/* * 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");