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1/*2 * Copyright (c) 2011 Broadcom Corporation3 *4 * Permission to use, copy, modify, and/or distribute this software for any5 * purpose with or without fee is hereby granted, provided that the above6 * copyright notice and this permission notice appear in all copies.7 *8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY11 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION13 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN14 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.15 */16#include <linux/module.h>17#include <linux/cordic.h>18 19static const s32 arctan_table[] = {20 2949120,21 1740967,22 919879,23 466945,24 234379,25 117304,26 58666,27 29335,28 14668,29 7334,30 3667,31 1833,32 917,33 458,34 229,35 115,36 57,37 2938};39 40/*41 * cordic_calc_iq() - calculates the i/q coordinate for given angle42 *43 * theta: angle in degrees for which i/q coordinate is to be calculated44 * coord: function output parameter holding the i/q coordinate45 */46struct cordic_iq cordic_calc_iq(s32 theta)47{48 struct cordic_iq coord;49 s32 angle, valtmp;50 unsigned iter;51 int signx = 1;52 int signtheta;53 54 coord.i = CORDIC_ANGLE_GEN;55 coord.q = 0;56 angle = 0;57 58 theta = CORDIC_FIXED(theta);59 signtheta = (theta < 0) ? -1 : 1;60 theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) -61 CORDIC_FIXED(180) * signtheta;62 63 if (CORDIC_FLOAT(theta) > 90) {64 theta -= CORDIC_FIXED(180);65 signx = -1;66 } else if (CORDIC_FLOAT(theta) < -90) {67 theta += CORDIC_FIXED(180);68 signx = -1;69 }70 71 for (iter = 0; iter < CORDIC_NUM_ITER; iter++) {72 if (theta > angle) {73 valtmp = coord.i - (coord.q >> iter);74 coord.q += (coord.i >> iter);75 angle += arctan_table[iter];76 } else {77 valtmp = coord.i + (coord.q >> iter);78 coord.q -= (coord.i >> iter);79 angle -= arctan_table[iter];80 }81 coord.i = valtmp;82 }83 84 coord.i *= signx;85 coord.q *= signx;86 return coord;87}88EXPORT_SYMBOL(cordic_calc_iq);89 90MODULE_DESCRIPTION("CORDIC algorithm");91MODULE_AUTHOR("Broadcom Corporation");92MODULE_LICENSE("Dual BSD/GPL");93