fir_fixpt_dsplib.c

用dsp解压mp3程序的算法

/*****************************************************************
*  fir_fixpt_dsplib.c - C program for FIR filtering using DSPLIB
*                       in Section 6.6.7
******************************************************************
*  System configuration:
*
* 
* in(n) |----------------| out(n)
*  ---->| Bandpass filter|----->
*       |----------------|
*
******************************************************************
*  System simulation configuration:
*
*     in_buffer is used to store the input data
*     out_buffer is used to store the output filtered data
*
*****************************************************************/

#include "math.h"
#include "tms320.h"
#include "dsplib.h"

#include "input.h"		    // input signal file
#include "coeff_ccs_16int_lib.h" 

short i;
DATA  *dbptr = &db[0];

ushort oflag;
#pragma DATA_SECTION(NUM,".coeffs") 
void main(void)
{
    asm(" STM	#0, SWWSR");

    /* clear */
    for (i=0; i<NX; i++) r[i] = 0;  // clear output buffer (optional)
    for (i=0; i<NL; i++) db[i] = 0; // clear delay buffer (a must)

    /* compute */

    oflag = fir(x, NUM, r, &dbptr, NL, NX);  

    /* (ii) 75 samples/block */ 
    /*if (NX >= 4)
    {
        fir(x,NUM,r,&dbptr,NL,NX/4);
        fir(&x[NX/4],NUM,&r[NX/4],&dbptr,NL,NX/4);
        fir(&x[NX/2],NUM,&r[NX/2],&dbptr,NL,NX/4);
        fir(&x[(3*NX)/4],NUM,&r[(3*NX)/4],&dbptr,NL,NX/4);
    } */  

    /* (iii) sample mode  */
    /*for (i=0; i<NX; i++)
    {
        fir(&x[i],NUM,&r[i],&dbptr,NL,1);
    } */ 

    return;
}