/* ///////////////////////////////////////////////////////////////////////////////////
/    talkthru.asm                                                                    /
/                                                                                    /
/    Receives input from the AD1836 internal ADCs via the ADSP-21161 serial port     /
/    (SPORT0), and transmits the data back to the AD1836 internal DACs (SPORT2).     /
/                                                                                    /
/    The samples from the AD1836 are 24 bit and are left-justified in the upper      /
/    24-bits of the the 32-bit word (timeslot).  No shifting of the data is required /
/    in order to preserve the sign of the samples when they are converted to         /
/    floating point numbers, as the audio data is already in the assumed 1.31 format./
/    The values are also scaled to the range +/-1.0  with the integer to float       /
/    conversion (f0 = float r0 by r1).                                               /
/////////////////////////////////////////////////////////////////////////////////// */

/* ADSP-21161 System Register bit definitions */
#include "def21161.h"

#define HEADPHONE -0			// use this when using headphone output jack (connected to AD1836 DAC0)
#define DAC0_RCA_JACK -0		// use thes definition in shifter instruction when using RCA outputs

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

.section /pm pm_code;

//.GLOBAL	 	Play_Song;
//.GLOBAL		Auto_Double_Tracking;

.GLOBAL		process_audio;
//.GLOBAL		user_code_init;


.EXTERN		Auto_Double_Tracking;


.EXTERN		Left_Channel_Out0;
.EXTERN		Right_Channel_Out0;
.EXTERN		Left_Channel_Out1;
.EXTERN		Right_Channel_Out1;


.EXTERN		Left_Channel;
.EXTERN		Right_Channel;

.EXTERN		Play_Song;
.EXTERN 	chorus_effect;
//.EXTERN		user_code_init;




process_audio:
	call Play_Song;						/* generate song via sine wave generation routine */

	DM(Left_Channel_Out1) = r8; 		/* send non-postprocessed left channel result to AD1836 Left DAC1 */
	DM(Right_Channel_Out1) = r8;		/* send non-postprocessed right channel result to AD1836 Right DAC1 */

	if FLAG1_in jump skip_ADT_effect;	/* pressing FLAG1 bypasses chorus and delay effects */

do_audio_post_processing:
	if FLAG3_IN jump skip_chorus_processing;  /* pressing FLAG3 pushbutton will bypass Stereo Chorus Effect */
	call (pc, chorus_effect); 

skip_chorus_processing:
	if FLAG2_IN jump skip_ADT_effect;	
	call Auto_Double_Tracking; 

skip_ADT_effect:
	r0 = DM(Left_Channel);	r2 = DM(Right_Channel);
	r0 = ASHIFT r0 by HEADPHONE;		/* turn down the volume for headphone jack */
	r2 = ASHIFT r2 by HEADPHONE;		/* turn down the volume for headphone jack */
	DM(Left_Channel_Out0) = r0; 		/* send left channel result to AD1836 Left DAC0 */
	DM(Right_Channel_Out0) = r2;		/* send right channel result to AD1836 Right DAC0 */

done_processing:
	rts;

process_audio.end: