;* ======================================================================== *;
;* TEXAS INSTRUMENTS, INC. *;
;* *;
;* DSPLIB DSP Signal Processing Library *;
;* *;
;* Release: Version 1.02 *;
;* CVS Revision: 1.5 Sun Mar 17 11:25:23 2002 (UTC) *;
;* Snapshot date: 18-Apr-2002 *;
;* *;
;* This library contains proprietary intellectual property of Texas *;
;* Instruments, Inc. The library and its source code are protected by *;
;* various copyrights, and portions may also be protected by patents or *;
;* other legal protections. *;
;* *;
;* This software is licensed for use with Texas Instruments TMS320 *;
;* family DSPs. This license was provided to you prior to installing *;
;* the software. You may review this license by consulting the file *;
;* TI_license.PDF which accompanies the files in this library. *;
;* ------------------------------------------------------------------------ *;
;* Copyright (C) 2002 Texas Instruments, Incorporated. *;
;* All Rights Reserved. *;
;* ======================================================================== *;
* ========================================================================= *
* *
* TEXAS INSTRUMENTS, INC. *
* *
* NAME *
* DSP_fir_gen *
* *
* REVISION DATE *
* 15-Feb-2002 *
* *
* USAGE *
* This routine is C-callable and can be called as: *
* *
* void DSP_fir_gen *
* ( *
* const short *restrict x, *
* const short *restrict h, *
* short *restrict r, *
* int nh, *
* int nr *
* ) *
* *
* x[nr+nh-1] : Input array *
* h[nh] : Coefficient array. Must be in reverse order. *
* r[nr] : Output array *
* nh : Number of coefficients. Must be >= 5. *
* nr : Number of output samples *
* *
* DESCRIPTION *
* Computes a real FIR filter (direct-form) using coefficients stored *
* in vector h. The coefficients have to be arranged in reverse *
* order. The real data input is stored in vector x. The filter *
* output result is stored in vector r. It operates on 16-bit data *
* with a 32-bit accumulate. The filter is nr output samples and nh *
* coefficients. *
* *
* C CODE *
* void DSP_fir_gen *
* ( *
* const short *restrict x, *
* const short *restrict h, *
* short *restrict r, *
* int nh, *
* int nr *
* ) *
* { *
* int i, j, sum; *
* *
* for (j = 0; j < nr; j++) *
* { *
* sum = 0; *
* for (i = 0; i < nh; i++) *
* sum += x[i + j] * h[i]; *
* r[j] = sum >> 15; *
* } *
* } *
* *
* TECHNIQUES *
* The inner loop is unrolled four times, but the last three *
* accumulates are executed conditionally to allow for a number of *
* coefficients that is not a multiple of four. The outer loop is *
* unrolled twice, but the last store is executed conditionally to *
* allow for a number of output samples that is not a multiple of *
* two. Both the inner and outer loops are software pipelined. *
* *
* ASSUMPTIONS *
* nh must be >= 5. *
* *
* MEMORY NOTE *
* No memory bank hits under any conditions. *
* *
* NOTES *
* This function is interrupt-tolerant but not interruptible. *
* This function is endian neutral. *
* *
* CYCLES *
* (4 * ceil(nh/4) + 9) * ceil(nr/2) + 18 *
* *
* For nh = 13, nr = 19: 268 cycles *
* *
* CODESIZE *
* 640 bytes *
* *
* ------------------------------------------------------------------------- *
* Copyright (c) 2002 Texas Instruments, Incorporated. *
* All Rights Reserved. *
* ========================================================================= *
.global _DSP_fir_gen
* ========================================================================= *
* End of file: dsp_fir_gen.h62 *
* ------------------------------------------------------------------------- *
* Copyright (c) 2002 Texas Instruments, Incorporated. *
* All Rights Reserved. *
* ========================================================================= *