URL https://opencores.org/ocsvn/video_systems/video_systems/trunk

Subversion Repositories video_systems

[/] [video_systems/] [trunk/] [common/] [entropy_coding/] [rtl/] [verilog/] [huffman_dec.v] - Blame information for rev 9

Go to most recent revision | Details | Compare with Previous | View Log


/////////////////////////////////////////////////////////////////////
////                                                             ////
////  JPEG Entropy Coding, Huffman Decoding                      ////
////                                                             ////
////  Decomposes incomming datastream into packets for the       ////
////  Huffman tables.                                            ////
////  See accompanying testbench how to use this code.           ////
////                                                             ////
////  Author: Richard Herveille                                  ////
////          richard@asics.ws                                   ////
////          www.asics.ws                                       ////
////                                                             ////
/////////////////////////////////////////////////////////////////////
////                                                             ////
//// Copyright (C) 2001 Richard Herveille                        ////
////                    richard@asics.ws                         ////
////                                                             ////
//// This source file may be used and distributed without        ////
//// restriction provided that this copyright statement is not   ////
//// removed from the file and that any derivative work contains ////
//// the original copyright notice and the associated disclaimer.////
////                                                             ////
////     THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY     ////
//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED   ////
//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS   ////
//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR      ////
//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,         ////
//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES    ////
//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE   ////
//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR        ////
//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF  ////
//// LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT  ////
//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT  ////
//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE         ////
//// POSSIBILITY OF SUCH DAMAGE.                                 ////
////                                                             ////
/////////////////////////////////////////////////////////////////////
 
//  CVS Log
//
//  $Id: huffman_dec.v,v 1.1 2002-10-29 20:07:53 rherveille Exp $
//
//  $Date: 2002-10-29 20:07:53 $
//  $Revision: 1.1 $
//  $Author: rherveille $
//  $Locker:  $
//  $State: Exp $
//
 
`include "timescale.v"
 
module huffman_dec(clk, rst, tablesel, di, die, do, doe, busy);
  input         clk;      // clock
  input         rst;      // asynchronous active low reset
  input  [ 1:0] tablesel; // huffman table select
  input  [ 7:0] di;       // data input
  input         die;      // data-in enable
  output [ 7:0] do;       // category or Runlenght/Size codepair
  output        doe;      // data-out enable
  output        busy;     // busy. Do not assert die while busy asserted
 
  reg [7:0] do;
  reg       doe, busy;
 
 
  wire [ 7:0] hdec_dc_lum, hdec_dc_chr;
  wire [11:0] hdec_ac_lum, hdec_ac_chr;
  reg  [ 4:0] codelen;
  reg  [15:0] code;
 
  reg [ 1:0] state;
  reg [22:0] sreg;
  reg [ 4:0] cnt;
 
 
  `include "huffman_tables.v"
 
  //
  // hookup huffman tables
  //
  assign hdec_dc_lum = jpeg_dc_luminance_huffman_dec(code[15:7]);
  assign hdec_dc_chr = jpeg_dc_chrominance_huffman_dec(code[15:5]);
  assign hdec_ac_lum = jpeg_ac_luminance_huffman_dec(code);
  assign hdec_ac_chr = jpeg_ac_chrominance_huffman_dec(code);
 
 
  //
  // split table data into category Run/Size and codelength
  //
  always @(posedge clk)
    case (tablesel) // synopsys full_case parallel_case
      2'b00: // DC Luminance
        begin
            codelen <= #1 hdec_dc_lum[ 7: 4] +4'h1;
            do      <= #1 {4'h0, hdec_dc_lum[ 3: 0]};
        end
 
      2'b01: // DC Chrominance
        begin
            codelen <= #1 hdec_dc_chr[ 7: 4] +4'h1;
            do      <= #1 {4'h0, hdec_dc_chr[ 3: 0]};
        end
 
      2'b10: // AC Luminance
        begin
            codelen <= #1 hdec_ac_lum[11:8] +4'h1;
            do      <= #1 hdec_ac_lum[ 7:0];
        end
 
