s_tanf.c revision 2116 
12116Sjkh/* s_tanf.c -- float version of s_tan.c.
22116Sjkh * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
32116Sjkh */
42116Sjkh
52116Sjkh/*
62116Sjkh * ====================================================
72116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
82116Sjkh *
92116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business.
102116Sjkh * Permission to use, copy, modify, and distribute this
112116Sjkh * software is freely granted, provided that this notice
122116Sjkh * is preserved.
132116Sjkh * ====================================================
142116Sjkh */
152116Sjkh
162116Sjkh#ifndef lint
172116Sjkhstatic char rcsid[] = "$Id: s_tanf.c,v 1.2 1994/08/18 23:10:20 jtc Exp $";
182116Sjkh#endif
192116Sjkh
202116Sjkh#include "math.h"
212116Sjkh#include "math_private.h"
222116Sjkh
232116Sjkh#ifdef __STDC__
242116Sjkh	float tanf(float x)
252116Sjkh#else
262116Sjkh	float tanf(x)
272116Sjkh	float x;
282116Sjkh#endif
292116Sjkh{
302116Sjkh	float y[2],z=0.0;
312116Sjkh	int32_t n, ix;
322116Sjkh
332116Sjkh	GET_FLOAT_WORD(ix,x);
342116Sjkh
352116Sjkh    /* |x| ~< pi/4 */
362116Sjkh	ix &= 0x7fffffff;
372116Sjkh	if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
382116Sjkh
392116Sjkh    /* tan(Inf or NaN) is NaN */
402116Sjkh	else if (ix>=0x7f800000) return x-x;		/* NaN */
412116Sjkh
422116Sjkh    /* argument reduction needed */
432116Sjkh	else {
442116Sjkh	    n = __ieee754_rem_pio2f(x,y);
452116Sjkh	    return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /*   1 -- n even
462116Sjkh							      -1 -- n odd */
472116Sjkh	}
482116Sjkh}
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