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68 lines
2.0 KiB
Ruby
68 lines
2.0 KiB
Ruby
# frozen_string_literal: true
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module N65
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require_relative 'instruction'
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require_relative 'directives/ines_header'
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require_relative 'directives/org'
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require_relative 'directives/segment'
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require_relative 'directives/incbin'
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require_relative 'directives/inc'
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require_relative 'directives/dw'
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require_relative 'directives/bytes'
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require_relative 'directives/ascii'
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require_relative 'directives/label'
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require_relative 'directives/enter_scope'
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require_relative 'directives/exit_scope'
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require_relative 'directives/space'
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# This class determines what sort of line of code we
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# are dealing with, parses one line, and returns an
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# object deriving from InstructionBase
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class Parser
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class CannotParse < StandardError; end
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DIRECTIVES = [INESHeader, Org, Segment, IncBin, Inc, DW, Bytes, ASCII, EnterScope, ExitScope, Space].freeze
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# Parses a line of program source into an object
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# deriving from base class InstructionBase
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def self.parse(line)
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sanitized = sanitize_line(line)
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return nil if sanitized.empty?
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# First check to see if we have a label.
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label = Label.parse(sanitized)
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return label unless label.nil?
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# Now check if we have a directive
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directive = parse_directive(sanitized)
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return directive unless directive.nil?
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# Now, surely it is an asm instruction?
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instruction = Instruction.parse(sanitized)
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return instruction unless instruction.nil?
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# Guess not, we have no idea
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raise(CannotParse, sanitized)
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end
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# Sanitize one line of program source
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def self.sanitize_line(line)
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code = line.split(';').first || ''
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code.strip.chomp
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end
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private_class_method :sanitize_line
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## Try to Parse a directive
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def self.parse_directive(line)
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if line.start_with?('.')
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DIRECTIVES.each do |directive|
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object = directive.parse(line)
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return object unless object.nil?
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end
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end
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nil
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end
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private_class_method :parse_directive
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end
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end
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