dsp_minerror.h64

来自「dm642函数库」· H64 代码 · 共 132 行

;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  DSPLIB  DSP Signal Processing Library                                   *;
;*                                                                          *;
;*      Release:        Revision 1.04b                                      *;
;*      CVS Revision:   1.8     Sun Sep 29 03:32:25 2002 (UTC)              *;
;*      Snapshot date:  23-Oct-2003                                         *;
;*                                                                          *;
;*  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) 2003 Texas Instruments, Incorporated.             *;
;*                          All Rights Reserved.                            *;
;* ======================================================================== *;
;* ======================================================================== *;
;*  Assembler compatibility shim for assembling 4.30 and later code on      *;
;*  tools prior to 4.30.                                                    *;
;* ======================================================================== *;
;* ======================================================================== *;
;*  End of assembler compatibility shim.                                    *;
;* ======================================================================== *;
* ========================================================================= *
*                                                                           *
*   TEXAS INSTRUMENTS, INC.                                                 *
*                                                                           *
*   NAME                                                                    *
*       DSP_minerror -- Minimum Energy Error Search                         *
*                                                                           *
*   REVISION DATE                                                           *
*       11-Feb-2002                                                         *
*                                                                           *
*   USAGE                                                                   *
*       This routine is C-callable and can be called as:                    *
*                                                                           *
*       int DSP_minerror                                                    *
*       (                                                                   *
*           const short *restrict GSP0_TABLE,                               *
*           const short *restrict errCoefs,                                 *
*           int         *restrict max_index                                 *
*       );                                                                  *
*                                                                           *
*       GSP0_TABLE[256*9] :  Pointer to GSP0 terms array.                   *
*                            Must be double-word aligned.                   *
*       errCoefs[9]       :  Array of error coefficients.                   *
*       max_index         :  Index to GSP0_TABLE[max_index], the first      *
*                            element of the 9-element vector that resulted  *
*                            in the maximum dot product.                    *
*       return int        :  Maximum dot product result.                    *
*                                                                           *
*   DESCRIPTION                                                             *
*       Performs a dot product on 256 pairs of 9 element vectors and        *
*       searches for the pair of vectors which produces the maximum dot     *
*       product result. This is a large part of the VSELP vocoder codebook  *
*       search.                                                             *
*                                                                           *
*   C CODE                                                                  *
*       This is the C equivalent of the assembly code without restrictions  *
*       Note that the assembly code is hand optimized and restrictions may  *
*       apply.                                                              *
*                                                                           *
*       int DSP_minerror                                                    *
*       (                                                                   *
*           const short *restrict GSP0_TABLE,                               *
*           const short *restrict errCoefs,                                 *
*           int         *restrict max_index                                 *
*       )                                                                   *
*       {                                                                   *
*           int val, maxVal = -50;                                          *
*           int i, j;                                                       *
*                                                                           *
*           for (i = 0; i < GSP0_NUM; i++)                                  *
*           {                                                               *
*               for (val = 0, j = 0; j < GSP0_TERMS; j++)                   *
*                   val += GSP0_TABLE[i*GSP0_TERMS+j] * errCoefs[j];        *
*                                                                           *
*               if (val > maxVal)                                           *
*               {                                                           *
*                   maxVal = val;                                           *
*                   *max_index = i*GSP0_TERMS;                              *
*               }                                                           *
*           }                                                               *
*                                                                           *
*           return (maxVal);                                                *
*       }                                                                   *
*                                                                           *
*   TECHNIQUES                                                              *
*       Load double word instruction is used to simultaneously              *
*       load four values in a single clock cycle.                           *
*       The jloop is totally unrolled                                       *
*       The iloop is unrolled 4 times                                       *
*       A flag is used to set the exit program location                     *
*       The MV is used to move the data                                     *
*       The loop is software pipelined.                                     *
*                                                                           *
*   ASSUMPTIONS                                                             *
*       Array GSP0_TABLE[] must be double-word aligned.                     *
*                                                                           *
*   MEMORY NOTE                                                             *
*       No memory bank hits under any conditions.                           *
*                                                                           *
*   NOTES                                                                   *
*       This code is LITTLE ENDIAN.                                         *
*       This code is interrupt-tolerant but not interruptible.              *
*                                                                           *
*   CYCLES                                                                  *
*      256/4 * 9 + 17 = 593                                                 *
*                                                                           *
*   CODESIZE                                                                *
*       352 bytes                                                           *
*                                                                           *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *

        .global _DSP_minerror

* ========================================================================= *
*   End of file:  dsp_minerror.h64                                          *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *