Button presses

Give it some time between button presses. Say, half a second or a second.

Be aware of the space rules!

Make sure to follow the rules:
Labels should always be flush to the left.
Comments can be flush to the left or have spaces from the left
Every other statement should at least have a space or a tab from the left; this includes the lines that start with a dot, like .data, .text etc. as well as all the assembly statements.