/*===--------------------------------------------------------------------------
 *                   ROCm Device Libraries
 *
 * This file is distributed under the University of Illinois Open Source
 * License. See LICENSE.TXT for details.
 *===------------------------------------------------------------------------*/

// Trigonometric reduction for half_cos,sin,tan

struct redret {
    int i;
    float r;
};

struct redret
__half_red(float x)
{
    const float twobypi = 0x1.45f306p-1f;
    const float pb2_a = 0x1.92p+0f;
    const float pb2_b = 0x1.fap-12f;
    const float pb2_c = 0x1.54p-20f;
    const float pb2_d = 0x1.10p-30f;
    const float pb2_e = 0x1.68p-39f;
    const float pb2_f = 0x1.846988p-48f;

    float fn = rint(x * twobypi);

    struct redret ret;
    ret.i = (int)fn & 0x3;
    ret.r = mad(fn, -pb2_f,
	       mad(fn, -pb2_e,
		   mad(fn, -pb2_d,
		       mad(fn, -pb2_c,
			   mad(fn, -pb2_b,
			       mad(fn, -pb2_a, x))))));

    return ret;
}