Arithmetic and Logic Calculator

Build an arithmetic and logic calculator that has:
1) Four input bits of data, stored in a single-bit register (D-type latch)
2) One carry-in bit, stored in a register (D-type latch)
3) Six instruction bits, each stored in a register (D-type latch).
a. The first and second bits of the instruction (B1 and B2) specify the
operation to be performed.
- 00 is a NOR operation
- 01 is a AND operation
- 10 is an NAND operation
- 11 is an ADD operation
b. The third and fourth bits of the instruction (B3 and B4) specify one
input data register which will be used in your calculation.
- Register 0 is addressed as 00
- Register 1 is addressed as 01
- Register 2 is addressed as 10
- Register 3 is addressed as 11.
c. The fifth and sixth bits of the instruction (B5 and B6) specify the
second input data register which will be used in your calculation.
- Register 0 is addressed as 00
- Register 1 is addressed as 01
- Register 2 is addressed as 10
- Register 3 is addressed as 11.
4) Each operator will perform a calculation on the input data from the registers
identified by bits B3, B4, B5 and B6.
5) ADD operations will also use the carry-in register.
6) If you perform a logical operation (NOR, AND or NAND), the output should
be stored in an output register (D-type latch).
7) If you perform an ADD, you should store the trailing bit in the output register,
and the leading bit in a carry-out register (D-type latch).


I have problems understand this problem i have to solve.
So i am to make a four single-bit register, but i don't know what i have to do for it.
I also have to make a six instruction bit, each stored in a register.
So how does B3 + B4 and B5 + B6 relate to the input bits ?
How am i supposed to make this curcuit

Thank you in advance.

Sounds like homework...

Yea i need help.

Why don't you use google and search for "ALU block diagram". Once you know the structure of an ALU it's pretty simple to implement in say VHDL or Verilog.