exp3e.c

(Ebook-Pdf) Dsp - Real Time Digital Signal Processing (Usando Tms320-55Xx). 有书

/* ---------------------------------

    exp3e.c
	
    Fixed-point representaion

------------------------------------ */       

extern void sine_cos(int, int *); 

const int theta[16]={
0x9556,0xa000,0xaaab,0xc000,  /* -150, -135, -120, -90 */
0xd555,0xe000,0xeaab,0xffff,  /*  -60,  -45,  -30,  -0 */ 
0x1555,0x2000,0x2aaa,0x4000,  /*   30,   45,   60,  90 */            
0x5555,0x6000,0x6aaa,0x7fff}; /*  120,  135,  150, 180 */

int	result_buf[32];       
int Wn_buf[2];        

void main()
{    
    int *result, *Wn; 
    int i;

    for (i=0; i<32; i++)
        result_buf[i]=0;
			      
    result = result_buf;
    Wn = Wn_buf;
	                                    
    /* 3rd quadrant angles */  
    sine_cos(theta[0], Wn); /* -150 */
    *result++ = *Wn++;
    *result++ = *Wn--; 
    sine_cos(theta[1], Wn); /* -135 */
    *result++ = *Wn++;
    *result++ = *Wn--;	
    sine_cos(theta[2], Wn); /* -120 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[3], Wn); /* -90  */
    *result++ = *Wn++;
    *result++ = *Wn--;
		
    /* 4th quadrant angles */  
    sine_cos(theta[4], Wn); /* -60 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[5], Wn); /* -45 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[6], Wn); /* -30 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[7], Wn); /* -0  */
    *result++ = *Wn++;
    *result++ = *Wn--;
	
    /* 1st quadrant angles */
    sine_cos(theta[8], Wn);   /* 30 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[9], Wn);	  /* 45 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[10], Wn); /* 60 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[11], Wn); /* 90 */   
    *result++ = *Wn++;
    *result++ = *Wn--;
		
    /* 2nd quadrant angles */
    sine_cos(theta[12], Wn); /* 120 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[13], Wn); /* 135 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[14], Wn); /* 150 */
    *result++ = *Wn++;
    *result++ = *Wn--;
    sine_cos(theta[15], Wn); /* 180 */
    *result++ = *Wn++;
    *result++ = *Wn--;
}