reset:
br always >main
nop

hardfault:
reti
nop

memfault:
reti
nop

irq3:      
br always >irq3_handler
nop

.align
addr:
.word 0x000F0000
addrsw:
.word 0x000F0006
//w_cnt_top:	.word 0x1FC000
w_cnt_top:	.word 0x1		//for simulation only

// Constant Declaration
.align
sp_init:   .word 0x400 // Stackpointer Initial Value


main:
ldr r12, >sp_init
clr r14
ldr r0,>addr	//LED addr
ldr r2,>addrsw	//sw addr
addi r6,8		//outer counter top
clr r7			//wait counter

here:
nop
nop
nop
br always >here
nop

out_loop:
ldr r8,>w_cnt_top
clr r1
st08 r0,r1
call >wait
nop

fill:
	lsh r1,r1,1
	addi r1,1
	st08 r0,r1
	call >wait
	nop

	addi r5,1
	cmp neq r5,r6
	br true >fill
	nop
	clr r5

flush:
	lsh r1,r1,1
	st08 r0,r1
	call >wait
	nop

	addi r5,1
	cmp neq r5,r6
	br true >flush
	nop
	clr r5
	br always >out_loop
	nop

//subroutine to iterate until counter overflow
wait:
	clr r3
	ld16 r3,r2 //loading switches content to r3 from r2 address	
	clr r9
	clr r10
	clr r11
	br always >nfound
	nop
found:	rsh r8,r8,1 //one found
nfound:	clr r4
	addi r4,1
	addi r10,1 //loop counter max 16
	and r9,r3,r4
	cmp eq r9,r4
	br true >found
	rsh r3,r3,1
	clr r4
	addi r4,16
	cmp le r10,r4
	br true >nfound
	nop

	clr r7				//inititalize inner counter
	inc_i:
	cmp neq r7,r8
	br true >inc_i		//if i=cnt_top
	addi r7,1
	ret					//else
	nop



irq3_handler: 





br always >out_loop
nop
reti