projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 10f8113e AS |
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 | #include <linux/module.h> | |
| 17 | #include <linux/cordic.h> | |
| 18 | ||
| 10f8113e AS |
19 | static 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 | 29 | |
| 38 | }; | |
| 39 | ||
| 40 | /* | |
| 41 | * cordic_calc_iq() - calculates the i/q coordinate for given angle | |
| 42 | * | |
| 43 | * theta: angle in degrees for which i/q coordinate is to be calculated | |
| 44 | * coord: function output parameter holding the i/q coordinate | |
| 45 | */ | |
| 46 | struct 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 | ||
| 58d81d64 | 58 | theta = CORDIC_FIXED(theta); |
| 10f8113e | 59 | signtheta = (theta < 0) ? -1 : 1; |
| 58d81d64 PL |
60 | theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) - |
| 61 | CORDIC_FIXED(180) * signtheta; | |
| 10f8113e | 62 | |
| 58d81d64 PL |
63 | if (CORDIC_FLOAT(theta) > 90) { |
| 64 | theta -= CORDIC_FIXED(180); | |
| 10f8113e | 65 | signx = -1; |
| 58d81d64 PL |
66 | } else if (CORDIC_FLOAT(theta) < -90) { |
| 67 | theta += CORDIC_FIXED(180); | |
| 10f8113e AS |
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 | } | |
| 88 | EXPORT_SYMBOL(cordic_calc_iq); | |
| 89 | ||
| d89ce936 | 90 | MODULE_DESCRIPTION("CORDIC algorithm"); |
| 10f8113e AS |
91 | MODULE_AUTHOR("Broadcom Corporation"); |
| 92 | MODULE_LICENSE("Dual BSD/GPL"); |