Torsten Rüger
31c8a0aac5
That sort of removes the last horrible code. Surely can still be improved, but mostly oo now
61 lines
2.6 KiB
Ruby
61 lines
2.6 KiB
Ruby
module SlotMachine
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# SlotLoad is for moving data into a slot, either from another slot, or constant
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# A Slot is basically an instance variable, but it must be of known type
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#
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# The value loaded (the right hand side) can be a constant (SlotMachine::Constant) or come from
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# another Slot (SlotDefinition)
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#
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# The Slot on the left hand side is always a SlotDefinition.
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# The only known object (*) for the left side is the current message, which is a bit like
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# the oo version of a Stack (Stack Register, Frame Pointer, ..)
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# (* off course all class objects are global, and so they are allowed too)
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#
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# A maybe not immediately obvious corrolar of this design is the total absence of
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# general external instance variable accessors. Ie only inside an object's functions
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# can a method access instance variables, because only inside the method is the type
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# guaranteed.
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# From the outside a send is neccessary, both for get and set, (which goes through the method
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# resolution and guarantees the correct method for a type), in other words perfect data hiding.
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#
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# @left: A SlotDefinition, or an array that can be passed to the constructor of the
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# SlotDefinition (see there)
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#
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# @right: A SlotDefinition with slots or a SlotMachine::Constant
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# original_source: optinally another slot_machine instruction that will be passed down
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# to created risc instructions. (Because SlotLoad is often used internally)
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class SlotLoad < Instruction
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attr_reader :left , :right , :original_source
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def initialize(source , left , right, original_source = nil)
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super(source)
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@left , @right = left , right
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@left = SlotDefinition.for(@left.shift , @left) if @left.is_a? Array
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@right = SlotDefinition.for(@right.shift , @right) if @right.is_a? Array
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raise "right not SlotMachine, #{@right.to_s}" unless @right.is_a?( SlotDefinition )
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raise "left not SlotMachine, #{@left.to_s}" unless @left.is_a?( SlotDefinition )
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@original_source = original_source || self
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end
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def to_s
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"SlotLoad #{right} -> #{left}"
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end
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# resolve the SlotLoad to the respective risc Instructions.
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# calls sym_to_risc for most (symbols), and ConstantLoad for CacheEntry
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# after loading the right into register
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def to_risc(compiler)
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const_reg = @right.to_register(compiler , original_source)
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@left.reduce_and_load(const_reg , compiler , original_source )
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compiler.reset_regs
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end
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end
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end
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require_relative "slot_definition"
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require_relative "message_definition"
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require_relative "constant_definition"
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require_relative "object_definition"
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