132 lines
3.8 KiB
Ruby
132 lines
3.8 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( reg , type , value = nil)
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raise "not reg #{reg}" unless self.class.look_like_reg( reg )
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@type = type
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@symbol = reg
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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 > 11
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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 rxf_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, resulting in an SlotToReg
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def <<( right )
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case right
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when Parfait::Object , Symbol
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ins = Risc.load_constant("#{right.class} to #{self.type}" , right , self)
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when RiscValue
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ins = Risc.transfer("#{right.type} to #{self.type}" , right , self)
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when RValue
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ins = Risc.slot_to_reg("#{right.register.type}[#{right.index}] -> #{self.type}" , right.register , right.index , self)
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else
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raise "not implemented for #{right.class}:#{right}"
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end
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builder.add_code(ins) if builder
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return ins
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end
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def -( right )
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raise "operators only on registers, not #{right.class}" unless right.is_a? RiscValue
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op = Risc.op("#{self.type} - #{right.type}", :- , self , right )
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builder.add_code(op) if builder
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op
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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 , builder)
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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 , :builder
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def initialize(register, index , builder)
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@register , @index , @builder = register , index , builder
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end
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# fullfil the objects purpose by creating a RegToSlot instruction from
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# itself (the slot) and the register given
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def <<( reg )
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raise "not reg #{reg}" unless reg.is_a?(RiscValue)
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reg_to_slot = Risc.reg_to_slot("#{reg.type} -> #{register.type}[#{index}]" , reg , register, index)
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builder.add_code(reg_to_slot) if builder
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reg_to_slot
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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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