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 #include <sys/cdefs.h> 17 #if defined(LIBM_SCCS) && !defined(lint) 18 __RCSID("$NetBSD: s_tanf.c,v 1.5 1997/10/09 11:33:38 lukem Exp $"); 19 #endif 20 21 #include "math.h" 22 #include "math_private.h" 23 24 #ifdef __STDC__ 25 float tanf(float x) 26 #else 27 float tanf(x) 28 float x; 29 #endif 30 { 31 float y[2],z=0.0; 32 int32_t n, ix; 33 34 GET_FLOAT_WORD(ix,x); 35 36 /* |x| ~< pi/4 */ 37 ix &= 0x7fffffff; 38 if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1); 39 40 /* tan(Inf or NaN) is NaN */ 41 else if (ix>=0x7f800000) return x-x; /* NaN */ 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