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 | #if defined(LIBM_SCCS) && !defined(lint) |
17 | static char rcsid[] = "$NetBSD: s_tanf.c,v 1.4 1995/05/10 20:48:20 jtc Exp $" ; |
18 | #endif |
19 | |
20 | #include <errno.h> |
21 | #include <math.h> |
22 | #include <math_private.h> |
23 | #include <libm-alias-float.h> |
24 | |
25 | float __tanf(float x) |
26 | { |
27 | float y[2],z=0.0; |
28 | int32_t n, ix; |
29 | |
30 | GET_FLOAT_WORD(ix,x); |
31 | |
32 | /* |x| ~< pi/4 */ |
33 | ix &= 0x7fffffff; |
34 | if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1); |
35 | |
36 | /* tan(Inf or NaN) is NaN */ |
37 | else if (ix>=0x7f800000) { |
38 | if (ix==0x7f800000) |
39 | __set_errno (EDOM); |
40 | return x-x; /* NaN */ |
41 | } |
42 | |
43 | /* argument reduction needed */ |
44 | else { |
45 | n = __ieee754_rem_pio2f(x,y); |
46 | return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even |
47 | -1 -- n odd */ |
48 | } |
49 | } |
50 | libm_alias_float (__tan, tan) |
51 | |