n65/lib/n65/directives/org.rb

# frozen_string_literal: true

require_relative '../instruction_base'

module N65
  # This is an .org directive
  class Org < InstructionBase
    attr_reader :address

    def self.parse(line)
      match_data = line.match(/^\.org\s+\$([0-9A-Fa-f]{4})$/)
      return nil if match_data.nil?

      address = match_data[1].to_i(16)
      Org.new(address)
    end

    # Initialized with address to switch to
    def initialize(address)
      @address = address
    end

    # Exec this directive on the assembler
    def exec(assembler)
      assembler.program_counter = address
    end

    # Display
    def to_s
      if @address <= 0xff
        '.org $%2.X' % @address
      else
        '.org $%4.X' % @address
      end
    end
  end
end