fir.c

基于ICETEK-DM642-c的程序

/*
 *  Copyright 2001 by Texas Instruments Incorporated.
 *  All rights reserved. Property of Texas Instruments Incorporated.
 *  Restricted rights to use, duplicate or disclose this code are
 *  granted through contract.
 *  U.S. Patent Nos. 5,283,900  5,392,448
 */
/* "@(#) DSP/BIOS 4.51.0 05-23-01 (barracuda-i10)" */
/***************************************************************************/
/*                                                                         */
/*     V O L U M E . C                                                     */
/*                                                                         */
/*     Audio gain processing in a main loop                                */
/*                                                                         */
/***************************************************************************/

#include <stdio.h>

#include "volume.h"

/* Global declarations */
short inp_buffer[BUFSIZE];       /* processing data buffers */
short out_buffer[BUFSIZE]={0x00000000,
0x0000000f,
0x0000001e,
0x0000002d,
0x0000003a,
0x00000046,
0x00000050,
0x00000059};
short h[BUFSIZE]={1,2,3,4,5,6,7,8};

int gain = MINGAIN;                      /* volume control variable */
unsigned int processingLoad = BASELOAD;  /* processing routine load value */

struct PARMS str =
{
    2934,
    9432,
    213,
    9432,
    &str
};

/* Functions */
extern void load(unsigned int loadValue);

static int processing(short *input, short *output);
static void dataIO(void);

void fir8(short x[], short h[], short y[], int N, int M)
		{
			int i, j, sum;
			
       		    for (j = 0; j < M; j++) {
				sum = 0;
				for (i = 0; i < N; i++)
					sum += x[i + j] * h[i];
				y[j] = sum >> 15;
			}
		}

/*
 * ======== main ========
 */
void main()
{
    short *input = &inp_buffer[0];
    short *output = &out_buffer[0];
    
    puts("volume example started\n");

    /* loop forever */
    while(TRUE)
    {       
        /* 
         *  Read input data using a probe-point connected to a host file. 
         *  Write output data to a graph connected through a probe-point.
         */
        dataIO();
        #ifdef FILEIO
        puts("begin processing")        /* deliberate syntax error */
        #endif
        
        /* apply gain */
        processing(input, output);
    }
}

/*
 *  ======== processing ========
 *
 * FUNCTION: apply signal processing transform to input signal.
 *
 * PARAMETERS: address of input and output buffers.
 *
 * RETURN VALUE: TRUE.
 */
static int processing(short *input, short *output)
{
    fir8( input, &h[0],output, 8, 2);
    /* additional processing load */
    load(processingLoad);
    
    return(TRUE);
}

/*
 *  ======== dataIO ========
 *
 * FUNCTION: read input signal and write processed output signal.
 *
 * PARAMETERS: none.
 *
 * RETURN VALUE: none.
 */
static void dataIO()
{
    /* do data I/O */

    return;
}