1 /* 2 * Copyright (c) 2011 Broadcom Corporation 3 * 4 * Permission to use, copy, modify, and/or distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 11 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 13 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 14 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 #ifndef __CORDIC_H_ 17 #define __CORDIC_H_ 18 19 #include <linux/types.h> 20 21 #define CORDIC_ANGLE_GEN 39797 22 #define CORDIC_PRECISION_SHIFT 16 23 #define CORDIC_NUM_ITER (CORDIC_PRECISION_SHIFT + 2) 24 25 #define CORDIC_FIXED(X) ((s32)((X) << CORDIC_PRECISION_SHIFT)) 26 #define CORDIC_FLOAT(X) (((X) >= 0) \ 27 ? ((((X) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1) \ 28 : -((((-(X)) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1)) 29 30 /** 31 * struct cordic_iq - i/q coordinate. 32 * 33 * @i: real part of coordinate (in phase). 34 * @q: imaginary part of coordinate (quadrature). 35 */ 36 struct cordic_iq { 37 s32 i; 38 s32 q; 39 }; 40 41 /** 42 * cordic_calc_iq() - calculates the i/q coordinate for given angle. 43 * 44 * @theta: angle in degrees for which i/q coordinate is to be calculated. 45 * @coord: function output parameter holding the i/q coordinate. 46 * 47 * The function calculates the i/q coordinate for a given angle using the 48 * CORDIC algorithm. The coordinate consists of a real (i) and an 49 * imaginary (q) part. The real part is essentially the cosine of the 50 * angle and the imaginary part is the sine of the angle. The returned 51 * values are scaled by 2^16 for precision. The range for theta is 52 * for -180 degrees to +180 degrees. Passed values outside this range are 53 * converted before doing the actual calculation. 54 */ 55 struct cordic_iq cordic_calc_iq(s32 theta); 56 57 #endif /* __CORDIC_H_ */ 58