ale_fixpt_c55x.c

用dsp解压mp3程序的算法

/*****************************************************************
*  ale_fixpt_c55x.c - Fixed-point C program for ALE on C5000 CCS
*                     using C55x assembly routines
******************************************************************
*  System configuration:
*
* d(n) ---------------------------
*     |             /             |
* d(n-1)|----------------| out(n) V
*  ---->| ALE (LMS-FIR)  |-----> |+|------>
*       |----------------|     -       | 
*             /________________________|
*
*
*     d(n) is the input data from data file "in_int_ccs.dat"
*
*****************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int in_buffer[500];                           
int out_buffer[500];
int err_buffer[500]; 
#define TRUE 1

/*    Functions used in this programs    */

extern void shift_c55x(int *,int , int );  
extern void adapt_c55x(int *,int *,int *,int ,int ,int * );
static int aleproc(int *input, int *output, int *error);
static void dataIO(void);

void main()
{
  /***************************************************************
  *    Declare file pointers
  ***************************************************************/
  int *input = &in_buffer[0];
  int *output= &out_buffer[0];
  int *error= &err_buffer[0]; 
  
  /***************************************************************
  *    Start of main program
  ***************************************************************/
 
  while(TRUE)
  {           /* read in x(n) from data file and processing it  */   
    dataIO();
    aleproc(input, output, error);  
  }
}


/*    Function aleproc for ALE processing                       */

static int aleproc(int *input, int *output, int *error)
{
  /***************************************************************
  *    Define variable arrays, define and clear variables
  ***************************************************************/
  #define NL 16		 /* length of FIR filter                */
  int yn = 0;            /* y(n), output from the filter        */
  int xnbuf[16+1];       /* extra memory location for the shift */
  int w[16];  
  int k;
  int mu = 1000;	 /* 33(0.001); 338(0.01); 655(0.02)     */
  int err;
  int dn = 0;
  int size = 500;
  
  /***************************************************************
  *    Start of main program
  ***************************************************************/
  for(k=0; k<NL; k++)
  {
    xnbuf[k]=0;
    w[k] = 0;
  }
  
  while(size--)
  {     	     			
    /*************************************************************
    *    FIR filtering:
    *         y(n) = sum[x(n-i)*w(i)] for i = 0 to NL-1
    *************************************************************/
    shift_c55x(xnbuf,NL/2,dn);  /* refresh signal buffer        */
    dn = *input++; 
    err = dn-yn;                /* compute e(n-1)               */     
    adapt_c55x(&err,xnbuf,w,NL,mu,&yn); /* FIR filtering and the
                                           LMS updating         */
    *output++ = yn;	
    *error++  = err; 
  }
  return(TRUE);
}


/*    Function for dataIO    */

static void dataIO()
{
  return;
}