When is entered, it is picked up by the scanning unit; the number 25 is encoded and sent to the X register; Next, when the key is pressed, the "addition" instruction is also encoded and sent to the flag or the status register; The second number is encoded and sent to the X register. This "pushes" (shifts) the first number out into the Y register; When the key is pressed, a "message" (signal) from the flag or status register tells the permanent or non-volatile memory that the operation to be done is "addition"; The numbers in the X and Y registers are then loaded into the ALU and the calculation is carried out following instructions from the permanent or non-volatile memory; The answer, 34 is sent (shifted) back to the X register. From there, it is converted by the binary decoder unit into a decimal number (usually binary-coded decimal), and then shown on the display panel.
When is entered, it is picked up by the scanning unit;, the number 25 is encoded and sent to the X register; Next, when the key is pressed, the "addition" instruction is also encoded and sent to the flag or the status register; The second number is encoded and sent to the X register. This "pushes" (shifts) the first number out into the Y register; When the key is pressed, a "message" (signal) from the flag or status register tells the permanent or non-volatile memory that the operation to be done is "addition"; The numbers in the X and Y registers are then loaded into the ALU and the calculation is carried out following instructions from the permanent or non-volatile memory; The answer 34 is sent (shifted) back to the X register. From there, it is converted by the binary decoder unit into a decimal number (usually binary-coded decimal), and then shown on the display panel.