130 lines
4.1 KiB
Ruby
130 lines
4.1 KiB
Ruby
module Risc
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# RiscValue is like a variable name, a storage location. The location is a register off course.
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class RiscValue
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attr_accessor :symbol , :type , :value
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def initialize r , type , value = nil
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raise "wrong type for register init #{r}" unless r.is_a? Symbol
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raise "double r #{r}" if r.to_s[0,1] == "rr"
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raise "not reg #{r}" unless self.class.look_like_reg r
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@type = type
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@symbol = r
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@value = value
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end
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def to_s
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s = "#{symbol}:#{type}"
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s += ":#{value}" if value
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s
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end
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def reg_no
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@symbol.to_s[1 .. -1].to_i
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end
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def self.look_like_reg is_it
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return true if is_it.is_a? RiscValue
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return false unless is_it.is_a? Symbol
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if( [:lr , :pc].include? is_it )
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return true
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end
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if( (is_it.to_s.length <= 3) and (is_it.to_s[0] == "r"))
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# could tighten this by checking that the rest is a number
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return true
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end
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return false
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end
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def == other
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return false if other.nil?
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return false if other.class != RiscValue
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symbol == other.symbol
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end
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#helper method to calculate with register symbols
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def next_reg_use( type , value = nil )
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int = @symbol[1,3].to_i
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raise "No more registers #{self}" if int > 8
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sym = "r#{int + 1}".to_sym
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RiscValue.new( sym , type, value)
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end
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def sof_reference_name
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@symbol
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end
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end
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# Here we define the mapping from virtual machine objects, to register machine registers
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#
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# The register we use to store the current message object is :r0
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def self.message_reg
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RiscValue.new :r0 , :Message
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end
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# The register we use to store the new message object is :r3
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# The new message is the one being built, to be sent
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def self.new_message_reg
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RiscValue.new :r1 , :Message
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end
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# The first scratch register. There is a next_reg_use to get a next and next.
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# Current thinking is that scratch is schatch between instructions
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def self.tmp_reg( type , value = nil)
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RiscValue.new :r1 , type , value
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end
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# The first arg is a class name (possibly lowercase) and the second an instance variable name.
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# By looking up the class and the type for that class, we can resolve the instance
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# variable name to an index.
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# The class can be mapped to a register, and so we get a memory address (reg+index)
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# Third arg, compiler, is only needed to resolve receiver/arguments/frame
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def self.resolve_to_index(object , variable_name ,compiler = nil)
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return variable_name if variable_name.is_a?(Integer) or variable_name.is_a?(RiscValue)
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object = object.type if object.is_a?(RiscValue)
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case object
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when :frame
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type = compiler.method.frame_type
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when :message , :next_message , :caller
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type = Parfait.object_space.get_class_by_name(:Message).instance_type
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when :arguments
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type = compiler.method.arguments_type
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when :receiver
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type = compiler.method.for_type
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when Parfait::Object
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type = Parfait.object_space.get_class_by_name( object.class.name.split("::").last.to_sym).instance_type
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when Symbol
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clazz = Parfait.object_space.get_class_by_name(object)
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raise "Not implemented/found object #{object}:#{object.class}" unless clazz
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type = clazz.instance_type
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else
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raise "Not implemented/found object #{object}:#{object.class}"
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end
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index = type.variable_index(variable_name)
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raise "Index not found for #{variable_name} in #{object} of type #{type}" unless index
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return index
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end
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# if a symbol is given, it may be the message or the new_message.
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# These are mapped to register references.
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# The valid symbols (:message,:new_message) are the same that are returned
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# by the slots. All data (at any time) is in one of the instance variables of these two
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# objects. Risc defines module methods with the same names (and _reg)
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def self.resolve_to_register( reference )
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return reference if reference.is_a?(RiscValue)
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case reference
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when :message
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return message_reg
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when :new_message
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return new_message_reg
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else
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raise "not recognized register reference #{reference} #{reference.class}"
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end
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end
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end
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