huffman_tables.v

基于FPGA的JPEG图像压缩芯片设计

/*
  J P E G _ A C _ L U M I N A N C E _ H U F F M A N _ D E C

  ITU-T.81 annex K.3.2 Table K.5

  This function translates the default Huffman codeword into
  luminance AC (RunLength, Size) codepair.

  Output is given as:
  codelength[3:0]-1, RunLength[3:0], size[3:0]

  The codewords are left-alligned to ease bitstream decomposition.

  example:
  codeword   = 16'b0000_0001_1111_0111
  codelength = 8 +1 = 9
  ac_luminance_run_length      = 3
  ac_limunance_size (category) = 2
*/
function [11:0] jpeg_ac_luminance_huffman_dec;
  input [15:0] codeword;
begin
  casex(codeword) // synopsys full_case parallel_case
    16'b1010_????_????_????: jpeg_ac_luminance_huffman_dec = {4'h3, 8'h00}; // EOB
    16'b00??_????_????_????: jpeg_ac_luminance_huffman_dec = {4'h1, 8'h01};
    16'b01??_????_????_????: jpeg_ac_luminance_huffman_dec = {4'h1, 8'h02};
    16'b100?_????_????_????: jpeg_ac_luminance_huffman_dec = {4'h2, 8'h03};
    16'b1011_????_????_????: jpeg_ac_luminance_huffman_dec = {4'h3, 8'h04};
    16'b1101_0???_????_????: jpeg_ac_luminance_huffman_dec = {4'h4, 8'h05};
    16'b1111_000?_????_????: jpeg_ac_luminance_huffman_dec = {4'h6, 8'h06};
    16'b1111_1000_????_????: jpeg_ac_luminance_huffman_dec = {4'h7, 8'h07};
    16'b1111_1101_10??_????: jpeg_ac_luminance_huffman_dec = {4'h9, 8'h08};
    16'b1111_1111_1000_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h09};
    16'b1111_1111_1000_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h0a};

    16'b1100_????_????_????: jpeg_ac_luminance_huffman_dec = {4'h3, 8'h11};
    16'b1101_1???_????_????: jpeg_ac_luminance_huffman_dec = {4'h4, 8'h12};
    16'b1111_001?_????_????: jpeg_ac_luminance_huffman_dec = {4'h6, 8'h13};
    16'b1111_1011_0???_????: jpeg_ac_luminance_huffman_dec = {4'h8, 8'h14};
    16'b1111_1110_110?_????: jpeg_ac_luminance_huffman_dec = {4'ha, 8'h15};
    16'b1111_1111_1000_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h16};
    16'b1111_1111_1000_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h17};
    16'b1111_1111_1000_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h18};
    16'b1111_1111_1000_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h19};
    16'b1111_1111_1000_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h1a};

    16'b1110_0???_????_????: jpeg_ac_luminance_huffman_dec = {4'h4, 8'h21};
    16'b1111_1001_????_????: jpeg_ac_luminance_huffman_dec = {4'h7, 8'h22};
    16'b1111_1101_11??_????: jpeg_ac_luminance_huffman_dec = {4'h9, 8'h23};
    16'b1111_1111_0100_????: jpeg_ac_luminance_huffman_dec = {4'hb, 8'h24};
    16'b1111_1111_1000_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h25};
    16'b1111_1111_1000_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h26};
    16'b1111_1111_1000_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h27};
    16'b1111_1111_1000_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h28};
    16'b1111_1111_1000_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h29};
    16'b1111_1111_1000_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h2a};

    16'b1110_10??_????_????: jpeg_ac_luminance_huffman_dec = {4'h5, 8'h31};
    16'b1111_1011_1???_????: jpeg_ac_luminance_huffman_dec = {4'h8, 8'h32};
    16'b1111_1111_0101_????: jpeg_ac_luminance_huffman_dec = {4'hb, 8'h33};
    16'b1111_1111_1000_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h34};
    16'b1111_1111_1001_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h35};
    16'b1111_1111_1001_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h36};
    16'b1111_1111_1001_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h37};
    16'b1111_1111_1001_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h38};
    16'b1111_1111_1001_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h39};
    16'b1111_1111_1001_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h3a};

    16'b1110_11??_????_????: jpeg_ac_luminance_huffman_dec = {4'h5, 8'h41};
    16'b1111_1110_00??_????: jpeg_ac_luminance_huffman_dec = {4'h9, 8'h42};
    16'b1111_1111_1001_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h43};
    16'b1111_1111_1001_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h44};
    16'b1111_1111_1001_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h45};
    16'b1111_1111_1001_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h46};
    16'b1111_1111_1001_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h47};
    16'b1111_1111_1001_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h48};
    16'b1111_1111_1001_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h49};
    16'b1111_1111_1001_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h4a};

    16'b1111_010?_????_????: jpeg_ac_luminance_huffman_dec = {4'h6, 8'h51};
    16'b1111_1110_111?_????: jpeg_ac_luminance_huffman_dec = {4'ha, 8'h52};
    16'b1111_1111_1001_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h53};
    16'b1111_1111_1001_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h54};
    16'b1111_1111_1010_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h55};
    16'b1111_1111_1010_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h56};
    16'b1111_1111_1010_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h57};
    16'b1111_1111_1010_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h58};
    16'b1111_1111_1010_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h59};
    16'b1111_1111_1010_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h5a};

