module ROM( output reg [7:0] rom_out, input [3:0] rom_in ); always @(*) begin rom_out = 8'bx; case(rom_in) 4'b0000: rom_out = 8'b0000_1001; //LDA 4'b0001: rom_out = 8'b0001_1010; //ADD 4'b0010: rom_out = 8'b0001_1011; //ADD 4'b0011: rom_out = 8'b0010_1100; //SUB 4'b0100: rom_out = 8'b1110_xxxx; //OUT 4'b0101: rom_out = 8'b1111_xxxx; //HLT 4'b0110: rom_out = 8'bxxxx_xxxx; 4'b0111: rom_out = 8'bxxxx_xxxx; 4'b1000: rom_out = 8'bxxxx_xxxx; 4'b1001: rom_out = 8'b0001_0000; 4'b1010: rom_out = 8'b0001_0100; 4'b1011: rom_out = 8'b0001_1000; 4'b1100: rom_out = 8'b0010_0000; endcase end endmodule