Author: adrian Date: Sat May 14 23:33:13 2016 New Revision: 299785 URL: https://svnweb.freebsd.org/changeset/base/299785
Log: [bwn] add an implementation of "cordic" and imaginary math. This is used by the PHY-N code. Obtained from: http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic Added: head/sys/dev/bwn/if_bwn_cordic.h (contents, props changed) Added: head/sys/dev/bwn/if_bwn_cordic.h ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/sys/dev/bwn/if_bwn_cordic.h Sat May 14 23:33:13 2016 (r299785) @@ -0,0 +1,96 @@ +/*- + * Copyright (c) 2016 Adrian Chadd <[email protected]> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer, + * without modification. + * 2. Redistributions in binary form must reproduce at minimum a disclaimer + * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any + * redistribution must be conditioned upon including a substantially + * similar Disclaimer requirement for further binary redistribution. + * + * NO WARRANTY + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY + * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL + * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, + * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER + * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF + * THE POSSIBILITY OF SUCH DAMAGES. + * + * $FreeBSD$ + */ +#ifndef __IF_BWN_CORDIC_H__ +#define __IF_BWN_CORDIC_H__ + +/* + * These functions are used by the PHY code. + */ + +/* Complex number using 2 32-bit signed integers */ +struct bwn_c32 { + int32_t i; + int32_t q; +}; + +#define CORDIC_CONVERT(value) (((value) >= 0) ? \ + ((((value) >> 15) + 1) >> 1) : \ + -((((-(value)) >> 15) + 1) >> 1)) + +static const uint32_t bwn_arctg[] = { + 2949120, 1740967, 919879, 466945, 234379, 117304, 58666, 29335, 14668, + 7334, 3667, 1833, 917, 458, 229, 115, 57, 29, +}; + +/* http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic */ +static inline struct bwn_c32 +bwn_cordic(int theta) +{ + uint8_t i; + int32_t tmp; + int8_t signx = 1; + uint32_t angle = 0; + struct bwn_c32 ret = { .i = 39797, .q = 0, }; + + while (theta > (180 << 16)) + theta -= (360 << 16); + while (theta < -(180 << 16)) + theta += (360 << 16); + + if (theta > (90 << 16)) { + theta -= (180 << 16); + signx = -1; + } else if (theta < -(90 << 16)) { + theta += (180 << 16); + signx = -1; + } + + for (i = 0; i <= 17; i++) { + if (theta > angle) { + tmp = ret.i - (ret.q >> i); + ret.q += ret.i >> i; + ret.i = tmp; + angle += bwn_arctg[i]; + } else { + tmp = ret.i + (ret.q >> i); + ret.q -= ret.i >> i; + ret.i = tmp; + angle -= bwn_arctg[i]; + } + } + + ret.i *= signx; + ret.q *= signx; + + return ret; +} + +#endif /* __IF_BWN_CORDIC_H__ */ _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
