/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
/*
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 * Optimized by Bruce D. Evans.
 */
/*
 * ====================================================
 * 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 "libm.h"

/* Small multiples of pi/2 rounded to double precision. */
static const double
    s1pio2 = 1 * M_PI_2, /* 0x3FF921FB, 0x54442D18 */
    s2pio2 = 2 * M_PI_2, /* 0x400921FB, 0x54442D18 */
    s3pio2 = 3 * M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
    s4pio2 = 4 * M_PI_2; /* 0x401921FB, 0x54442D18 */

float sinf(float x)
{
    double y;
    uint32_t ix;
    int n, sign;

    GET_FLOAT_WORD(ix, x);
    sign = ix >> 31;
    ix &= 0x7fffffff;

    if (ix <= 0x3f490fda)
    { /* |x| ~<= pi/4 */
        if (ix < 0x39800000)
        { /* |x| < 2**-12 */
            /* raise inexact if x!=0 and underflow if subnormal */
            FORCE_EVAL(ix < 0x00800000 ? x / 0x1p120f : x + 0x1p120f);
            return x;
        }
        return __sindf(x);
    }
    if (ix <= 0x407b53d1)
    { /* |x| ~<= 5*pi/4 */
        if (ix <= 0x4016cbe3)
        { /* |x| ~<= 3pi/4 */
            if (sign)
                return -__cosdf(x + s1pio2);
            else
                return __cosdf(x - s1pio2);
        }
        return __sindf(sign ? -(x + s2pio2) : -(x - s2pio2));
    }
    if (ix <= 0x40e231d5)
    { /* |x| ~<= 9*pi/4 */
        if (ix <= 0x40afeddf)
        { /* |x| ~<= 7*pi/4 */
            if (sign)
                return __cosdf(x + s3pio2);
            else
                return -__cosdf(x - s3pio2);
        }
        return __sindf(sign ? x + s4pio2 : x - s4pio2);
    }

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

    /* general argument reduction needed */
    n = __rem_pio2f(x, &y);
    switch (n & 3)
    {
    case 0:
        return __sindf(y);
    case 1:
        return __cosdf(y);
    case 2:
        return __sindf(-y);
    default:
        return -__cosdf(y);
    }
}
