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git.gir.st - tmk_keyboard.git/blob - tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_lms_init_q15.c
1 /*-----------------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
8 * Title: arm_lms_init_q15.c
10 * Description: Q15 LMS filter initialization function.
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * - Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in
21 * the documentation and/or other materials provided with the
23 * - Neither the name of ARM LIMITED nor the names of its contributors
24 * may be used to endorse or promote products derived from this
25 * software without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38 * POSSIBILITY OF SUCH DAMAGE.
39 * ---------------------------------------------------------------------------*/
44 * @ingroup groupFilters
53 * @brief Initialization function for the Q15 LMS filter.
54 * @param[in] *S points to an instance of the Q15 LMS filter structure.
55 * @param[in] numTaps number of filter coefficients.
56 * @param[in] *pCoeffs points to the coefficient buffer.
57 * @param[in] *pState points to the state buffer.
58 * @param[in] mu step size that controls filter coefficient updates.
59 * @param[in] blockSize number of samples to process.
60 * @param[in] postShift bit shift applied to coefficients.
64 * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
66 * {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
68 * The initial filter coefficients serve as a starting point for the adaptive filter.
69 * <code>pState</code> points to the array of state variables and size of array is
70 * <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of
71 * input samples processed by each call to <code>arm_lms_q15()</code>.
74 void arm_lms_init_q15(
75 arm_lms_instance_q15
* S
,
83 /* Assign filter taps */
86 /* Assign coefficient pointer */
89 /* Clear state buffer and size is always blockSize + numTaps - 1 */
90 memset(pState
, 0, (numTaps
+ (blockSize
- 1u)) * sizeof(q15_t
));
92 /* Assign state pointer */
95 /* Assign Step size value */
98 /* Assign postShift value to be applied */
99 S
->postShift
= postShift
;
104 * @} end of LMS group