hello,

I have made sample code for 4 bit ALU and 3 to 8 decoder to make 4 bit processor . as designer we can design anything so I have started to design processor with two function ALU and decoder
4 bit alu

Module alu (a,b,s0,s1,s2 f);
Input a,b,s0,s1,s2;
Output f;
Reg [3:0];
Always @(s0,s1,s2);
Begian
Case (s0,s1,s2);
3b’000 :f=(a&b);
3b’001:f= (a|b);
3b’010 :f= ~(a&b);
3b’011 :f= ~ (a|b);
3b’100:f=(a^b);
3b’101: f=(a*b);
3b’110: f=(a+b);
3b’111:f=(a-b );
End case
End module

3to 8 decoder

Module decoder (a2,a1,a0, d7,d6,d5,d4,d3,d2,d1,d0);
Input a2,a1,a0;
Output d7,d6,d5,d4,d3,d2,d1,d0;
Wire [7:0];
Always @(a2,a1,a0);
Begin
Case (a2,a1,a0);
4’b000:( d7,d6,d5,d4,d3,d2,d1,d0)=00000001;
4’001: (d7,d6,d5,d4,d3,d2,d1,d0)=00000010;
4’b010: (d7,d6,d5,d4,d3,d2,d1,d0)=00000100;
4’b011: (d7,d6,d5,d4,d3,d2,d1,d0)=00001000;
4’b100:( d7,d6,d5,d4,d3,d2,d1,d0)=00010000;
4’b101:( d7,d6,d5,d4,d3,d2,d1,d0)=00100000;
4’b110: (d7,d6,d5,d4,d3,d2,d1,d0)=01000000;
4’b111: (d7,d6,d5,d4,d3,d2,d1,d0)=10000000;
Endcase
Endmodule

I don't understand how to connect 4 bit Alu with
3 to 8 bit decoder to make 4 bit processor

 

Well, I guess this is posted in the wrong forum.
Your question is about programming rather than electronics.

Another thing, you have a typo on your first 'code' "Begian"
And don't remember if it's "Endcase" or "End case", my verilog is rusted...