- LOADING THE STACK WITH CONST LOADING THE STACK WITH A CONSTANT Because the number in the T-register is replicated when the stack drops, this number can be used as a constant in arithmetic operations. T c c <---New constant generation. Z c c Y c c <---Drops to interact with X-register. X x cx Keys: * Fill the stack with a constant by keying it into the display and pressing ENTER three times. Key in your initial argument and perform the arithmetic operation. The stack will drop, a copy of the constant will "fall" into the Y-register, and a new copy of the constant will be generated in the T-register.