      2'b11: // AC Chrominance
        begin
            codelen <= #1 hdec_ac_chr[11:8] +4'h1;
            do      <= #1 hdec_ac_chr[ 7:0];
        end
    endcase
 
 
  //
  // Hookup din statemachine
  //
  always @(posedge clk or negedge rst)
    if(~rst)
      begin
          state <= #1 2'b00;
          sreg  <= #1 24'h0;
          cnt   <= #1 5'h0;
          busy  <= #1 1'b0;
      end
    else
      begin
          doe <= #1 1'b0;
 
          case(state)
            2'b00:
                if(die)
                  begin
                      if( (cnt + 5'h8) > 15 ) // guaranteed valid code in sreg
                        begin
                            state <= #1 2'b01;
                            busy  <= #1 1'b1;
                        end
 
                        sreg <= #1 ((sreg << 8) | di);
                        cnt  <= #1 (cnt + 5'h8);
                  end
 
            2'b01:
                begin
                    state <= #1 2'b11; // wait for codelen (data from table)
                    doe   <= #1 1'b1;
                end
 
            2'b11:
                begin
                    if( (cnt - codelen) > 15 ) // still valid codes in sreg
                      state <= #1 2'b01;
                    else
                      begin
                          state <= #1 2'b00;
                          busy  <= #1 1'b0;
                      end
 
                    cnt  <= #1 (cnt - codelen);
                end
          endcase
      end
 
  always @(posedge clk)
    if(die)
      code <= #1 ((sreg << 8) | di) >> ((cnt + 5'h8) -5'h10);
    else
      code <= #1 sreg >> ((cnt - codelen) -5'h10);
 
