The definition of the operation code and the top module of ALU

When defining a control signal have no redundancy, the control signal is adequate at 4 bits.
The control signal of ALU can be simplified to take from machine code of the 13-10th bit of the KITE microprocessor.
Compare with instruction set table and let's attempt to confirm.

Operation Operation code
The addition (ADD) 0000
The subtraction (SUB) 0001
Inclement (INC) 0010
Decrement (DEC) 0011
Bitwise logical OR (OR) 0100
Bitwise logical exclusive OR (EOR) 0101
Bitwise logical AND (AND) 0110
Bitwise logical NOT (NOT) 0111
Logical left shift (LSL) 1000
Arithmetic left shift (ASL) 1001
Logical right shift (LSR) 1010
Arithmetic right shift (ASR) 1011
Anticlockwise-rotation (ROL) 1100
Clockwise-rotation (ROR) 1101
Pass through (PAS) 1110
Byte SWAP (SWP) 1111

The control code for ALU is described by "`define"by. By this definition, it is possible to refer a operation label instead of 0 and 1 bit pattern in the source code. 

'define IADD 4'b0000
'define ISUB 4'b0001
'define IINC 4'b0010
'define IDEC 4'b0011
'define IOR  4'b0100
'define IEOR 4'b0101
'define IAND 4'b0110
'define INOT 4'b0111
'define ILSL 4'b1000
'define IASL 4'b1001
'define ILSR 4'b1010
'define IASR 4'b1011
'define IROL 4'b1100
'define IROR 4'b1101
'define IPAS 4'b1110
'define ISWP 4'b1111
It is described beforehand to refer to the "alu_op.v" file from the "alu.v" file. 
`include "alu_op.v"

module alu (A, B, CB, Y, F) ;
  ...
  ...
  ...
  ...
  ...
endmodule

Next, description of calculation.

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