1 /* s_tanf.c -- float version of s_tan.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 * Optimized by Bruce D. Evans.
4 */
5
6 /*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
15 */
16
17 #include <sys/cdefs.h>
18 __FBSDID("$FreeBSD$");
19
20 #include <float.h>
21
22 #include "math.h"
23 #define INLINE_KERNEL_TANDF
24 #define INLINE_REM_PIO2F
25 #include "math_private.h"
26 #include "e_rem_pio2f.c"
27 #include "k_tanf.c"
28
29 /* Small multiples of pi/2 rounded to double precision. */
30 static const double
31 t1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
32 t2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
33 t3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
34 t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
35
36 float
tanf(float x)37 tanf(float x)
38 {
39 double y;
40 int32_t n, hx, ix;
41
42 GET_FLOAT_WORD(hx,x);
43 ix = hx & 0x7fffffff;
44
45 if (ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
46 if (ix<0x39800000) /* |x| < 2**-12 */
47 if (((int)x)==0) return x; /* x with inexact if x != 0 */
48 return __kernel_tandf(x,1);
49 }
50 if (ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */
51 if (ix<=0x4016cbe3) /* |x| ~<= 3pi/4 */
52 return __kernel_tandf(x + (hx>0 ? -t1pio2 : t1pio2), -1);
53 else
54 return __kernel_tandf(x + (hx>0 ? -t2pio2 : t2pio2), 1);
55 }
56 if (ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */
57 if (ix<=0x40afeddf) /* |x| ~<= 7*pi/4 */
58 return __kernel_tandf(x + (hx>0 ? -t3pio2 : t3pio2), -1);
59 else
60 return __kernel_tandf(x + (hx>0 ? -t4pio2 : t4pio2), 1);
61 }
62
63 /* tan(Inf or NaN) is NaN */
64 else if (ix>=0x7f800000) return x-x;
65
66 /* general argument reduction needed */
67 else {
68 n = __ieee754_rem_pio2f(x,&y);
69 /* integer parameter: 1 -- n even; -1 -- n odd */
70 return __kernel_tandf(y,1-((n&1)<<1));
71 }
72 }
73