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 }