118 lines
3.2 KiB
Ruby
118 lines
3.2 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_reader :symbol , :type , :value
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attr_accessor :builder
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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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# can't overload "=" , so use shift for it.
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# move the right side to the left. Left (this) is a RiscValue
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# right value may be
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# - constant (Parfait object) , resulting in a LoadConstant
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# - another RiscValue, resulting in a Transfer instruction
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# - an RValue, which gets procuced by the [] below
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def <<( load )
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puts "LOAD #{load}"
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case load
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when RValue
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raise "not yet"
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when Parfait::Object
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ins = Risc.load_constant("#{load.class} to #{self.type}" , load , self)
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when RiscValue
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ins = Risc.transfer("#{load.type} to #{self.type}" , load , self)
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else
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raise "not implemented"
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end
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builder.add_instruction(ins) if builder
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return ins
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end
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# just capture the values in an intermediary object (RValue)
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# The RValue then gets used in a RegToSlot ot SlotToReg, where
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# the values are unpacked to call Risc.reg_to_slot or Risc.slot_to_reg
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def []( index )
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RValue.new( self , index)
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end
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end
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# Just a struct, see comment for [] of RiscValue
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#
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class RValue
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attr_reader :register , :index
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def initialize(register, index)
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@register , @index = register , index
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end
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end
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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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end
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