Base64 Encoding in Verilog

Verilog does not have built-in support for base64 encoding/decoding, so we’ll implement a simplified version of base64 encoding and decoding using Verilog modules. This example will demonstrate the concept, but it won’t be a full-featured base64 implementation.

module base64_encoder(
    input wire [23:0] data_in,
    output reg [31:0] encoded_out
);
    reg [5:0] base64_chars [63:0];
    
    initial begin
        // Initialize base64 character set (simplified for this example)
        base64_chars[0] = "A"; base64_chars[1] = "B"; // ... and so on
    end
    
    always @(*) begin
        encoded_out[31:26] = base64_chars[data_in[23:18]];
        encoded_out[25:20] = base64_chars[data_in[17:12]];
        encoded_out[19:14] = base64_chars[data_in[11:6]];
        encoded_out[13:8] = base64_chars[data_in[5:0]];
        encoded_out[7:0] = "="; // Padding (simplified)
    end
endmodule

module base64_decoder(
    input wire [31:0] encoded_in,
    output reg [23:0] decoded_out
);
    reg [5:0] char_to_value [127:0];
    
    initial begin
        // Initialize reverse lookup table
        char_to_value["A"] = 0; char_to_value["B"] = 1; // ... and so on
    end
    
    always @(*) begin
        decoded_out[23:18] = char_to_value[encoded_in[31:26]];
        decoded_out[17:12] = char_to_value[encoded_in[25:20]];
        decoded_out[11:6] = char_to_value[encoded_in[19:14]];
        decoded_out[5:0] = char_to_value[encoded_in[13:8]];
    end
endmodule

module base64_example;
    reg [23:0] original_data;
    wire [31:0] encoded_data;
    wire [23:0] decoded_data;
    
    base64_encoder encoder(
        .data_in(original_data),
        .encoded_out(encoded_data)
    );
    
    base64_decoder decoder(
        .encoded_in(encoded_data),
        .decoded_out(decoded_data)
    );
    
    initial begin
        // Example usage
        original_data = 24'b010000110100000101010100; // "CAT"
        #10; // Wait for combinational logic to settle
        $display("Original: %b", original_data);
        $display("Encoded: %b", encoded_data);
        $display("Decoded: %b", decoded_data);
    end
endmodule

This Verilog code demonstrates a simplified base64 encoding and decoding process:

The base64_encoder module takes 24 bits of input data and produces a 32-bit encoded output.
The base64_decoder module takes a 32-bit encoded input and produces a 24-bit decoded output.
The base64_example module demonstrates how to use the encoder and decoder.

The encoding process converts groups of 6 bits into base64 characters, while the decoding process reverses this conversion. This example uses a simplified character set and doesn’t handle all edge cases of a full base64 implementation.

To run this Verilog code, you would typically use a Verilog simulator like Icarus Verilog or ModelSim. The simulation would output the original data, encoded data, and decoded data in binary format.

Note that this is a very basic implementation and doesn’t cover all aspects of base64 encoding/decoding. In practice, base64 encoding in hardware would often be implemented as part of a larger system, possibly using more optimized techniques or dedicated hardware blocks.

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Base64 Encoding in Verilog