n65/lib/n65/directives/org.rb

48 lines
808 B
Ruby

require_relative '../instruction_base'
module N65
####
## This is an .org directive
class Org < InstructionBase
attr_reader :address
####
## Try to parse an .org statement
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