/*
 * Copyright (c) 2011 Broadcom Corporation
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <linux/module.h>
#include <linux/cordic.h>

static const s32 arctan_table[] = {
        2949120,
        1740967,
        919879,
        466945,
        234379,
        117304,
        58666,
        29335,
        14668,
        7334,
        3667,
        1833,
        917,
        458,
        229,
        115,
        57,
        29
};

/*
 * cordic_calc_iq() - calculates the i/q coordinate for given angle
 *
 * theta: angle in degrees for which i/q coordinate is to be calculated
 * coord: function output parameter holding the i/q coordinate
 */
struct cordic_iq cordic_calc_iq(s32 theta)
{
        struct cordic_iq coord;
        s32 angle, valtmp;
        unsigned iter;
        int signx = 1;
        int signtheta;

        coord.i = CORDIC_ANGLE_GEN;
        coord.q = 0;
        angle = 0;

        theta = CORDIC_FIXED(theta);
        signtheta = (theta < 0) ? -1 : 1;
        theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) -
                CORDIC_FIXED(180) * signtheta;

        if (CORDIC_FLOAT(theta) > 90) {
                theta -= CORDIC_FIXED(180);
                signx = -1;
        } else if (CORDIC_FLOAT(theta) < -90) {
                theta += CORDIC_FIXED(180);
                signx = -1;
        }

        for (iter = 0; iter < CORDIC_NUM_ITER; iter++) {
                if (theta > angle) {
                        valtmp = coord.i - (coord.q >> iter);
                        coord.q += (coord.i >> iter);
                        angle += arctan_table[iter];
                } else {
                        valtmp = coord.i + (coord.q >> iter);
                        coord.q -= (coord.i >> iter);
                        angle -= arctan_table[iter];
                }
                coord.i = valtmp;
        }

        coord.i *= signx;
        coord.q *= signx;
        return coord;
}
EXPORT_SYMBOL(cordic_calc_iq);

MODULE_DESCRIPTION("CORDIC algorithm");
MODULE_AUTHOR("Broadcom Corporation");
MODULE_LICENSE("Dual BSD/GPL");