;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  DSPLIB  DSP Signal Processing Library                                   *;
;*                                                                          *;
;*      Release:        Version 1.02                                        *;
;*      CVS Revision:   1.4     Fri Mar 29 21:10:31 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_w_vec: Weighted vector sum                                      *
*                                                                           *
*                                                                           *
*   REVISION DATE                                                           *
*       29-Mar-2002                                                         *
*                                                                           *
*   USAGE                                                                   *
*       This routine is C-callable and can be called as:                    *
*                                                                           *
*           void DSP_w_vec                                                  *
*           (                                                               *
*               const short *x,     /* Vector being weighted  */            *
*               const short *y,     /* Non-weighted vector    */            *
*               short m,            /* weighting factor       */            *
*               short *restrict r,  /* Result vector          */            *
*               int nr              /* Number of samples.     */            *
*           );                                                              *
*                                                                           *
*   DESCRIPTION                                                             *
*       The benchmark performs a weighted vector sum.  The elements         *
*       of the x[] vector are weighted according to the Q15 value 'm',      *
*       and then added to the corresponding elements of the y[] vector.     *
*       The results are written to the r[] vector.                          *
*                                                                           *
*   C CODE                                                                  *
*       The following is a C code description of the algorithm.  This       *
*       implementation may have restrictions, as noted under                *
*       "ASSUMPTIONS" below.                                                *
*                                                                           *
*           void DSP_w_vec                                                  *
*           (                                                               *
*               const short *x,     /* Vector being weighted  */            *
*               const short *y,     /* Non-weighted vector    */            *
*               short m,            /* weighting factor       */            *
*               short *restrict r,  /* Result vector          */            *
*               int nr              /* Number of samples.     */            *
*           )                                                               *
*           {                                                               *
*               int i;                                                      *
*                                                                           *
*               for (i = 0; i < nr; i++)                                    *
*                   r[i] = ((m * x[i]) >> 15) + y[i];                       *
*           }                                                               *
*                                                                           *
*   ASSUMPTIONS                                                             *
*       m is not -32768.                                                    *
*       nr >= 4, nr is multiple of four.                                    *
*       Input and output arrays must be word aligned.                       *
*                                                                           *
*   MEMORY NOTE                                                             *
*       No bank conflicts occur.                                            *
*       This code is endian neutral.                                        *
*                                                                           *
*   TECHNIQUES                                                              *
*       This loop is unrolled 4x to make full use of the available          *
*       memory bandwidth.                                                   *
*                                                                           *
*       SMPY is used in conjunction with shifts and masks so that the       *
*       m * x[i] terms may be packed pairs within 32-bit registers.  This   *
*       allows us to use packed-data processing for the rest of the         *
*       algorithm, thereby maximizing our load/store bandwidth.             *
*                                                                           *
*   NOTES                                                                   *
*       This code is interrupt tolerant but not interruptible.              *
*                                                                           *
*   CYCLES                                                                  *
*       3*nr/4 + 19                                                         *
*       For nr = 256,  cycles = 211.                                        *
*       For nr = 1000, cycles = 770.                                        *
*                                                                           *
*   CODESIZE                                                                *
*       192 bytes                                                           *
*                                                                           *
*   SOURCE                                                                  *
*       DSPLIB.                                                             *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2002 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *

        .global _DSP_w_vec

* ========================================================================= *
*   End of file:  dsp_w_vec.h62                                             *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2002 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *