--------------------------------------------------------------------------
--------------------------------------------------------------------------
--      File Name       : pred_fns.v
--      Author(s)       : Jay(anta) Roy
--      Affiliation     : Laboratory for Digital Design Environments
--                        Department of Electrical & Computer Engineering
--                        University of Cincinnati
--      Date Created    : June 1991.
--      Introduction    : Functions/Procedures needed for simulating the
--			  Benchmarks. These are functions that are either
--			  ignored by the synthesis system, or hold special
--			  meaning for the synthesis system.
--
--      Disclaimer      : This comes with absolutely no guarantees of any
--                        kind (just stating the obvious ...)
--
--      Acknowledgement : The Distributed Synthesis Systems research at
--                        the Laboratory for Digital Design Environments,
--                        University of Cincinnati, is sponsored in part
--                        by the Defense Advanced Research Projects Agency
--                        under order number 7056 monitored by the Federal
--                        Bureau of Investigation under contract number
--                        J-FBI-89-094.
--
--------------------------------------------------------------------------
--------------------------------------------------------------------------

package functions is
  type int_arr is array(Integer range<>) of INTEGER;
  type bit_arr is array(Integer range<>) of Bit;
  function int_Wired_OR (input : int_arr) return INTEGER;
  function bit_Wired_OR (input : bit_arr) return Bit;
  function bit_Wired_AND (input : bit_arr) return Bit;
  function bits_to_int (input : Bit_Vector) return INTEGER ;
  function "+" (Left, Right : Bit_Vector) return Bit_Vector;
  function "+" (Left : Bit_Vector; Right : Integer) return Bit_Vector;
  function "+" (Left : Integer; Right : Bit_Vector) return Bit_Vector;
  function "-" (Left, Right : Bit_Vector) return Bit_Vector;
  function "-" (Left : Bit_Vector; Right : Integer) return Bit_Vector;
  function "-" (Left : Integer; Right : Bit_Vector) return Bit_Vector;
  function "/" (Left, Right : Bit_Vector) return Bit_Vector;
  function "/" (Left : Bit_Vector; Right : Integer) return Bit_Vector;
  function "/" (Left : Integer; Right : Bit_Vector) return Integer;
  function "*" (Left, Right : Bit_Vector) return Bit_Vector;
  function "*" (Left : Bit_Vector; Right : Integer) return Bit_Vector;
  function "*" (Left : Integer; Right : Bit_Vector) return Integer;
  procedure left_shift (InpReg : inout Bit_Vector);
  procedure sig_left_shift (signal InpReg : inout Bit_Vector);
  procedure right_shift (InpReg : inout Bit_Vector);
  procedure sig_right_shift (signal InpReg : inout Bit_Vector);
end functions;

package body functions is
  procedure left_shift(InpReg : inout Bit_Vector) is
  begin
    if (InpReg'LEFT >= InpReg'Right)
    then
       for i in InpReg'RANGE loop
         if i > InpReg'LOW
         then
           InpReg(i) := InpReg(i-1);
         end if;
       end loop;
       InpReg(InpReg'LOW) := '0';
    else
       for i in InpReg'RANGE loop
	 if i < InpReg'HIGH
	 then
	   InpReg(i) := InpReg(i+1);
	 end if;
       end loop;
       InpReg(InpReg'HIGH) := '0';
    end if; 
  end left_shift;

  procedure sig_left_shift(signal InpReg : inout Bit_Vector) is
  begin
    if (InpReg'LEFT >= InpReg'Right)
    then
       for i in InpReg'RANGE loop
         if i > InpReg'LOW
         then
           InpReg(i) <= InpReg(i-1);
         end if;
       end loop;
       InpReg(InpReg'LOW) <= '0';
    else
       for i in InpReg'RANGE loop
         if i < InpReg'HIGH         
         then
           InpReg(i) <= InpReg(i+1);
         end if;
       end loop;
       InpReg(InpReg'HIGH) <= '0';
    end if;
  end sig_left_shift;

  procedure right_shift(InpReg : inout Bit_Vector) is
  begin
    if (InpReg'Left >= InpReg'Right)
    then
       for i in InpReg'REVERSE_RANGE loop
         if i < InpReg'HIGH
         then
           InpReg(i) := InpReg(i+1);
         end if;
       end loop;
       InpReg(InpReg'HIGH) := '0';
    else
       for i in InpReg'RANGE loop
         if i > InpReg'LOW
         then
	    InpReg(i) := InpReg(i-1);
         end if;
       end loop;
       InpReg(InpReg'LOW) := '0';
     end if;
  end right_shift;

