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//-------------------------------------------------------------------------------------------------- // Design : nova // Author(s) : Ke Xu // Email : eexuke@yahoo.com // File : level_decoding.v // Generated : June 9, 2005 // Copyright (C) 2008 Ke Xu //------------------------------------------------------------------------------------------------- // Description // Devive the level_prefix,level_suffix,suffixLength,levelSuffixSize,levelCode // In systemC,levelSuffixSize is decoded @LevelPrefix,in RTL,now changed to @LevelSuffix // level_suffix[7:0],levelCode[7:0],level[8:0] // 1. level_abs_tmp[8:0]:|levelCode+2| or |-levelCode-1| | reg // 2. level_abs [7:0]:level_abs_tmp >> 1 and latched, used for suffixLength calculation | wire // 3. level_tmp [8:0]:2's complement, equals (levelCode+2)>>1 or (-levelCode-1)>>1 | wire // 4. level_0 ~ level_15:According to i_level,level_tmp is assigned to level_[i_level] | reg // level_0 ~ level_15 are 2's complement //------------------------------------------------------------------------------------------------- // synopsys translate_off `include "timescale.v" // synopsys translate_on `include "nova_defines.v" module level_decoding (clk,reset_n,cavlc_decoder_state,heading_one_pos,suffix_length_initialized,i_level, TotalCoeff,TrailingOnes,BitStream_buffer_output, levelSuffixSize, level_0,level_1,level_2, level_3, level_4, level_5, level_6, level_7, level_8,level_9,level_10,level_11,level_12,level_13,level_14,level_15); input clk,reset_n; input [3:0] cavlc_decoder_state; input [3:0] heading_one_pos; input suffix_length_initialized; input [3:0] i_level; input [4:0] TotalCoeff; input [1:0] TrailingOnes; input [15:0] BitStream_buffer_output; output [3:0] levelSuffixSize; output [8:0] level_0,level_1,level_2,level_3,level_4,level_5,level_6,level_7; output [8:0] level_8,level_9,level_10,level_11,level_12,level_13,level_14,level_15; reg [3:0] levelSuffixSize; reg [8:0] level_0,level_1,level_2,level_3,level_4,level_5,level_6,level_7; reg [8:0] level_8,level_9,level_10,level_11,level_12,level_13,level_14,level_15; reg [3:0] level_prefix; reg [3:0] suffixLength; reg [11:0] level_suffix; reg [8:0] levelCode; reg [8:0] level_tmp; reg [7:0] level_abs; wire [8:0] levelCode_tmp; //@LevelPrefix,latch the result always @ (posedge clk) if (reset_n == 0) level_prefix <= 0; else if (cavlc_decoder_state == `LevelPrefix) level_prefix <= heading_one_pos; //@LevelPrefix,latch the result always @ (posedge clk) if (reset_n == 0) suffixLength <= 0; else if (cavlc_decoder_state == `LevelPrefix) begin if (suffix_length_initialized == 1'b0) suffixLength <= (TotalCoeff > 10 && TrailingOnes < 3)? 4'd1:4'd0; //Revise log:March 26,2006 //else if (suffixLength == 0 && ((level_abs > (8'd3 << (suffixLength - 1))) && suffixLength < 6)) else if (suffixLength == 0 && level_abs > 8'd3) suffixLength <= 4'd2; else if (suffixLength == 0) suffixLength <= 4'd1; else if ((level_abs > (8'd3 << (suffixLength - 1))) && suffixLength < 6) suffixLength <= suffixLength + 1; end //@LevelSuffix,temporary result always @ (cavlc_decoder_state or level_prefix or suffixLength) if (cavlc_decoder_state == `LevelSuffix) begin if (level_prefix == 14 && suffixLength == 0) levelSuffixSize <= 4; else if (level_prefix == 4'd15) levelSuffixSize <= 4'd12; else levelSuffixSize <= suffixLength; end else levelSuffixSize <= 0; //@LevelSuffix,temporay result always @ (cavlc_decoder_state or levelSuffixSize or BitStream_buffer_output) if (cavlc_decoder_state == `LevelSuffix) begin if (levelSuffixSize == 0) level_suffix <= 0; else case (levelSuffixSize) 1 :level_suffix <= {11'b0,BitStream_buffer_output[15]}; 2 :level_suffix <= {10'b0,BitStream_buffer_output[15:14]}; 3 :level_suffix <= {9'b0,BitStream_buffer_output[15:13]}; 4 :level_suffix <= {8'b0,BitStream_buffer_output[15:12]}; 5 :level_suffix <= {7'b0,BitStream_buffer_output[15:11]}; 6 :level_suffix <= {6'b0,BitStream_buffer_output[15:10]}; 7 :level_suffix <= {5'b0,BitStream_buffer_output[15:9]}; 8 :level_suffix <= {4'b0,BitStream_buffer_output[15:8]}; 9 :level_suffix <= {3'b0,BitStream_buffer_output[15:7]}; 10:level_suffix <= {2'b0,BitStream_buffer_output[15:6]}; 11:level_suffix <= {1'b0,BitStream_buffer_output[15:5]}; 12:level_suffix <= BitStream_buffer_output[15:4]; default:level_suffix <= 0; endcase end else level_suffix <= 0; assign levelCode_tmp = (cavlc_decoder_state == `LevelSuffix)? ((level_prefix << suffixLength) + level_suffix):0; always @ (cavlc_decoder_state or level_prefix or suffixLength or i_level or TrailingOnes or levelCode_tmp) if (cavlc_decoder_state == `LevelSuffix) begin if (level_prefix == 15 && suffixLength == 0 && i_level == {2'b0,TrailingOnes} && TrailingOnes < 3) levelCode <= levelCode_tmp + 17; else if (level_prefix == 15 && suffixLength == 0) levelCode <= levelCode_tmp + 15; else if (i_level == {2'b0,TrailingOnes} && TrailingOnes < 3) levelCode <= levelCode_tmp + 2; else levelCode <= levelCode_tmp; end else levelCode <= 0; //We need an additional "level_abs" signal here in order to upgrade suffixLength for next codeword,but for //trailingones,no need to do so since abs(+1/-1) will never greater than (3<<(suffixLength-1)). //level_abs_tmp:absolute value of level reg [8:0] level_abs_tmp; always @ (cavlc_decoder_state or levelCode) if (cavlc_decoder_state == `LevelSuffix) begin if (levelCode[0] == 1'b0) //even level_abs_tmp <= levelCode + 2; else level_abs_tmp <= levelCode + 1; end else level_abs_tmp <= 0; //level_abs:latched absolute value of level,for upgrading of suffixLength always @ (posedge clk) if (reset_n == 0) level_abs <= 0; else if (cavlc_decoder_state == `LevelSuffix) level_abs <= level_abs_tmp[8:1]; always @ (cavlc_decoder_state or levelCode or level_abs_tmp) if (cavlc_decoder_state == `LevelSuffix) begin if (levelCode[0] == 1'b0) //even level_tmp <= {1'b0,level_abs_tmp[8:1]}; else level_tmp <= {1'b1,~levelCode[8:1]}; end else level_tmp <= 0; always @ (posedge clk) if (reset_n == 0) begin level_0 <= 0; level_1 <= 0; level_2 <= 0; level_3 <= 0; level_4 <= 0; level_5 <= 0; level_6 <= 0; level_7 <= 0; level_8 <= 0; level_9 <= 0; level_10<= 0; level_11<= 0; level_12<= 0; level_13<= 0; level_14<= 0; level_15<= 0; end else if (cavlc_decoder_state == `TrailingOnesSignFlag) begin level_0 <= (BitStream_buffer_output[15] == 0)? 9'b000000001:9'b111111111; if (TrailingOnes > 1) level_1 <= (BitStream_buffer_output[14] == 0)? 9'b000000001:9'b111111111; if (TrailingOnes == 3) level_2 <= (BitStream_buffer_output[13] == 0)? 9'b000000001:9'b111111111; end else if (cavlc_decoder_state == `LevelSuffix) case (i_level) 0 :level_0 <= level_tmp; 1 :level_1 <= level_tmp; 2 :level_2 <= level_tmp; 3 :level_3 <= level_tmp; 4 :level_4 <= level_tmp; 5 :level_5 <= level_tmp; 6 :level_6 <= level_tmp; 7 :level_7 <= level_tmp; 8 :level_8 <= level_tmp; 9 :level_9 <= level_tmp; 10:level_10<= level_tmp; 11:level_11<= level_tmp; 12:level_12<= level_tmp; 13:level_13<= level_tmp; 14:level_14<= level_tmp; 15:level_15<= level_tmp; endcase endmodule