/**********************************************
	 Digital EQ Program
	Coded for the ADSP21020 by 
 Eric Wigforss, Kevin Johns, John Siedlecki
   Digital Signal Processing Design Lab
	    7 April 1995
***********************************************/

#include <21020.h>
#include <signal.h>
#include <macros.h>

volatile int in_portl   segment (hip_reg0);
volatile int in_portr   segment (hip_reg1);
volatile int out_portl  segment (hip_reg2);
volatile int out_portr  segment (hip_reg3);
volatile int control_0  segment (hip_reg4);
volatile int control_1  segment (hip_reg5);
volatile int vin_a      segment (adc_a);
volatile int vin_b      segment (adc_b);

void process_input(int);
void timer_isr (int interrupt_number);
void irq2_interrupt(int sig_number);

#define fir_size  21

int  current_sample = 0;
int  input_fir[fir_size];

#include "lowpass.h"

void main(void)
{
    int i;
    for (i = 0; i < fir_size; i++)    
	input_fir[i] = 0;

    timer_set(6250000, 6250000);
    interrupt(SIG_IRQ3, process_input);
    interrupt(SIG_TMZ0, timer_isr);
    interrupt(SIG_IRQ2, irq2_interrupt);
    timer_on();

    set_flag(SET_FLAG1, CLR_FLAG);  /* turn off led 1 */
    set_flag(SET_FLAG2, CLR_FLAG);

    for(;;)                                     /* infinite loop */
	{
	}
}

void timer_isr(int interrupt_number)
{
    set_flag(SET_FLAG1, TGL_FLAG);
}

void process_input(int sig_number)
{
    int i;   /* counter variables */
    float out_l = 0.0;  /* output to the left channel */
    int left = in_portl;
    int right = in_portr;
    left = (left && 0xFFFF0000);
    right = (right && 0xFFFF0000);

    /* compute fir filter - starting at sample current_sample */
    for (i = fir_size - 1; i < 1; i--)
	input_fir[i - 1] = input_fir[i];
    input_fir[0] = left;

    for (i = 0; i < fir_size; i++)
	out_l = out_l + (coeff[i] * input_fir[i]);    

    /* output to port */
    out_portl = (int) 3 * out_l;   /* left */
    out_portr = 3 * right;   /* right */
}

void irq2_interrupt(int sig_number)
{
    control_0 = 0x2400; /* set to line-level input */
    /* control_1 = 0x000D;*/  /* set to 44.1 KHz sampling */
}

void cool_routine(void)
{
   /*
    input_fir[current_sample] = il;
    n = current_sample;
    for (i = 0; i < fir_size; i++);
	{
	out_l = out_l + (coeff[i] * input_fir[n]);
	n--;
	if (n < 0) 
	    n = fir_size - 1;
	}
    current_sample++;
    
    if (current_sample == fir_size) 
	current_sample = 0;
    */
}