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[] = "$Id$"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 #ifdef __STDC__ 24 float tanf(float x) 25 #else 26 float tanf(x) 27 float x; 28 #endif 29 { 30 float y[2],z=0.0; 31 int32_t n, ix; 32 33 GET_FLOAT_WORD(ix,x); 34 35 /* |x| ~< pi/4 */ 36 ix &= 0x7fffffff; 37 if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1); 38 39 /* tan(Inf or NaN) is NaN */ 40 else if (ix>=0x7f800000) return x-x; /* NaN */ 41 42 /* argument reduction needed */ 43 else { 44 n = __ieee754_rem_pio2f(x,y); 45 return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even 46 -1 -- n odd */ 47 } 48 } 49