  procedure sig_right_shift(signal InpReg : inout Bit_Vector) is
  begin
    if (InpReg'Left >= InpReg'Right)
    then
       for i in InpReg'REVERSE_RANGE loop
         if i < InpReg'HIGH
         then
           InpReg(i) <= InpReg(i+1);
         end if;
       end loop;
       InpReg(InpReg'HIGH) <= '0';
    else
       for i in InpReg'RANGE loop
         if i > InpReg'LOW
         then
            InpReg(i) <= InpReg(i-1);
         end if;
       end loop;
       InpReg(InpReg'LOW) <= '0';
    end if;
  end sig_right_shift;

  function int_Wired_OR(input : int_arr) return INTEGER is
  variable resolved_value : INTEGER := 0;
  begin
    for i in input'RANGE loop
      if input(i) > 0 then
	resolved_value := input(i);
      end if;
    end loop;
    return resolved_value;
   end int_Wired_OR;

  function bits_to_int (input : Bit_Vector )return INTEGER is
   variable ret_val : INTEGER := 0;
  begin
    for i in input'RANGE loop
      if input(i) = '1' then
	ret_val := 2**i + ret_val;
      end if;
    end loop;
    return ret_val;
  end bits_to_int;

  function bit_Wired_OR (input : bit_arr) return Bit is
  variable resolved_value : Bit;
  begin
    for i in input'RANGE loop
      if input(i) = '1' then return '1';
      end if;
    end loop;
    return '0';
  end bit_Wired_OR;

  function bit_Wired_AND (input : bit_arr) return Bit is
  variable resolved_value : Bit;
  begin
    for i in input'RANGE loop
      if input(i) = '0' then return '0';
      end if;
    end loop;
    return '1';
  end bit_Wired_AND;

  function "+" (Left, Right : Bit_Vector) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Length downto 0);
  variable carry : Bit := '0';
  variable dummy : Bit_Vector(0 to 2);
  variable i : Integer;
  begin
     for i in Left'Reverse_Range loop
	dummy(0) := Left(i);
	dummy(1) := Right(i);
	dummy(2) := carry;
        case dummy is
	  when "000" => 
	    return_vector(i) := '0';
	    carry := '0';
	  when "001" => 
	    return_vector(i) := '1';
	    carry := '0';
	  when "010" => 
	    return_vector(i) := '1';
	    carry := '0';
	  when "011" => 
	    return_vector(i) := '0';
	    carry := '1';
	  when "100" => 
	    return_vector(i) := '1';
	    carry := '0';
	  when "101" => 
	    return_vector(i) := '0';
	    carry := '1';
	  when "110" => 
	    return_vector(i) := '0';
	    carry := '1';
	  when "111" => 
	    return_vector(i) := '1';
	    carry := '1';
	end case;
     end loop;
     return_vector(Left'Length) := carry;
     return return_vector;
  end;

  function "+" (Left : Bit_Vector; Right : Integer) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Range);
  variable Right_rem, Right_val : Integer;
  variable carry : Bit := '0';
  begin
     Right_val := Right;
     for i in Left'Range loop
	Right_rem := Right_val rem 2;
	Right_val := Right_val / 2;
	if Right_rem = 1 then
	   return_vector(i) := '1';
	else
	   return_vector(i) := '0';
	end if;
     end loop;
     return_vector := return_vector + Left;
     return return_vector;
  end;

  function "+" (Left : Integer; Right : Bit_Vector) return Bit_Vector is
  variable return_vector : Bit_Vector(Right'Range);
  variable Left_rem, Left_val : Integer;
  variable carry : Bit := '0';
  begin
     Left_val := Left;
     for i in Right'Range loop
	Left_rem := Left_val rem 2;
	Left_val := Left_val / 2;
	if Left_rem = 1 then
	   return_vector(i) := '1';
	else
	   return_vector(i) := '0';
	end if;
     end loop;
     return_vector := return_vector + Left;
     return return_vector;
  end;

