Why is this code not working. When I run it and click the reset button it goes back to the ldr r$3,=$str line. The user button does nothing. I need it to be a $4$ bit binary counter led where I click the button and the corresponding lights light up$.$

$.$syntax unified

$.$text

$.$global main

$.$equ MODER, $0$x$00$

$.$equ AHB$1$ENR, $0$x$30$

$.$equ GPIO$\_$BSRR$,0$x$18$

$.$equ GPIOA, $0$x$40020000$

$.$equ GPIOD, $0$x$40020$C$00$

$.$equ RCC$,0$x$40023800$

$.$equ IDR, $0$x$10$

$.$equ ODR, $0$x$14$

$.$equ Blue, $0$x$8000$

$.$equ Red, $0$x$4000$

$.$equ or$,0$x$2000$

$.$equ gr$,0$x$1000$

main:

bl InitLED

bl InitButton

ldr r$3,=$Count

ldr r$4,[$r$3]$

mainloop:

bl WAIT

ldr r$4,[$r$3]$

cmp r$4,$#$15$

bgt resetCount

bl LEDonoff

bl Delay

add r$4,$r$4,$#$1$

str r$4,[$r$3]$

bl CheckButton

cmp r$0,$#$1$

beq mainloop

resetCount:

mov r$4,$#$0$

str r$4,[$r$3]$

b mainloop

WAIT:

bl CheckButton

cmp r$0,$#$1$

beq WAIT

release:

bl CheckButton

cmp r$0,$#$0$

beq release

bx lr

InitLED:

ldr r$0,=$RCC

ldr r$1,[$r$0,$ #AHB$1$ENR$]$

orr r$1,$ r$1,$ #$0$x$08$

str r$1,[$r$0,$ #AHB$1$ENR$]$

ldr r$0,=$GPIOD

ldr r$1,[$r$0,$ #MODER$]$

bic r$1,$ r$1,$ #$0$xF$0000000$

orr r$1,$ r$1,$ #$0$x$55000000$

str r$1,[$r$0,$ #MODER$]$

bx lr

InitButton:

ldr r$0,=$RCC

ldr r$1,[$r$0,$ #AHB$1$ENR$]$

orr r$1,$ r$1,$ #$0$x$01$

str r$1,[$r$0,$ #AHB$1$ENR$]$

ldr r$0,=$GPIOA

ldr r$1,[$r$0,$ #MODER$]$

bic r$1,$ r$1,$ #$0$x$00000003$

str r$1,[$r$0,$ #MODER$]$

bx lr

CheckButton:

ldr r$0,=$GPIOA

ldr r$1,[$r$0,$ #IDR$]$

and r$0,$ r$1,$ #$0$x$00000001$

bx lr

LEDonoff:

push $\{$r$0,$ r$1,$ r$2\}$

ldr r$1,=$GPIOD

ldr r$4,[$r$3]$

and r$2,$r$4,$#$0$x$0$F

mov r$0,$#$0$xF$000$

str r$0,[$r$1,$#GPIO$\_$BSRR$+4]$

lsl r$2,$r$2,$#$12$

str r$2,[$r$1,$#ODR$]$

pop $\{$r$0,$r$1,$r$2\}$

bx lr

Delay:

ldr r$2,=$#$0$x$100000$

loop:

subs r$2,$ r$2,$ #$1$

bne loop

bx lr

$.$data

Count: $.$word $0$

$.$end