title: ARM: Why only 12 bits for immediate constants?
body: <p>what does it mean : I have only 12 bits for immediate constants, so can I represent immediate constants only from 0 to 2^12  = 4096 ? Operand 2 , if it's a register, can have 32 bits, but why only 12 bits for immediate constants? Where does this number come from?</p>