65 lines
1.8 KiB
Ruby
65 lines
1.8 KiB
Ruby
module Risc
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# just moved compilers register related stuff here
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#
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# Allocator keeps a list of registers and passes them out
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# upon request. they must be returned in order
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class Allocator
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def initialize( compiler , platform)
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@compiler = compiler
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@platform = platform
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@regs = []
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reset_regs
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end
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attr_reader :regs , :compiler , :platform
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def regs_empty?
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@regs.empty?
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end
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def add_reg(reg)
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raise "not reg #{reg.class}" unless reg.is_a?(RegisterValue)
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@regs << reg
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end
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def pop
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@regs.pop
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end
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def clear_regs
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@regs.clear
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end
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# require a (temporary) register. code must give this back with release_reg
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# Second extra parameter may give extra info about the value, see RegisterValue
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def use_reg( type , extra = {} )
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raise "Not type #{type.inspect}:#{type.class}" unless type.is_a?(Symbol) or type.is_a?(Parfait::Type)
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if @regs.empty?
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reg = Risc.tmp_reg(type , extra)
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else
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reg = @regs.last.next_reg_use(type , extra)
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end
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@regs << reg
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return reg
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end
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def copy( reg , source )
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copied = use_reg reg.type
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add_code Register.transfer( source , reg , copied )
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copied
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end
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# releasing a register (accuired by use_reg) makes it available for use again
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# thus avoiding possibly using too many registers
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def release_reg( reg )
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last = @regs.pop
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raise "released register in wrong order, expect #{last} but was #{reg}" if reg != last
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end
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# reset the registers to be used. Start at r4 for next usage.
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# Every statement starts with this, meaning each statement may use all registers, but none
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# get saved. Statements have affect on objects.
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def reset_regs
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@regs.clear
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end
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end
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end
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