Subversion Repositories bluespec-h264

//**********************************************************************
// NAL unit unwrapper implementation
//----------------------------------------------------------------------
//
//

package mkNalUnwrap;

import H264Types::*;
import INalUnwrap::*;
import FIFO::*;

import Connectable::*;
import GetPut::*;



//-----------------------------------------------------------
// NAL Unwrapper Module
//-----------------------------------------------------------

module mkNalUnwrap( INalUnwrap );

   FIFO#(InputGenOT)  infifo    <- mkFIFO;
   FIFO#(NalUnwrapOT) outfifo   <- mkFIFO;
   Reg#(Bit#(8))      buffera   <- mkReg(0);
   Reg#(Bit#(8))      bufferb   <- mkReg(0);
   Reg#(Bit#(8))      bufferc   <- mkReg(0);
   Reg#(Bit#(2))      bufcount  <- mkReg(0);
   Reg#(Bit#(27))     zerocount <- mkReg(0);

   
   //-----------------------------------------------------------
   // Rules
   rule fillbuffer (bufcount<3
                    &&& infifo.first() matches tagged DataByte .dbyte);
      bufferc  <= bufferb;
      bufferb  <= buffera;
      buffera  <= dbyte;
      bufcount <= bufcount+1;
      infifo.deq();
   endrule

   rule newnalunit (bufcount==3
                    &&& infifo.first() matches tagged DataByte .dbyte
                    &&& ((bufferc==0 && bufferb==0 && buffera==1)
                         || (bufferc==0 && bufferb==0 && buffera==0 && dbyte==1)));
      zerocount <= 0;
      if(bufferc==0 && bufferb==0 && buffera==1)
         bufcount <= 0;
      else
         begin
            bufcount <= 0;
            infifo.deq();
         end
      outfifo.enq(NewUnit);
      $display("ccl1newunit");
   endrule

   rule remove3byte (bufcount==3
                     &&& infifo.first() matches tagged DataByte .dbyte
                     &&& (bufferc==0 && bufferb==0 && buffera==3 && dbyte<4));
      zerocount <= zerocount+2;
      bufcount  <= 0;
   endrule

   rule normalop (bufcount==3
                  &&& infifo.first() matches tagged DataByte .dbyte
                  &&& !(bufferc==0 && bufferb==0 && buffera==3 && dbyte<4)
                  &&& !((bufferc==0 && bufferb==0 && buffera==1)
                        || (bufferc==0 && bufferb==0 && buffera==0 && dbyte==1)));
      if(bufferc==0)
         begin
            zerocount <= zerocount+1;
            bufferc  <= bufferb;
            bufferb  <= buffera;
            buffera  <= dbyte;
            infifo.deq();
         end
      else if(zerocount==0)
         begin
            outfifo.enq(RbspByte bufferc);
            $display("ccl1rbspbyte %h", bufferc);
            bufferc  <= bufferb;
            bufferb  <= buffera;
            buffera  <= dbyte;
            infifo.deq();
         end
      else
         begin
            zerocount <= zerocount-1;
            outfifo.enq(RbspByte 0);
            $display("ccl1rbspbyte 00");
         end  
   endrule

   rule endfileop(infifo.first() matches tagged EndOfFile);
      case ( bufcount )
         3:
         begin
            if(bufferc==0 && bufferb==0 && buffera<4)
               begin
                  bufcount  <= 0;
                  zerocount <= 0;
               end
            else if(zerocount==0)
               begin
                  bufcount <= 2;
                  outfifo.enq(RbspByte bufferc);
                  $display("ccl1rbspbyte %h", bufferc);
               end
            else
               begin
                  zerocount <= zerocount-1;
                  outfifo.enq(RbspByte 0);
                  $display("ccl1rbspbyte 00");
               end
         end
         2:
         begin
            bufcount  <= 1;
            if(!(bufferb==0 && buffera==0))
               outfifo.enq(RbspByte bufferb);
               $display("ccl1rbspbyte %h", bufferb);
         end
         1:
         begin
            bufcount  <= 0;
            if(!(buffera==0))
               outfifo.enq(RbspByte buffera);
               $display("ccl1rbspbyte %h", buffera);
         end
         0:
         begin
            infifo.deq();
            outfifo.enq(EndOfFile);
            $display("EndOfFile reached (NalUnwrap)");
         end
      endcase
         
   endrule

   
   interface Put ioin  = fifoToPut(infifo);
   interface Get ioout = fifoToGet(outfifo);
      
endmodule

endpackage