the register file contains the following registers:
0 : SP | The stack pointer is a 16-bit register for
Holding the current address of the stack.
1 : SR REG | Status register contains the following from LSB to MSB
0: (C) Carry flag
1: (Z) Zero flag
2: (N) Negative flag
3: (E) Even flag
2-3 : INPUT OUTPUT REGISTERS
4-15: GP Registers