endmodule

Line No.	Rev	Author	Line
1	9	rherveille	`/////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// JPEG Entropy Coding, Huffman Decoding ////`
4			`//// ////`
5			`//// Decomposes incomming datastream into packets for the ////`
6			`//// Huffman tables. ////`
7			`//// See accompanying testbench how to use this code. ////`
8			`//// ////`
9			`//// Author: Richard Herveille ////`
10			`//// richard@asics.ws ////`
11			`//// www.asics.ws ////`
12			`//// ////`
13			`/////////////////////////////////////////////////////////////////////`
14			`//// ////`
15			`//// Copyright (C) 2001 Richard Herveille ////`
16			`//// richard@asics.ws ////`
17			`//// ////`
18			`//// This source file may be used and distributed without ////`
19			`//// restriction provided that this copyright statement is not ////`
20			`//// removed from the file and that any derivative work contains ////`
21			`//// the original copyright notice and the associated disclaimer.////`
22			`//// ////`
23			//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
24			`//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////`
25			`//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////`
26			`//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////`
27			`//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////`
28			`//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////`
29			`//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////`
30			`//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////`
31			`//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////`
32			`//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////`
33			`//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////`
34			`//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////`
35			`//// POSSIBILITY OF SUCH DAMAGE. ////`
36			`//// ////`
37			`/////////////////////////////////////////////////////////////////////`
38
39			`// CVS Log`
40			`//`
41			`// $Id: huffman_dec.v,v 1.1 2002-10-29 20:07:53 rherveille Exp $`
42			`//`
43			`// $Date: 2002-10-29 20:07:53 $`
44			`// $Revision: 1.1 $`
45			`// $Author: rherveille $`
46			`// $Locker: $`
47			`// $State: Exp $`
48			`//`
49
50			`include "timescale.v"
51
52			`module huffman_dec(clk, rst, tablesel, di, die, do, doe, busy);`
53			`input clk; // clock`
54			`input rst; // asynchronous active low reset`
55			`input [ 1:0] tablesel; // huffman table select`
56			`input [ 7:0] di; // data input`
57			`input die; // data-in enable`
58			`output [ 7:0] do; // category or Runlenght/Size codepair`
59			`output doe; // data-out enable`
60			`output busy; // busy. Do not assert die while busy asserted`
61
62			`reg [7:0] do;`
63			`reg doe, busy;`
64
65
66			`wire [ 7:0] hdec_dc_lum, hdec_dc_chr;`
67			`wire [11:0] hdec_ac_lum, hdec_ac_chr;`
68			`reg [ 4:0] codelen;`
69			`reg [15:0] code;`
70
71			`reg [ 1:0] state;`
72			`reg [22:0] sreg;`
73			`reg [ 4:0] cnt;`
74
75
76			`include "huffman_tables.v"
77
78			`//`
79			`// hookup huffman tables`
80			`//`
81			`assign hdec_dc_lum = jpeg_dc_luminance_huffman_dec(code[15:7]);`
82			`assign hdec_dc_chr = jpeg_dc_chrominance_huffman_dec(code[15:5]);`
83			`assign hdec_ac_lum = jpeg_ac_luminance_huffman_dec(code);`
84			`assign hdec_ac_chr = jpeg_ac_chrominance_huffman_dec(code);`
85
86
87			`//`
88			`// split table data into category Run/Size and codelength`
89			`//`
90			`always @(posedge clk)`
91			`case (tablesel) // synopsys full_case parallel_case`
92			`2'b00: // DC Luminance`
93			`begin`
94			`codelen <= #1 hdec_dc_lum[ 7: 4] +4'h1;`
95			`do <= #1 {4'h0, hdec_dc_lum[ 3: 0]};`
96			`end`
97
98			`2'b01: // DC Chrominance`
99			`begin`
100			`codelen <= #1 hdec_dc_chr[ 7: 4] +4'h1;`
101			`do <= #1 {4'h0, hdec_dc_chr[ 3: 0]};`
102			`end`
103
104			`2'b10: // AC Luminance`
105			`begin`
106			`codelen <= #1 hdec_ac_lum[11:8] +4'h1;`
107			`do <= #1 hdec_ac_lum[ 7:0];`
108			`end`
109
110			`2'b11: // AC Chrominance`
111			`begin`
112			`codelen <= #1 hdec_ac_chr[11:8] +4'h1;`
113			`do <= #1 hdec_ac_chr[ 7:0];`
114			`end`
115			`endcase`
116
117
118			`//`
119			`// Hookup din statemachine`
120			`//`
121			`always @(posedge clk or negedge rst)`
122			`if(~rst)`
123			`begin`
124			`state <= #1 2'b00;`
125			`sreg <= #1 24'h0;`
126			`cnt <= #1 5'h0;`
127			`busy <= #1 1'b0;`
128			`end`
129			`else`
130			`begin`
131			`doe <= #1 1'b0;`
132
133			`case(state)`
134			`2'b00:`
135			`if(die)`
136			`begin`
137			`if( (cnt + 5'h8) > 15 ) // guaranteed valid code in sreg`
138			`begin`
139			`state <= #1 2'b01;`
140			`busy <= #1 1'b1;`
141			`end`
142
143			`sreg <= #1 ((sreg << 8) \| di);`
144			`cnt <= #1 (cnt + 5'h8);`
145			`end`
146
147			`2'b01:`
148			`begin`
149			`state <= #1 2'b11; // wait for codelen (data from table)`
150			`doe <= #1 1'b1;`
151			`end`
152
153			`2'b11:`
154			`begin`
155			`if( (cnt - codelen) > 15 ) // still valid codes in sreg`
156			`state <= #1 2'b01;`
157			`else`
158			`begin`
159			`state <= #1 2'b00;`
160			`busy <= #1 1'b0;`
161			`end`
162
163			`cnt <= #1 (cnt - codelen);`
164			`end`
165			`endcase`
166			`end`
167
168			`always @(posedge clk)`
169			`if(die)`
170			`code <= #1 ((sreg << 8) \| di) >> ((cnt + 5'h8) -5'h10);`
171			`else`
172			`code <= #1 sreg >> ((cnt - codelen) -5'h10);`
173
174			`endmodule`

Browse

Tools

Subversion Repositories video_systems

[/] [video_systems/] [trunk/] [common/] [entropy_coding/] [rtl/] [verilog/] [huffman_dec.v] - Blame information for rev 9