source: trunk/libs/newlib/src/newlib/libm/math/sf_cos.c @ 471

/* sf_cos.c -- float version of s_cos.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__
static const float one=1.0;
#else
static float one=1.0;
#endif

#ifdef __STDC__
        float cosf(float x)
#else
        float cosf(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 <= 0x3f490fd8) return __kernel_cosf(x,z);

    /* cos(Inf or NaN) is NaN */
        else if (!FLT_UWORD_IS_FINITE(ix)) return x-x;

    /* argument reduction needed */
        else {
            n = __ieee754_rem_pio2f(x,y);
            switch(n&3) {
                case 0: return  __kernel_cosf(y[0],y[1]);
                case 1: return -__kernel_sinf(y[0],y[1],1);
                case 2: return -__kernel_cosf(y[0],y[1]);
                default:
                        return  __kernel_sinf(y[0],y[1],1);
            }
        }
}

#ifdef _DOUBLE_IS_32BITS

#ifdef __STDC__
        double cos(double x)
#else
        double cos(x)
        double x;
#endif
{
        return (double) cosf((float) x);
}

#endif /* defined(_DOUBLE_IS_32BITS) */