Overall Configuration of the CPU: PSW (Flag)

After executing the instruction, a flag indicates the contents of the memory and the status of the result of a calculation.
PSW (*) collects these flags.

* PSW：Program Status Word

The figure on the right is an example of executing the addition of the A register (00111110) and the B register (11100000).
The calculation result (100011110) is stored in the A register.
However, since the A register can store only 8 bits, the carry flag is set to "1" and the carry flag is left as information that a carry has occurred.
In the A register, (00011110) excluding the most significant digit 1 is stored as the calculation result.
For example, if the calculation result is (100000000), 1 is set in the carry flag, and (00000000) is stored in the A register, so 1 is set in the zero flag.