PRESERVE8
	THUMB   
		

; ====================== zone de réservation de données,  ======================================
;Section RAM (read only) :
	area    mesdata,data,readonly


;Section RAM (read write):
	area    maram,data,readwrite
		
SortieSon dcw 0
index dcd 0
	
; ===============================================================================================
	

	EXPORT CallbackSon ;
	EXTERN bruitverre ;
	EXTERN Son ;
	EXTERN LongueurSon ;
	EXPORT SortieSon ; //pour evaluer la variable lors des tests
	
		
;Section ROM code (read only) :		
	area    moncode,code,readonly
; écrire le code ici		
CallbackSon
	ldr r1, =index
	ldr r2, [r1]
	ldr r3, =Son
	ldr r0, LongueurSon
	
	cmp r2, r0
	ble notEqual
	
	bx lr
	
notEqual
	mov r0, #2
	mul r0, r2
	ldrsh r0, [r3, r0]
	add r0, #32768
	push {r4}
	mov r4, #719
	mul r0, r4
	mov r4, #65535
	udiv r0, r4
	pop {r4}
	push {r7}
	ldr r7, =SortieSon
	str r0, [r7]
	pop {r7}
	
	add r2, #1
	push {r5}
	ldr r5, =index
	str r2, [r5]
		
	pop {r5}
	
	bx lr
	
END