1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
/* s_tanf.c -- float version of s_tan.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
* Optimized by Bruce D. Evans.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#ifndef lint
static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_tanf.c,v 1.14 2005/11/28 05:35:32 bde Exp $";
#endif
#include "math.h"
#define INLINE_KERNEL_TANDF
#include "math_private.h"
#include "k_tanf.c"
/* Small multiples of pi/2 rounded to double precision. */
static const double
t1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
t2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
t3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
float
tanf(float x)
{
float y[2];
int32_t n, hx, ix;
GET_FLOAT_WORD(hx,x);
ix = hx & 0x7fffffff;
if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
if(ix<0x39800000) /* |x| < 2**-12 */
if(((int)x)==0) return x; /* x with inexact if x != 0 */
return __kernel_tandf(x,1);
}
if(ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */
if(ix<=0x4016cbe3) /* |x| ~<= 3pi/4 */
return __kernel_tandf(x + (hx>0 ? -t1pio2 : t1pio2), -1);
else
return __kernel_tandf(x + (hx>0 ? -t2pio2 : t2pio2), 1);
}
if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */
if(ix<=0x40afeddf) /* |x| ~<= 7*pi/4 */
return __kernel_tandf(x + (hx>0 ? -t3pio2 : t3pio2), -1);
else
return __kernel_tandf(x + (hx>0 ? -t4pio2 : t4pio2), 1);
}
/* tan(Inf or NaN) is NaN */
else if (ix>=0x7f800000) return x-x;
/* general argument reduction needed */
else {
n = __ieee754_rem_pio2f(x,y);
/* integer parameter: 1 -- n even; -1 -- n odd */
return __kernel_tandf((double)y[0]+y[1],1-((n&1)<<1));
}
}
|
