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      1 /* s_tanf.c -- float version of s_tan.c.
      2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) 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 1.8 2024/05/08 01:40:27 riastradh Exp $");
     19 #endif
     20 
     21 #include "namespace.h"
     22 #include "math.h"
     23 #include "math_private.h"
     24 
     25 __weak_alias(tanf, _tanf)
     26 
     27 float
     28 tanf(float x)
     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