/*
   * 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>
  
  #define CORDIC_ANGLE_GEN	39797
  #define CORDIC_PRECISION_SHIFT	16
  #define	CORDIC_NUM_ITER		(CORDIC_PRECISION_SHIFT + 2)
  
  #define	FIXED(X)	((s32)((X) << CORDIC_PRECISION_SHIFT))
  #define	FLOAT(X)	(((X) >= 0) \
  		? ((((X) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1) \
  		: -((((-(X)) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1))
  
  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 = FIXED(theta);
  	signtheta = (theta < 0) ? -1 : 1;
  	theta = ((theta + FIXED(180) * signtheta) % FIXED(360)) -
  		FIXED(180) * signtheta;
  
  	if (FLOAT(theta) > 90) {
  		theta -= FIXED(180);
  		signx = -1;
  	} else if (FLOAT(theta) < -90) {
  		theta += 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");