1*36fcc18dSAdrian Chadd /*-
2*36fcc18dSAdrian Chadd * Copyright (c) 2016 Adrian Chadd <adrian@FreeBSD.org>
3*36fcc18dSAdrian Chadd * All rights reserved.
4*36fcc18dSAdrian Chadd *
5*36fcc18dSAdrian Chadd * Redistribution and use in source and binary forms, with or without
6*36fcc18dSAdrian Chadd * modification, are permitted provided that the following conditions
7*36fcc18dSAdrian Chadd * are met:
8*36fcc18dSAdrian Chadd * 1. Redistributions of source code must retain the above copyright
9*36fcc18dSAdrian Chadd * notice, this list of conditions and the following disclaimer,
10*36fcc18dSAdrian Chadd * without modification.
11*36fcc18dSAdrian Chadd * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12*36fcc18dSAdrian Chadd * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13*36fcc18dSAdrian Chadd * redistribution must be conditioned upon including a substantially
14*36fcc18dSAdrian Chadd * similar Disclaimer requirement for further binary redistribution.
15*36fcc18dSAdrian Chadd *
16*36fcc18dSAdrian Chadd * NO WARRANTY
17*36fcc18dSAdrian Chadd * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18*36fcc18dSAdrian Chadd * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19*36fcc18dSAdrian Chadd * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
20*36fcc18dSAdrian Chadd * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21*36fcc18dSAdrian Chadd * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
22*36fcc18dSAdrian Chadd * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23*36fcc18dSAdrian Chadd * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24*36fcc18dSAdrian Chadd * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25*36fcc18dSAdrian Chadd * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26*36fcc18dSAdrian Chadd * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27*36fcc18dSAdrian Chadd * THE POSSIBILITY OF SUCH DAMAGES.
28*36fcc18dSAdrian Chadd */
29*36fcc18dSAdrian Chadd #ifndef __IF_BWN_CORDIC_H__
30*36fcc18dSAdrian Chadd #define __IF_BWN_CORDIC_H__
31*36fcc18dSAdrian Chadd
32*36fcc18dSAdrian Chadd /*
33*36fcc18dSAdrian Chadd * These functions are used by the PHY code.
34*36fcc18dSAdrian Chadd */
35*36fcc18dSAdrian Chadd
36*36fcc18dSAdrian Chadd /* Complex number using 2 32-bit signed integers */
37*36fcc18dSAdrian Chadd struct bwn_c32 {
38*36fcc18dSAdrian Chadd int32_t i;
39*36fcc18dSAdrian Chadd int32_t q;
40*36fcc18dSAdrian Chadd };
41*36fcc18dSAdrian Chadd
42*36fcc18dSAdrian Chadd #define CORDIC_CONVERT(value) (((value) >= 0) ? \
43*36fcc18dSAdrian Chadd ((((value) >> 15) + 1) >> 1) : \
44*36fcc18dSAdrian Chadd -((((-(value)) >> 15) + 1) >> 1))
45*36fcc18dSAdrian Chadd
46*36fcc18dSAdrian Chadd static const uint32_t bwn_arctg[] = {
47*36fcc18dSAdrian Chadd 2949120, 1740967, 919879, 466945, 234379, 117304, 58666, 29335, 14668,
48*36fcc18dSAdrian Chadd 7334, 3667, 1833, 917, 458, 229, 115, 57, 29,
49*36fcc18dSAdrian Chadd };
50*36fcc18dSAdrian Chadd
51*36fcc18dSAdrian Chadd /* http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic */
52*36fcc18dSAdrian Chadd static inline struct bwn_c32
bwn_cordic(int theta)53*36fcc18dSAdrian Chadd bwn_cordic(int theta)
54*36fcc18dSAdrian Chadd {
55*36fcc18dSAdrian Chadd uint8_t i;
56*36fcc18dSAdrian Chadd int32_t tmp;
57*36fcc18dSAdrian Chadd int8_t signx = 1;
58*36fcc18dSAdrian Chadd uint32_t angle = 0;
59*36fcc18dSAdrian Chadd struct bwn_c32 ret = { .i = 39797, .q = 0, };
60*36fcc18dSAdrian Chadd
61*36fcc18dSAdrian Chadd while (theta > (180 << 16))
62*36fcc18dSAdrian Chadd theta -= (360 << 16);
63*36fcc18dSAdrian Chadd while (theta < -(180 << 16))
64*36fcc18dSAdrian Chadd theta += (360 << 16);
65*36fcc18dSAdrian Chadd
66*36fcc18dSAdrian Chadd if (theta > (90 << 16)) {
67*36fcc18dSAdrian Chadd theta -= (180 << 16);
68*36fcc18dSAdrian Chadd signx = -1;
69*36fcc18dSAdrian Chadd } else if (theta < -(90 << 16)) {
70*36fcc18dSAdrian Chadd theta += (180 << 16);
71*36fcc18dSAdrian Chadd signx = -1;
72*36fcc18dSAdrian Chadd }
73*36fcc18dSAdrian Chadd
74*36fcc18dSAdrian Chadd for (i = 0; i <= 17; i++) {
75*36fcc18dSAdrian Chadd if (theta > angle) {
76*36fcc18dSAdrian Chadd tmp = ret.i - (ret.q >> i);
77*36fcc18dSAdrian Chadd ret.q += ret.i >> i;
78*36fcc18dSAdrian Chadd ret.i = tmp;
79*36fcc18dSAdrian Chadd angle += bwn_arctg[i];
80*36fcc18dSAdrian Chadd } else {
81*36fcc18dSAdrian Chadd tmp = ret.i + (ret.q >> i);
82*36fcc18dSAdrian Chadd ret.q -= ret.i >> i;
83*36fcc18dSAdrian Chadd ret.i = tmp;
84*36fcc18dSAdrian Chadd angle -= bwn_arctg[i];
85*36fcc18dSAdrian Chadd }
86*36fcc18dSAdrian Chadd }
87*36fcc18dSAdrian Chadd
88*36fcc18dSAdrian Chadd ret.i *= signx;
89*36fcc18dSAdrian Chadd ret.q *= signx;
90*36fcc18dSAdrian Chadd
91*36fcc18dSAdrian Chadd return ret;
92*36fcc18dSAdrian Chadd }
93*36fcc18dSAdrian Chadd
94*36fcc18dSAdrian Chadd #endif /* __IF_BWN_CORDIC_H__ */
95