Subversion Repositories cavlc

//////////////////////////////////////////////////////////////////////
////                                                              ////
////  cavlc_len_gen                                               ////
////                                                              ////
////  Description                                                 ////
////      generate the number of bits to forward                  ////
////                                                              ////
////  Author(s):                                                  ////
////      - bin qiu, qiubin@opencores.org                         ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2011 Authors and OPENCORES.ORG                 ////
////                                                              ////
//// 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 source file is free software; you can redistribute it   ////
//// and/or modify it under the terms of the GNU Lesser General   ////
//// Public License as published by the Free Software Foundation; ////
//// either version 2.1 of the License, or (at your option) any   ////
//// later version.                                               ////
////                                                              ////
//// This source is distributed in the hope that it will be       ////
//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////
//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////
//// PURPOSE.  See the GNU Lesser General Public License for more ////
//// details.                                                     ////
////                                                              ////
//// You should have received a copy of the GNU Lesser General    ////
//// Public License along with this source; if not, download it   ////
//// from http://www.opencores.org/lgpl.shtml                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
 
//2011-8-7 20:19    initial revision
 
`include "defines.v"
 
module cavlc_len_gen
(
    cavlc_state,
    len_read_total_coeffs_comb,
    len_read_levels_comb,
    len_read_total_zeros_comb,
    len_read_run_befores_comb,
    len_comb
);
//------------------------
// ports
//------------------------
input  [7:0] cavlc_state;
input  [4:0] len_read_total_coeffs_comb;
input  [4:0] len_read_levels_comb;
input  [3:0] len_read_total_zeros_comb;
input  [3:0] len_read_run_befores_comb;
 
output [4:0] len_comb;
 
//------------------------
// regs
//------------------------
reg [4:0] len_comb;         //number of bits comsumed by cavlc in a cycle
 
//------------------------
// len_comb
//------------------------
always @ (*)
case (1'b1) //synthesis parallel_case
    cavlc_state[`cavlc_read_total_coeffs_bit]  : len_comb <= len_read_total_coeffs_comb;
    cavlc_state[`cavlc_read_t1s_flags_bit],  
    cavlc_state[`cavlc_read_level_prefix_bit],
    cavlc_state[`cavlc_read_level_suffix_bit]  : len_comb <= len_read_levels_comb;       
    cavlc_state[`cavlc_read_total_zeros_bit]   : len_comb <= len_read_total_zeros_comb;
    cavlc_state[`cavlc_read_run_befores_bit]   : len_comb <= len_read_run_befores_comb;
    cavlc_state[`cavlc_calc_level_bit],
    cavlc_state[`cavlc_idle_bit]               : len_comb <= 0;
    default                                    : len_comb <= 'bx;
endcase
 
endmodule