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118 lines
8.7 KiB
118 lines
8.7 KiB
;* ======================================================================== *;
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;* TEXAS INSTRUMENTS, INC. *;
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;* *;
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;* DSPLIB DSP Signal Processing Library *;
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;* *;
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;* Release: Revision 1.04b *;
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;* CVS Revision: 1.9 Sun Sep 29 03:32:22 2002 (UTC) *;
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;* Snapshot date: 23-Oct-2003 *;
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;* *;
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;* This library contains proprietary intellectual property of Texas *;
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;* Instruments, Inc. The library and its source code are protected by *;
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;* various copyrights, and portions may also be protected by patents or *;
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;* other legal protections. *;
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;* *;
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;* This software is licensed for use with Texas Instruments TMS320 *;
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;* family DSPs. This license was provided to you prior to installing *;
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;* the software. You may review this license by consulting the file *;
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;* TI_license.PDF which accompanies the files in this library. *;
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;* ------------------------------------------------------------------------ *;
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;* Copyright (C) 2003 Texas Instruments, Incorporated. *;
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;* All Rights Reserved. *;
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;* ======================================================================== *;
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;* ======================================================================== *;
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;* Assembler compatibility shim for assembling 4.30 and later code on *;
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;* tools prior to 4.30. *;
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;* ======================================================================== *;
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;* ======================================================================== *;
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;* End of assembler compatibility shim. *;
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;* ======================================================================== *;
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* ======================================================================== *
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* NAME *
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* DSP_firlms2 -- Least Mean Square Adaptive Filter *
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* Hand Coded Assembly Implementation *
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* *
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* REVISION DATE *
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* 13-Mar-2002 *
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* *
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* USAGE *
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* *
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* This routine has the following C prototype: *
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* *
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* long DSP_firlms2 *
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* ( *
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* short *restrict h, // Filter Coefficients *
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* const short *restrict x, // Input Data *
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* short b, // Error from previous FIR *
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* int nh // Number of Coefficients *
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* ) *
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* *
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* The DSP_firlms2 routine accepts a list of 'nh' input data and 'nh' *
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* adaptive filter coefficients and updates the coefficients by *
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* adding weighted error times the inputs to the original *
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* coefficients. This assumes single sample input followed by the *
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* last nh-1 inputs and nh coefficients. *
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* *
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* DESCRIPTION *
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* *
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* The algorithm is simple and Natural C implementation is as follows: *
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* *
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* long DSP_firlms2 *
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* ( *
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* short *restrict h, // Filter Coefficients *
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* const short *restrict x, // Input Data *
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* short b, // Error from previous FIR *
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* int nh // Number of Coefficients *
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* ) *
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* { *
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* int i; *
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* long r=0; *
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* *
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* for(i = 0; i < nh; i++) *
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* { *
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* * Update the filter coefficients * *
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* *
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* h[i] += (x[i] * b) >> 15; *
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* *
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* * Calculate the filter output * *
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* *
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* r += x[i + 1] * h[i]; *
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* } *
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* return r; *
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* } *
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* *
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* TECHNIQUES *
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* - The loop is unrolled 4 times *
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* - MPY2, PACKH2 and ADD2 are used to update the filter coefficients *
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* - DOTP2 is used to calculate filter output *
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* *
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* ASSUMPTIONS *
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* - Assumes 16-bit input data, error and filter coefficients. *
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* - nh > = 4 and is a multiple of 4 *
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* *
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* MEMORY NOTE *
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* *
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* NOTES *
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* - Little Endian *
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* - No Bank Conflict *
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* - interrupt tolerant but not interruptible *
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* *
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* CYCLES *
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* 3 * nh/4 + 17 *
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* *
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* CODESIZE *
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* 144 bytes *
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* *
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* ------------------------------------------------------------------------ *
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* Copyright (c) 2003 Texas Instruments, Incorporated. *
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* All Rights Reserved. *
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* ======================================================================== *
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.global _DSP_firlms2
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* ========================================================================= *
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* End of file: dsp_firlms2.h64 *
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* ------------------------------------------------------------------------- *
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* Copyright (c) 2003 Texas Instruments, Incorporated. *
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* All Rights Reserved. *
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* ========================================================================= *
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