//
// 8-bit sign-magnitude to 10-bit sign-magnitude 
// conversion block
//
// Niels Moseley - Moseley Instruments 2017
// http://www.moseleyinstruments.com
//
//
// C1: x*8
// C2: 301 + (x-38)*4 = 301 - 152 + x*4 = 149 + x*4
// C3: 425 + (x-69)*2 = 425 - 138 + x*2 = 287 + x*2
// C4: 481 + (x-97)   = 481 - 97  + x   = 384 + x
//
//
//
//

module XLAT (
        c8_in, 
        c10_out
    );

    input      [7:0] c8_in;
    output reg [9:0] c10_out;
    wire sign;

    assign sign = ~c8_in[7];

    always@(*)
    begin
        if (c8_in[6:0] < 38)
            c10_out <= {sign, c8_in[5:0], 3'b000};
        else if (c8_in[6:0] < 69)
            c10_out <= {sign, {c8_in[6:0], 2'b00} + 9'd149};
        else if (c8_in[6:0] < 97)
            c10_out <= {sign, {{1'b0, c8_in[6:0]}, 1'b0} + 9'd287};
        else
            c10_out <= {sign, {{2'b00, c8_in[6:0]} + 9'd384}};
    end
endmodule