, x);
42 	ix = hx & 0x7fffffff;
43 
44 	if (ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
45 		if (ix < 0x39800000) {	/* |x| < 2**-12 */
46 			if ((int)x == 0) {
47 				*sn = x;	/* x with inexact if x != 0 */
48 				*cs = 1;
49 				return;
50 			}
51 		}
52 		__kernel_sincosdf(x, sn, cs);
53 		return;
54 	}
55 
56 	if (ix <= 0x407b53d1) {		/* |x| ~<= 5*pi/4 */
57 		if (ix <= 0x4016cbe3) {	/* |x| ~<= 3pi/4 */
58 			if (hx > 0) {
59 				__kernel_sincosdf(x - p1pio2, cs, sn);
60 				*cs = -*cs;
61 			} else {
62 				__kernel_sincosdf(x + p1pio2, cs, sn);
63 				*sn = -*sn;
64 			}
65 		} else {
66 			if (hx > 0)
67 				__kernel_sincosdf(x - p2pio2, sn, cs);
68 			else
69 				__kernel_sincosdf(x + p2pio2, sn, cs);
70 			*sn = -*sn;
71 			*cs = -*cs;
72 		}
73 		return;
74 	}
75 
76 	if (ix <= 0x40e231d5) {		/* |x| ~<= 9*pi/4 */
77 		if (ix <= 0x40afeddf) {	/* |x| ~<= 7*pi/4 */
78 			if (hx > 0) {
79 				__kernel_sincosdf(x - p3pio2, cs, sn);
80 				*sn = -*sn;
81 			} else {
82 				__kernel_sincosdf(x + p3pio2, cs, sn);
83 				*cs = -*cs;
84 			}
85 		} else {
86 			if (hx > 0)
87 				__kernel_sincosdf(x - p4pio2, sn, cs);
88 			else
89 				__kernel_sincosdf(x + p4pio2, sn, cs);
90 		}
91 		return;
92 	}
93 
94 	/* If x = Inf or NaN, then sin(x) = NaN and cos(x) = NaN. */
95 	if (ix >= 0x7f800000) {
96 		*sn = x - x;
97 		*cs = x - x;
98 		return;
99 	}
100 
101 	/* Argument reduction. */
102 	n = __ieee754_rem_pio2f(x, &y);
103 	__kernel_sincosdf(y, &s, &c);
104 
105 	switch(n & 3) {
106 	case 0:
107 		*sn = s;
108 		*cs = c;
109 		break;
110 	case 1:
111 		*sn = c;
112 		*cs = -s;
113 		break;
114 	case 2:
115 		*sn = -s;
116 		*cs = -c;
117 		break;
118 	default:
119 		*sn = -c;
120 		*cs = s;
121 	}
122 }
123 
124 
125