  function "-" (Left, Right : Bit_Vector) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Length downto 0);
  variable borrow : Bit := '0';
  variable dummy : Bit_Vector(2 downto 0);
  variable i : Integer;
  begin
     for i in Left'Reverse_Range loop
	dummy(2) := Left(i);
	dummy(1) := Right(i);
	dummy(0) := borrow;
        case dummy is
	  when "000" => 
	    return_vector(i) := '0';
	    borrow := '0';
	  when "001" => 
	    return_vector(i) := '1';
	    borrow := '1';
	  when "010" => 
	    return_vector(i) := '1';
	    borrow := '1';
	  when "011" => 
	    return_vector(i) := '0';
	    borrow := '1';
	  when "100" => 
	    return_vector(i) := '1';
	    borrow := '0';
	  when "101" => 
	    return_vector(i) := '0';
	    borrow := '0';
	  when "110" => 
	    return_vector(i) := '0';
	    borrow := '0';
	  when "111" => 
	    return_vector(i) := '1';
	    borrow := '1';
	end case;
     end loop;
     return_vector(Left'Length) := borrow;
     return return_vector;
  end;

  function "-" (Left : Bit_Vector; Right : Integer) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Range);
  variable Right_rem, Right_val : Integer;
  variable carry : Bit := '0';
  begin
     Right_val := Right;
     for i in Left'Range loop
	Right_rem := Right_val rem 2;
	Right_val := Right_val / 2;
	if Right_rem = 1 then
	   return_vector(i) := '1';
	else
	   return_vector(i) := '0';
	end if;
     end loop;
     return_vector := Left - return_vector;
     return return_vector;
  end;

  function "-" (Left : Integer; Right : Bit_Vector) return Bit_Vector is
  variable return_vector : Bit_Vector(Right'Range);
  variable Left_rem, Left_val : Integer;
  variable carry : Bit := '0';
  begin
     Left_val := Left;
     for i in Right'Range loop
	Left_rem := Left_val rem 2;
	Left_val := Left_val / 2;
	if Left_rem = 1 then
	   return_vector(i) := '1';
	else
	   return_vector(i) := '0';
	end if;
     end loop;
     return_vector := Left - return_vector;
     return return_vector;
  end;

  function "/" (Left,Right : Bit_Vector) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Range);
  variable Right_val : Integer;
  variable Left_rem,Left_val : Integer;
  begin
     Left_val := bits_to_int(Left);
     Right_val := bits_to_int(Right);
     Left_val := Left_val / Right_val;
     for i in Left'Range loop
        Left_rem := Left_val rem 2;
        Left_val := Left_val / 2;
        if Left_rem = 1 then
           return_vector(i) := '1';
        else
           return_vector(i) := '0';
        end if;
     end loop;
     return return_vector;
  end;

  function "/" (Left : Bit_Vector; Right : Integer) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Range);
  variable Left_rem,Left_val : Integer;
  begin
     Left_val := bits_to_int(Left);
     Left_val := Left_val / Right;
     for i in Left'Range loop
        Left_rem := Left_val rem 2;
        Left_val := Left_val / 2;
        if Left_rem = 1 then
           return_vector(i) := '1';
        else
           return_vector(i) := '0';
        end if;
     end loop;
     return return_vector;
  end;

  function "/" (Left : Integer; Right : Bit_Vector) return Integer is
  variable return_val : Integer;
  begin
     return_val := bits_to_int(Right);
     return_val := Left / return_val;
     return return_val;
  end;

  function "*" (Left,Right : Bit_Vector) return Bit_Vector is
  variable return_vector : Bit_Vector(0 to (Left'Length + Right'Length -1));
  variable Right_val : Integer;
  variable Left_rem,Left_val : Integer;
  begin
     Left_val := bits_to_int(Left);
     Right_val := bits_to_int(Right);
     Left_val := Left_val * Right_val;
     for i in return_vector'Range loop
        Left_rem := Left_val rem 2;
        Left_val := Left_val / 2;
        if Left_rem = 1 then
           return_vector(i) := '1';
        else
           return_vector(i) := '0';
        end if;
     end loop;
     return return_vector;
  end;

  function "*" (Left : Bit_Vector; Right : Integer) return Bit_Vector is
  variable return_vector : Bit_Vector(Left'Range);
  variable Left_rem,Left_val : Integer;
  begin
     Left_val := bits_to_int(Left);
     Left_val := Left_val * Right;
     for i in Left'Range loop
        Left_rem := Left_val rem 2;
        Left_val := Left_val / 2;
        if Left_rem = 1 then
           return_vector(i) := '1';
        else
           return_vector(i) := '0';
        end if;
     end loop;
     return return_vector;
  end;

  function "*" (Left : Integer; Right : Bit_Vector) return Integer is
  variable return_val : Integer;
  begin
     return_val := bits_to_int(Right);
     return_val := Left * return_val;
     return return_val;
  end;

end functions;