;* ======================================================================== *;
;*  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.                           *
* ========================================================================= *