.copy "v:\ece320\54x\dsplib\core.asm"



	;WAH AUDIO EFFECT CODE

	;ECE320 DSP LAB (SPRING 2001)

	;PIYA POONGBUNKOR AND VICERUT NONZEE



    .sect ".data" 



BRChold		.word 23		; set word for BRC vlue

begin		.word 0			; set word for counter start value

finish		.word 11000		; set word for counter end value

delay		.word 512        	; set word for delay length

NUMBYTES .set   1			; set NUMBYTES = 1

	.sect ".data"

data_buf

	.space NUMBYTES*16		; allocate NUMBYTES words for 

					;    serial data buffer

data_ptr

	.word   data_buf		; data_ptr initialized to store address

					;    of first word in serial data buffer                        

	.sect ".text"  

main

	; initialize here

	stm		#delay,AR2	; initialize delay length in AR2

	stm		#begin,AR4	; initialize counter start in AR4

	stm		#finish,AR5	; initialize counter end in AR5



loop                    

; Wait for a new block of 64 samples to come in

	WAITDATA	

; BlockLen = the number of samples that come from WAITDATA (64)

	stm 		#BlockLen-1, BRC

	rptb 		copy-1

	mvmd		BRC,*(BRChold)





lfocounter  

	addm		#1,*AR4		; add 1 into counter address

	mvmm		AR0,AR1		; move AR0 to AR1 for safe keeping

	ld		*AR4,B		; load counter value into B

	stl		B,AR0		; store counter value into AR0

	nop				; allow cycles for store to take place

	nop

	nop    

	cmpr		0,AR5		; compare counter to desired ending value

	mvmm		AR1,AR0		; move AR1 back to AR0 

	bc		check,TC	; branch if counter reachs desired value

	b		jump		; else branch to jump



check  

	stm		#begin,AR4	; reset counter to LFO counter to 0 

	mvmm		AR0,AR1		; move AR0 to AR1 for safe keeping

        stm		#0x20,AR0	; store 32 to AR0 (lower boundary)

	nop				; allow cycles for store to take place

	nop

	nop

    	cmpr		1,AR2		; compare if less than 32

	mvmm		AR1,AR0		; move AR1 back to AR0 

	bc		lfoup,TC	; if less than branch to lfoup

	stm		#0x200,AR0	; store 512 to AR0 (upper boundary)

	nop				; allow cycles for store to take place

	nop

	nop

	cmpr		2,AR2		; compare if greater than 512

	mvmm		AR1,AR0		; move AR1 back to AR0

	bc		lfodwn,TC	; if greater than branch to lfodwn

lfodwn 					; decrements delay length

	ldm		AR2,B		; load delay lendth into B

	sub		#0x30,B		; subtract B by 48

	stl		B,AR2		; store low part of B into AR2

	b		jump 		; branch to jump (output)

lfoup					; increments delay length

	ldm		AR2,B		; load delay lendth into B

	add		#0x30,B		; add 48 to B

	stl		B,AR2		; store low part of B into AR2

	b		jump 		; branch to jump

jump  

   	ld      	*AR6+,16,B	; load input to accum B

   	mvmm		AR6,AR1  	; move value of AR6 to AR1

  	mar		*+AR6(4)	; input on all other channels

  	WRITPROG	1   		; write to extended memory 

  	add		#1,A 		; add 1 to A (delay counter)

  	mvmm		AR0,AR1 	; move AR1 back to AR0 

 	stl		A,AR0		; store low part of A into AR0

 	nop

	nop

	nop

 	cmpr		00,AR2		; compare if AR0 = AR2

 	mvmm		AR1,AR0		; move AR1 back to AR0

    	bc		output,NTC	; branc to output if not equal

    	ld		#0x0,A		; if equal then reset delay counter to 0



output                		                             

; output samples

        mvmm		AR3,AR1         ; move value of AR3 to AR1 to read delayed values

       	READPROG	1 		; read from extended memory

    	add		*AR3,16,B       ; input + delayed input	

       	sth		B,*AR7	        ; output final

        mar		*+AR7(6)        ; output on all other channels



copy:



_serial_stuff				; this block must only run once

					;    per WAITDATA call



        pshm    AR3			; we save AR3 so you don't have to

        mvdm    data_ptr, AR3		; set AR3 to point to last byte stored 

					;    in the serial data buffer



        pshm    AR0			; we save AR0 so you don't have to

        stm     #data_buf+NUMBYTES, AR0	; #data_buf+NUMBYTES is the address of 

					;    the last word in the 

					;    serial data buffer

     

	nop

        cmpr    eq, AR3			; if last byte stored is at the last

        nop				;    address in the serial data buffer,

        nop				;    wrap to beginning of serial data

        xc      2, TC			;    buffer

	stm	#data_buf, AR3

	

	 

        READSER 1			; copy one byte from ser_rxbuf to 

					;    serial data buffer

        				;    (ser_rxbuf initialized in core file

					;     and filled automatically when 

					;     data arrives on serial port)



        mvmd    AR3, data_ptr		; save address of last byte stored 

					;    in serial data buffer

        popm    AR0			; we restore AR0 so you don't have to

        popm    AR3			; we restore AR3 so you don't have to



	mvdm	data_ptr,AR5		; move data for flanging sweeping time into AR5

		 

	b 	loop