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 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 ``` ``````/* * 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 #include 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 = CORDIC_FIXED(theta); signtheta = (theta < 0) ? -1 : 1; theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) - CORDIC_FIXED(180) * signtheta; if (CORDIC_FLOAT(theta) > 90) { theta -= CORDIC_FIXED(180); signx = -1; } else if (CORDIC_FLOAT(theta) < -90) { theta += CORDIC_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"); ``````