source: trunk/libs/newlib/src/newlib/libm/math/sf_tan.c @ 567

/* sf_tan.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.
 * ====================================================
 */

#include "fdlibm.h"

#ifdef __STDC__
        float tanf(float x)
#else
        float tanf(x)
        float x;
#endif
{
        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 (!FLT_UWORD_IS_FINITE(ix)) 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 */
        }
}

#ifdef _DOUBLE_IS_32BITS

#ifdef __STDC__
        double tan(double x)
#else
        double tan(x)
        double x;
#endif
{
        return (double) tanf((float) x);
}

#endif /* defined(_DOUBLE_IS_32BITS) */