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58d81d64e0
Now that these macros are in header file, we can eventually clean up the duplicate macros present in the drivers that utilize the same cordic algorithm implementation. Also add CORDIC_ prefix to nonprefixed macros. Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com> Signed-off-by: Priit Laes <plaes@plaes.org> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
92 lines
2.2 KiB
C
92 lines
2.2 KiB
C
/*
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* Copyright (c) 2011 Broadcom Corporation
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <linux/module.h>
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#include <linux/cordic.h>
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static const s32 arctan_table[] = {
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2949120,
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1740967,
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919879,
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466945,
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234379,
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117304,
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58666,
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29335,
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14668,
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7334,
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3667,
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1833,
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917,
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458,
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229,
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115,
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57,
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29
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};
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/*
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* cordic_calc_iq() - calculates the i/q coordinate for given angle
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*
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* theta: angle in degrees for which i/q coordinate is to be calculated
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* coord: function output parameter holding the i/q coordinate
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*/
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struct cordic_iq cordic_calc_iq(s32 theta)
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{
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struct cordic_iq coord;
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s32 angle, valtmp;
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unsigned iter;
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int signx = 1;
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int signtheta;
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coord.i = CORDIC_ANGLE_GEN;
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coord.q = 0;
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angle = 0;
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theta = CORDIC_FIXED(theta);
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signtheta = (theta < 0) ? -1 : 1;
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theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) -
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CORDIC_FIXED(180) * signtheta;
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if (CORDIC_FLOAT(theta) > 90) {
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theta -= CORDIC_FIXED(180);
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signx = -1;
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} else if (CORDIC_FLOAT(theta) < -90) {
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theta += CORDIC_FIXED(180);
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signx = -1;
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}
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for (iter = 0; iter < CORDIC_NUM_ITER; iter++) {
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if (theta > angle) {
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valtmp = coord.i - (coord.q >> iter);
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coord.q += (coord.i >> iter);
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angle += arctan_table[iter];
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} else {
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valtmp = coord.i + (coord.q >> iter);
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coord.q -= (coord.i >> iter);
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angle -= arctan_table[iter];
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}
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coord.i = valtmp;
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}
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coord.i *= signx;
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coord.q *= signx;
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return coord;
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}
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EXPORT_SYMBOL(cordic_calc_iq);
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MODULE_DESCRIPTION("CORDIC algorithm");
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MODULE_AUTHOR("Broadcom Corporation");
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MODULE_LICENSE("Dual BSD/GPL");
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