s_tanf.c revision 97409
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 17static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_tanf.c 97409 2002-05-28 17:51:46Z alfred $"; 18#endif 19 20#include "math.h" 21#include "math_private.h" 22 23 float tanf(float x) 24{ 25 float y[2],z=0.0; 26 int32_t n, ix; 27 28 GET_FLOAT_WORD(ix,x); 29 30 /* |x| ~< pi/4 */ 31 ix &= 0x7fffffff; 32 if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1); 33 34 /* tan(Inf or NaN) is NaN */ 35 else if (ix>=0x7f800000) return x-x; /* NaN */ 36 37 /* argument reduction needed */ 38 else { 39 n = __ieee754_rem_pio2f(x,y); 40 return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even 41 -1 -- n odd */ 42 } 43} 44