#integer related kernel functions
module Register
  module Builtin
    module Integer
      module ClassMethods
        def plus c
          plus_function = Virtual::MethodSource.create_method(:Integer,:plus , [Virtual::Integer] )
          plus_function.source.return_type = Virtual::Integer
          plus_function.source.receiver = Virtual::Integer
          plus_function.source.add_code Register::OperatorInstruction.new( plus_function, :add , 0 , 0 )
          return plus_function
        end
        # The conversion to base10 is quite a bit more complicated than i thought.
        # The bulk of it is in div10
        # We set up variables, do the devision and write the result to the string
        # then check if were done and recurse if neccessary
        # As we write before we recurse (save a push) we write the number backwards
        # arguments: string address , integer
        # def utoa context
        #   utoa_function = Virtual::MethodSource.create_method(:Integer ,:utoa ,  [ Virtual::Integer ] )
        #   function.source.return_type = Virtual::Integer
        #   function.source.receiver = Virtual::Integer
        #   return utoa_function
        #   # str_addr = utoa_function.receiver
        #   # number = utoa_function.args.first
        #   # remainder = utoa_function.new_local
        #   # Virtual::RegisterMachine.instance.div10( utoa_function , number  , remainder )
        #   # # make char out of digit (by using ascii encoding) 48 == "0"
        #   # utoa_function.instance_eval do
        #   #   add(  remainder , remainder , 48)
        #   #   strb( remainder, str_addr )
        #   #   sub(  str_addr,  str_addr ,  1 )
        #   #   cmp(  number ,  0 )
        #   #   callne( utoa_function  )
        #   # end
        #   # return utoa_function
        # end

        def putint context
          putint_function = Virtual::MethodSource.create_method(:Integer,:putint , [] )
          putint_function.source.return_type = Virtual::Integer
          putint_function.source.receiver = Virtual::Integer
          return putint_function
          # buffer = Parfait::Word.new("           ") # create a buffer
          # context.object_space.add_object buffer              # and save it (function local variable: a no no)
          # int = putint_function.receiver
          # moved_int = putint_function.new_local
          # utoa = context.object_space.get_class_by_name(:Object).resolve_method(:utoa)
          # putint_function.instance_eval do
          #   mov( moved_int ,  int )     # move arg up
          #   add( int ,  buffer ,nil )   # string to write to (add string address to pc)
          #   add( int , int ,  buffer.length - 3) # 3 for good measure , ahem.
          #   call( utoa )
          #   after = new_block("after_call")
          #   insert_at after
          #   # And now we "just" have to print it, using the write_stdout
          #   add( int ,  buffer , nil )   # string to write to
          #   mov( moved_int ,  buffer.length )
          # end
          # Virtual::RegisterMachine.instance.write_stdout(putint_function)
          # putint_function
        end

        # testing method, hand coded fibo, expects arg in receiver_register
        # result comes in return_register
        # a hand coded version of the fibonachi numbers
        # not my hand off course, found in the net http://www.peter-cockerell.net/aalp/html/ch-5.html
        def fibo context
          fibo_function = Virtual::MethodSource.create_method(:Integer,:fibo ,  [] )
          fibo_function.source.return_type = Virtual::Integer
          fibo_function.source.receiver = Virtual::Integer
          return fibo_function
          # result = fibo_function.return_type
          # int = fibo_function.receiver
          #
          # last = fibo_function.new_block("return")
          #
          # f1 = fibo_function.new_local
          # f2 = fibo_function.new_local
          #
          # fibo_function.instance_eval do
          #   cmp  int , 1
          #   mov( result, int , condition_code: :le)
          #   ble( last ) #branch to return, rather than return (as the original)
          #   mov f1 , 1        #set up initial values
          #   mov f2 , 0
          # end
          #
          # loop = fibo_function.new_block("loop")
          # fibo_function.insert_at loop
          #
          # fibo_function.instance_eval do #loop through
          #   add f1 , f1 , f2             # f1 = f1 + f2
          #   sub f2 , f1 , f2             # f2 = f1 -f2
          #   sub int ,  int , 1  # todo: set.. should do below cmp, but doesn't , set_update_status: 1
          #   cmp int , 1
          #   bne( loop )
          #   mov( result , f1 )
          # end
          #
          # fibo_function
        end
      end
      extend ClassMethods
    end
  end
end