81 lines
1.9 KiB
Ruby
81 lines
1.9 KiB
Ruby
module Register
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# RegisterReference is not the name for a register, "only" for a certain use of it.
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# In a way it is like a variable name, a storage location. The location is a register off course,
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# but which register can be changed, and _all_ instructions sharing the RegisterReference then
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# use that register
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# In other words a simple level of indirection, or change from value to reference sematics.
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class RegisterReference
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attr_accessor :symbol
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def initialize r
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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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@symbol = r
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end
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def self.convert something
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return something unless something.is_a? Symbol
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return something unless look_like_reg(something)
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return new(something)
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end
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def self.look_like_reg is_it
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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 != RegisterReference
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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 by = 1
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int = @symbol[1,3].to_i
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sym = "r#{int + by}".to_sym
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RegisterReference.new( sym )
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end
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SELF_REG = :r0
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MESSAGE_REG = :r1
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FRAME_REG = :r2
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NEW_MESSAGE_REG = :r3
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TMP_REG = :r4
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def self.self_reg
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new SELF_REG
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end
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def self.message_reg
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new MESSAGE_REG
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end
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def self.frame_reg
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new FRAME_REG
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end
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def self.new_message_reg
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new NEW_MESSAGE_REG
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end
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def self.tmp_reg
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new TMP_REG
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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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end
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