58 строки
2.1 KiB
C
58 строки
2.1 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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#ifndef __CORDIC_H_
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#define __CORDIC_H_
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#include <linux/types.h>
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#define CORDIC_ANGLE_GEN 39797
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#define CORDIC_PRECISION_SHIFT 16
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#define CORDIC_NUM_ITER (CORDIC_PRECISION_SHIFT + 2)
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#define CORDIC_FIXED(X) ((s32)((X) << CORDIC_PRECISION_SHIFT))
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#define CORDIC_FLOAT(X) (((X) >= 0) \
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? ((((X) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1) \
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: -((((-(X)) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1))
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/**
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* struct cordic_iq - i/q coordinate.
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*
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* @i: real part of coordinate (in phase).
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* @q: imaginary part of coordinate (quadrature).
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*/
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struct cordic_iq {
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s32 i;
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s32 q;
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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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* The function calculates the i/q coordinate for a given angle using the
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* CORDIC algorithm. The coordinate consists of a real (i) and an
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* imaginary (q) part. The real part is essentially the cosine of the
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* angle and the imaginary part is the sine of the angle. The returned
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* values are scaled by 2^16 for precision. The range for theta is
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* for -180 degrees to +180 degrees. Passed values outside this range are
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* converted before doing the actual calculation.
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*/
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struct cordic_iq cordic_calc_iq(s32 theta);
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#endif /* __CORDIC_H_ */
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