18c2ecf20Sopenharmony_ci/* 28c2ecf20Sopenharmony_ci * Copyright (c) 2011 Broadcom Corporation 38c2ecf20Sopenharmony_ci * 48c2ecf20Sopenharmony_ci * Permission to use, copy, modify, and/or distribute this software for any 58c2ecf20Sopenharmony_ci * purpose with or without fee is hereby granted, provided that the above 68c2ecf20Sopenharmony_ci * copyright notice and this permission notice appear in all copies. 78c2ecf20Sopenharmony_ci * 88c2ecf20Sopenharmony_ci * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 98c2ecf20Sopenharmony_ci * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 108c2ecf20Sopenharmony_ci * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 118c2ecf20Sopenharmony_ci * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 128c2ecf20Sopenharmony_ci * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 138c2ecf20Sopenharmony_ci * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 148c2ecf20Sopenharmony_ci * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 158c2ecf20Sopenharmony_ci */ 168c2ecf20Sopenharmony_ci#include <linux/module.h> 178c2ecf20Sopenharmony_ci#include <linux/cordic.h> 188c2ecf20Sopenharmony_ci 198c2ecf20Sopenharmony_cistatic const s32 arctan_table[] = { 208c2ecf20Sopenharmony_ci 2949120, 218c2ecf20Sopenharmony_ci 1740967, 228c2ecf20Sopenharmony_ci 919879, 238c2ecf20Sopenharmony_ci 466945, 248c2ecf20Sopenharmony_ci 234379, 258c2ecf20Sopenharmony_ci 117304, 268c2ecf20Sopenharmony_ci 58666, 278c2ecf20Sopenharmony_ci 29335, 288c2ecf20Sopenharmony_ci 14668, 298c2ecf20Sopenharmony_ci 7334, 308c2ecf20Sopenharmony_ci 3667, 318c2ecf20Sopenharmony_ci 1833, 328c2ecf20Sopenharmony_ci 917, 338c2ecf20Sopenharmony_ci 458, 348c2ecf20Sopenharmony_ci 229, 358c2ecf20Sopenharmony_ci 115, 368c2ecf20Sopenharmony_ci 57, 378c2ecf20Sopenharmony_ci 29 388c2ecf20Sopenharmony_ci}; 398c2ecf20Sopenharmony_ci 408c2ecf20Sopenharmony_ci/* 418c2ecf20Sopenharmony_ci * cordic_calc_iq() - calculates the i/q coordinate for given angle 428c2ecf20Sopenharmony_ci * 438c2ecf20Sopenharmony_ci * theta: angle in degrees for which i/q coordinate is to be calculated 448c2ecf20Sopenharmony_ci * coord: function output parameter holding the i/q coordinate 458c2ecf20Sopenharmony_ci */ 468c2ecf20Sopenharmony_cistruct cordic_iq cordic_calc_iq(s32 theta) 478c2ecf20Sopenharmony_ci{ 488c2ecf20Sopenharmony_ci struct cordic_iq coord; 498c2ecf20Sopenharmony_ci s32 angle, valtmp; 508c2ecf20Sopenharmony_ci unsigned iter; 518c2ecf20Sopenharmony_ci int signx = 1; 528c2ecf20Sopenharmony_ci int signtheta; 538c2ecf20Sopenharmony_ci 548c2ecf20Sopenharmony_ci coord.i = CORDIC_ANGLE_GEN; 558c2ecf20Sopenharmony_ci coord.q = 0; 568c2ecf20Sopenharmony_ci angle = 0; 578c2ecf20Sopenharmony_ci 588c2ecf20Sopenharmony_ci theta = CORDIC_FIXED(theta); 598c2ecf20Sopenharmony_ci signtheta = (theta < 0) ? -1 : 1; 608c2ecf20Sopenharmony_ci theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) - 618c2ecf20Sopenharmony_ci CORDIC_FIXED(180) * signtheta; 628c2ecf20Sopenharmony_ci 638c2ecf20Sopenharmony_ci if (CORDIC_FLOAT(theta) > 90) { 648c2ecf20Sopenharmony_ci theta -= CORDIC_FIXED(180); 658c2ecf20Sopenharmony_ci signx = -1; 668c2ecf20Sopenharmony_ci } else if (CORDIC_FLOAT(theta) < -90) { 678c2ecf20Sopenharmony_ci theta += CORDIC_FIXED(180); 688c2ecf20Sopenharmony_ci signx = -1; 698c2ecf20Sopenharmony_ci } 708c2ecf20Sopenharmony_ci 718c2ecf20Sopenharmony_ci for (iter = 0; iter < CORDIC_NUM_ITER; iter++) { 728c2ecf20Sopenharmony_ci if (theta > angle) { 738c2ecf20Sopenharmony_ci valtmp = coord.i - (coord.q >> iter); 748c2ecf20Sopenharmony_ci coord.q += (coord.i >> iter); 758c2ecf20Sopenharmony_ci angle += arctan_table[iter]; 768c2ecf20Sopenharmony_ci } else { 778c2ecf20Sopenharmony_ci valtmp = coord.i + (coord.q >> iter); 788c2ecf20Sopenharmony_ci coord.q -= (coord.i >> iter); 798c2ecf20Sopenharmony_ci angle -= arctan_table[iter]; 808c2ecf20Sopenharmony_ci } 818c2ecf20Sopenharmony_ci coord.i = valtmp; 828c2ecf20Sopenharmony_ci } 838c2ecf20Sopenharmony_ci 848c2ecf20Sopenharmony_ci coord.i *= signx; 858c2ecf20Sopenharmony_ci coord.q *= signx; 868c2ecf20Sopenharmony_ci return coord; 878c2ecf20Sopenharmony_ci} 888c2ecf20Sopenharmony_ciEXPORT_SYMBOL(cordic_calc_iq); 898c2ecf20Sopenharmony_ci 908c2ecf20Sopenharmony_ciMODULE_DESCRIPTION("CORDIC algorithm"); 918c2ecf20Sopenharmony_ciMODULE_AUTHOR("Broadcom Corporation"); 928c2ecf20Sopenharmony_ciMODULE_LICENSE("Dual BSD/GPL"); 93