    16'b1111_011?_????_????: jpeg_ac_luminance_huffman_dec = {4'h6, 8'h61};
    16'b1111_1111_0110_????: jpeg_ac_luminance_huffman_dec = {4'hb, 8'h62};
    16'b1111_1111_1010_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h63};
    16'b1111_1111_1010_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h64};
    16'b1111_1111_1010_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h65};
    16'b1111_1111_1010_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h66};
    16'b1111_1111_1010_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h67};
    16'b1111_1111_1010_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h68};
    16'b1111_1111_1010_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h69};
    16'b1111_1111_1010_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h6a};

    16'b1111_1010_????_????: jpeg_ac_luminance_huffman_dec = {4'h7, 8'h71};
    16'b1111_1111_0111_????: jpeg_ac_luminance_huffman_dec = {4'hb, 8'h72};
    16'b1111_1111_1010_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h73};
    16'b1111_1111_1010_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h74};
    16'b1111_1111_1011_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h75};
    16'b1111_1111_1011_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h76};
    16'b1111_1111_1011_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h77};
    16'b1111_1111_1011_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h78};
    16'b1111_1111_1011_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h79};
    16'b1111_1111_1011_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h7a};

    16'b1111_1100_0???_????: jpeg_ac_luminance_huffman_dec = {4'h8, 8'h81};
    16'b1111_1111_1000_000?: jpeg_ac_luminance_huffman_dec = {4'he, 8'h82};
    16'b1111_1111_1011_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h83};
    16'b1111_1111_1011_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h84};
    16'b1111_1111_1011_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h85};
    16'b1111_1111_1011_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h86};
    16'b1111_1111_1011_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h87};
    16'b1111_1111_1011_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h88};
    16'b1111_1111_1011_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h89};
    16'b1111_1111_1011_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h8a};

    16'b1111_1100_1???_????: jpeg_ac_luminance_huffman_dec = {4'h8, 8'h91};
    16'b1111_1111_1011_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h92};
    16'b1111_1111_1011_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h93};
    16'b1111_1111_1100_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h94};
    16'b1111_1111_1100_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h95};
    16'b1111_1111_1100_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h96};
    16'b1111_1111_1100_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h97};
    16'b1111_1111_1100_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h98};
    16'b1111_1111_1100_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h99};
    16'b1111_1111_1100_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'h9a};

    16'b1111_1101_0???_????: jpeg_ac_luminance_huffman_dec = {4'h8, 8'ha1};
    16'b1111_1111_1100_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha2};
    16'b1111_1111_1100_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha3};
    16'b1111_1111_1100_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha4};
    16'b1111_1111_1100_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha5};
    16'b1111_1111_1100_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha6};
    16'b1111_1111_1100_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha7};
    16'b1111_1111_1100_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha8};
    16'b1111_1111_1100_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'ha9};
    16'b1111_1111_1100_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'haa};

    16'b1111_1110_01??_????: jpeg_ac_luminance_huffman_dec = {4'h9, 8'hb1};
    16'b1111_1111_1101_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb2};
    16'b1111_1111_1101_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb3};
    16'b1111_1111_1101_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb4};
    16'b1111_1111_1101_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb5};
    16'b1111_1111_1101_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb6};
    16'b1111_1111_1101_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb7};
    16'b1111_1111_1101_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb8};
    16'b1111_1111_1101_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hb9};
    16'b1111_1111_1101_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hba};

    16'b1111_1110_10??_????: jpeg_ac_luminance_huffman_dec = {4'h9, 8'hc1};
    16'b1111_1111_1101_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc2};
    16'b1111_1111_1101_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc3};
    16'b1111_1111_1101_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc4};
    16'b1111_1111_1101_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc5};
    16'b1111_1111_1101_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc6};
    16'b1111_1111_1101_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc7};
    16'b1111_1111_1101_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc8};
    16'b1111_1111_1110_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hc9};
    16'b1111_1111_1110_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hca};

    16'b1111_1111_000?_????: jpeg_ac_luminance_huffman_dec = {4'ha, 8'hd1};
    16'b1111_1111_1110_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd2};
    16'b1111_1111_1110_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd3};
    16'b1111_1111_1110_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd4};
    16'b1111_1111_1110_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd5};
    16'b1111_1111_1110_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd6};
    16'b1111_1111_1110_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd7};
    16'b1111_1111_1110_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd8};
    16'b1111_1111_1110_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hd9};
    16'b1111_1111_1110_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hda};

    16'b1111_1111_1110_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he1};
    16'b1111_1111_1110_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he2};
    16'b1111_1111_1110_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he3};
    16'b1111_1111_1110_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he4};
    16'b1111_1111_1110_1111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he5};
    16'b1111_1111_1111_0000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he6};
    16'b1111_1111_1111_0001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he7};
    16'b1111_1111_1111_0010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he8};
    16'b1111_1111_1111_0011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'he9};
    16'b1111_1111_1111_0100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hea};

    16'b1111_1111_001?_????: jpeg_ac_luminance_huffman_dec = {4'ha, 8'hf0}; // ZRL
    16'b1111_1111_1111_0101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf1};
    16'b1111_1111_1111_0110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf2};
    16'b1111_1111_1111_0111: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf3};
    16'b1111_1111_1111_1000: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf4};
    16'b1111_1111_1111_1001: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf5};
    16'b1111_1111_1111_1010: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf6};
    16'b1111_1111_1111_1011: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf7};
    16'b1111_1111_1111_1100: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf8};
    16'b1111_1111_1111_1101: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hf9};
    16'b1111_1111_1111_1110: jpeg_ac_luminance_huffman_dec = {4'hf, 8'hfa};

  endcase
end
endfunction // jpeg_ac_luminance_huffman_dec