use std.textio.line;

package bv_arithmetic is
  
  -- Arithmetic on bit_vectors.
  
  -- Bit vectors are treated as either unsigned or signed (2's complement) numbers
  -- bv'first is the msb and bv'last is the lsb
  
  -- Dyadic operations assume the two bit vectors are the same length and index range.
  -- Functions assume the result is the same length and index range as arguments.

  function bv_to_natural (bv : in bit_vector) return natural;
  
  function natural_to_bv (nat : in natural;
      	      	      	  length : in natural) return bit_vector;

  function bv_to_integer (bv : in bit_vector) return integer;
  
  function integer_to_bv (int : in integer;
      	      	      	  length : in natural) return bit_vector;

  procedure bv_add (bv1, bv2 : in bit_vector;
      	       	    bv_result : out bit_vector;
		    overflow : out boolean);

  procedure bv_sub (bv1, bv2 : in bit_vector;
      	       	    bv_result : out bit_vector;
		    overflow : out boolean);

  procedure bv_addu (bv1, bv2 : in bit_vector;
      	       	     bv_result : out bit_vector;
		     overflow : out boolean);

  procedure bv_subu (bv1, bv2 : in bit_vector;
      	       	     bv_result : out bit_vector;
		     overflow : out boolean);

  function bv_sll (bv : in bit_vector;
       	      	   shift_count : in natural) return bit_vector;

  function bv_srl (bv : in bit_vector;
      	      	   shift_count : in natural) return bit_vector;

  function bv_sra (bv : in bit_vector;
      	      	   shift_count : in natural) return bit_vector;

  function bv_lt (bv1, bv2 : in bit_vector) return boolean;
  
  function bv_le (bv1, bv2 : in bit_vector) return boolean;
  
  function bv_gt (bv1, bv2 : in bit_vector) return boolean;
  
  function bv_ge (bv1, bv2 : in bit_vector) return boolean;
  
  function bv_sext (bv : in bit_vector;
      	      	    length : in natural) return bit_vector;
  
  function bv_zext (bv : in bit_vector;
      	      	    length : in natural) return bit_vector;
  
  procedure write_hex (L : inout line; b : in bit_vector);

end bv_arithmetic;