/home/jaouen/pok_official/pok/trunk/libpok/libm/tanf.c

/*
 *                               POK header
 * 
 * The following file is a part of the POK project. Any modification should
 * made according to the POK licence. You CANNOT use this file or a part of
 * this file is this part of a file for your own project
 *
 * For more information on the POK licence, please see our LICENCE FILE
 *
 * Please follow the coding guidelines described in doc/CODING_GUIDELINES
 *
 *                                      Copyright (c) 2007-2009 POK team 
 *
 * Created by julien on Fri Jan 30 14:41:34 2009 
 */

/* s_tanf.c -- float version of s_tan.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#ifdef POK_NEEDS_LIBMATH

#include <libm.h>
#include "math_private.h"

float
tanf(float x)
{
        float y[2],z=0.0;
        int32_t n, ix;

        GET_FLOAT_WORD(ix,x);

    /* |x| ~< pi/4 */
        ix &= 0x7fffffff;
        if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);

    /* tan(Inf or NaN) is NaN */
        else if (ix>=0x7f800000) return x-x;            /* NaN */

    /* argument reduction needed */
        else {
            n = __ieee754_rem_pio2f(x,y);
            return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /*   1 -- n even
                                                              -1 -- n odd */
        }
}

#endif