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---
s_tanf.c (1107B)
---
1 /* s_tanf.c -- float version of s_tan.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
16 #ifndef lint
17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_tanf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $";
18 #endif
19
20 #include "math.h"
21 #include "math_private.h"
22
23 float
24 tanf(float x)
25 {
26 float y[2],z=0.0;
27 int32_t n, ix;
28
29 GET_FLOAT_WORD(ix,x);
30
31 /* |x| ~< pi/4 */
32 ix &= 0x7fffffff;
33 if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
34
35 /* tan(Inf or NaN) is NaN */
36 else if (ix>=0x7f800000) return x-x; /* NaN */
37
38 /* argument reduction needed */
39 else {
40 n = __ieee754_rem_pio2f(x,y);
41 return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
42 -1 -- n odd */
43 }
44 }