47 lines
1.6 KiB
Ruby
47 lines
1.6 KiB
Ruby
module SlotMachine
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class Comparison < Macro
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def self.operators
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[:<, :>, :>=, :<=]
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end
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attr_reader :operator
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def initialize(name , operator)
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super(name)
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raise "unsuported operator :#{operator}:#{operator.class}:" unless self.class.operators.include?(operator)
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@operator = operator
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end
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# basically use subtract to subtract left from right (or right from left)
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# and load true_object in the true branch and false_object in the false
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# for the case of =, as in <= or >= we also do not check for zero
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def to_risc(compiler)
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builder = compiler.builder(compiler.source)
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operator = @operator # make accessible in block
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false_label = Risc.label("false" , "false_label_#{object_id}")
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merge_label = Risc.label("merge" , "merge_label_#{object_id}")
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result = Risc::RegisterValue.new(:result , :Object)
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builder.build do
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left = message[:receiver].reduce_int(false) #false == hack
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right = message[:arg1].reduce_int(false)
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if(operator.to_s.start_with?('<') )
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right.op :- , left
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else
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left.op :- , right
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end
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if_minus false_label
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if_zero( false_label ) if operator.to_s.length == 1
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add_code Risc::LoadConstant.new(to_s , Parfait.object_space.true_object, result)
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branch merge_label
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add_code false_label
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add_code Risc::LoadConstant.new(to_s , Parfait.object_space.false_object, result)
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add_code merge_label
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message[:return_value] << result
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end
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return compiler
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end
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end
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end
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