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.
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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
14 * ====================================================
15 * FreeBSD SVN: 176569 (2008-02-25)
19 #define INLINE_KERNEL_TANDF
20 #define INLINE_REM_PIO2F
21 #include "math_private.h"
22 #include "e_rem_pio2f.c"
25 /* Small multiples of pi/2 rounded to double precision. */
27 t1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
28 t2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
29 t3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
30 t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
41 if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
42 if(ix<0x39800000) /* |x| < 2**-12 */
43 if(((int)x)==0) return x; /* x with inexact if x != 0 */
44 return __kernel_tandf(x,1);
46 if(ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */
47 if(ix<=0x4016cbe3) /* |x| ~<= 3pi/4 */
48 return __kernel_tandf(x + (hx>0 ? -t1pio2 : t1pio2), -1);
50 return __kernel_tandf(x + (hx>0 ? -t2pio2 : t2pio2), 1);
52 if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */
53 if(ix<=0x40afeddf) /* |x| ~<= 7*pi/4 */
54 return __kernel_tandf(x + (hx>0 ? -t3pio2 : t3pio2), -1);
56 return __kernel_tandf(x + (hx>0 ? -t4pio2 : t4pio2), 1);
59 /* tan(Inf or NaN) is NaN */
60 else if (ix>=0x7f800000) return x-x;
62 /* general argument reduction needed */
64 n = __libm_rem_pio2f(x,&y);
65 /* integer parameter: 1 -- n even; -1 -- n odd */
66 return __kernel_tandf(y,1-((n&1)<<1));