ARM assembly language

Make the first green LED turn on when the first button is pressed and turn off when the button is pressed again. The LED should not change state when the button is released or if the button is held down?

I'm not sure how to write code for this question, here is what i understand so far. Right now I press the button the light is on but it's off when i release the button

.text .global main

.equ LED, 0x41210000 .set BT, 0x41200000

main: ldr r1,=BT ldr r2,=LED loop_1: ldr r0,[r1] cmp r0,#1 beq led_light_1 mov r3 led_dim: mov r0,#0 str r0,[r2] b loop_1 @go back to start of loop

led_light_1: mov r0,#1 str r0,[r2] b loop_1