• 16 bit address
• 8 bit data
• can write address to the bus
• can read and write data to the bus
• 56 legal instructions
• each instruction has a size and duration(clock cycles)

• LDA $41 2-BYTE (IMMEDIATE ADDRESSING MODE) [ OPERAND OPCODE ]
• LDA $0105 3-BYTE ( ABSOLUTE ADDRESSING )
• CLC 1-BYTE

For a given instruction we need to implement the function + addressing mode + cycles

• [ 8 BIT ] A (accumulator)
• [ 8 BIT ] X
• [ 8 BIT ] Y
• [ 8 BIT ] stkp STACK POINTER
• [ 16 BIT ] pc PROGRAM COUNTER ( contains the next byte of instruction )
• [ 8 BIT ] status STATUS REGISTER ( check for various operations like carry, enable/disable interrupts and zero compare )

since insrutction can be 1,2 or 3 bytes we might need several clock cycles

• has address and data lines

• 64 kb

Why use unint_x variables Where should we use auto and how What are forward declarations ? and where are they used Circular Dependecy related to forward declarations