module Register

  # GetSlot moves data into a register from memory.
  # SetSlot moves data into memory from a register.
  # Both use a base memory (a register)

  # While the virtual machine has only one instruction (Set) to move data between slots,
  # the register has two, namely GetSlot and SetSlot
  #
  # This is because that is what cpu's can do. In programming terms this would be accessing
  #  an element in an array, in the case of GetSlot setting the value in the array.

  # btw: to move data between registers, use RegisterTransfer

  class GetSlot < Instruction

    # If you had a c array and index offset
    # the instruction would do register = array[index]
    # The arguments are in the order that makes sense for the Instruciton name
    # So GetSlot means the slot (array and index) moves to the register (last argument)
    def initialize array , index , register
      @register = register
      @array = array
      @index = index
    end
    attr_accessor :register , :array , :index
  end
end