245 lines
8.3 KiB
Ruby
245 lines
8.3 KiB
Ruby
module Risc
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# To create a binary, we need a so called Text element. Bad name for what is the code
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#
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# Binary code is already created by the Machine (by translating risc to arm to binary)
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#
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# This class serves to write all the objects of the machine (wich also contain the code)
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# into one stream or binary text object. This is then written to an ELF text section.
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#
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# A word about positions: The c world has a thing called position independent code, and
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# baically we follw that idea. Code (ie jumps and constant loads) are all relative.
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# But we have pointers. In C the linker takes care of bending those, we have to
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# do that ourselves, in write_ref. That's why we need the load adddess and basically
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# we just add it to pointers.
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class TextWriter
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include Util::Logging
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log_level :info
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def initialize(machine)
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@machine = machine
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end
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# objects must be written in same order as positioned by the machine, namely
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# - intial jump
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# - all objects
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# - all BinaryCode
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def write_as_string
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@stream = StringIO.new
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write_init(@machine.cpu_init)
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write_debug
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write_objects
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write_code
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log.debug "Assembled 0x#{stream_position.to_s(16)} bytes"
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return @stream.string
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end
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def sorted_objects
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@machine.object_positions.values.sort do |left , right|
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Position.get(left).at <=> Position.get(right).at
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end
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end
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# debugging loop to write out positions (in debug)
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def write_debug
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sorted_objects.each do |objekt|
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next if objekt.is_a?(Risc::Label)
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log.debug "Linked #{objekt.class}:0x#{objekt.object_id.to_s(16)} at #{Position.get(objekt)} / 0x#{objekt.padded_length.to_s(16)}"
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end
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end
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# Write all the objects in the order that they have been positioed
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def write_objects
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sorted_objects.each do |objekt|
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next if objekt.is_a? Risc::Label # ignore
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next if objekt.is_a? Parfait::BinaryCode # ignore
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write_any( objekt )
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end
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end
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# Write the BinaryCode objects of all methods to stream.
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# Really like any other object, it's just about the ordering
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def write_code
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Parfait.object_space.each_type do |type|
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type.each_method do |method|
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method.each_binary do |code|
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write_any(code)
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end
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end
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end
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end
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# Write any object just logs a bit and passes to write_any_out
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def write_any( obj )
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write_any_log( obj , "Write")
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if stream_position != Position.get(obj).at
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raise "Write #{obj.class}:0x#{obj.object_id.to_s(16)} at 0x#{stream_position.to_s(16)} not #{Position.get(obj)}"
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end
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write_any_out(obj)
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write_any_log( obj , "Wrote")
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Position.get(obj)
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end
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def write_any_log( obj , at)
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log.debug "#{at} #{obj.class}:0x#{obj.object_id.to_s(16)} at stream 0x#{stream_position.to_s(16)} pos:#{Position.get(obj)} , len:0x#{obj.padded_length.to_s(16)}"
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end
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# Most objects are the same and get passed to write_object
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# But Strings and BinaryCode write out binary, so they have different methods (for now)
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def write_any_out(obj)
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case obj
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when Parfait::Word, Symbol
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write_String obj
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when Parfait::BinaryCode
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write_BinaryCode( obj )
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when Parfait::ReturnAddress
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write_return_address( obj )
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when Parfait::Integer
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write_integer( obj )
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when Parfait::Data4
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write_data4( obj )
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else
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write_object( obj )
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end
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end
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# write type of the instance, and the variables that are passed
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# variables ar values, ie int or refs. For refs the object needs to save the object first
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def write_object( object )
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write_object_check(object)
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obj_written = write_object_variables(object)
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log.debug "instances=#{object.get_instance_variables.inspect} mem_len=0x#{object.padded_length.to_s(16)}"
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indexed_written = write_object_indexed(object)
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log.debug "type #{obj_written} , total #{obj_written + indexed_written} (array #{indexed_written})"
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log.debug "Len = 0x#{object.get_length.to_s(16)} , inst =0x#{object.get_type.instance_length.to_s(16)}" if object.is_a? Parfait::Type
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pad_after( obj_written + indexed_written )
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Position.get(object)
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end
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def write_object_check(object)
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log.debug "Write object #{object.class} #{object.inspect[0..100]}"
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#Only initially created codes are collected. Binary_init and method "tails" not
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if !@machine.object_positions.has_key?(object) and !object.is_a?(Parfait::BinaryCode)
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log.debug "Object at 0x#{Position.get(object).to_s(16)}:#{object.get_type()}"
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raise "Object(0x#{object.object_id.to_s(16)}) not linked #{object.inspect}"
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end
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end
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def write_object_indexed(object)
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written = 0
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if( object.is_a? Parfait::List)
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object.each do |inst|
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write_ref_for(inst)
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written += 4
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end
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end
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written
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end
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def write_object_variables(object)
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written = 0 # compensate for the "secret" marker
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object.get_instance_variables.each do |var|
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inst = object.get_instance_variable(var)
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#puts "Nil for #{object.class}.#{var}" unless inst
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inst = nil if [:cpu_instructions , :risc_instructions].include?(var)
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write_ref_for(inst)
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written += 4
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end
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written
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end
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def write_return_address( addr )
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write_ref_for( addr.get_type )
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write_ref_for( addr.next_integer )
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write_ref_for( addr.value + @machine.platform.loaded_at )
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write_ref_for( 0 )
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log.debug "Integer witten stream 0x#{@stream.length.to_s(16)}"
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end
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def write_integer( int )
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write_ref_for( int.get_type )
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write_ref_for( int.next_integer )
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write_ref_for( int.value )
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write_ref_for( 0 )
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log.debug "Integer witten stream 0x#{@stream.length.to_s(16)}"
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end
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def write_data4( code )
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write_ref_for( code.get_type )
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write_ref_for( code.get_type )
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write_ref_for( code.get_type )
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write_ref_for( code.get_type )
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log.debug "Data4 witten stream 0x#{@stream.length.to_s(16)}"
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end
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# first jump,
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def write_init( cpu_init )
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cpu_init.assemble(@stream)
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@stream.write_unsigned_int_8(0) until @machine.platform.padding == stream_position
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log.debug "Init witten stream 0x#{@stream.length.to_s(16)}"
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end
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def write_BinaryCode( code )
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write_ref_for( code.get_type )
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write_ref_for( code.next )
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code.each_word do |word|
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@stream.write_unsigned_int_32( word || 0 )
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end
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log.debug "Code16 witten stream 0x#{@stream.length.to_s(16)}"
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end
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def write_String( string )
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if string.is_a? Parfait::Word
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str = string.to_string
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raise "length mismatch #{str.length} != #{string.char_length}" if str.length != string.char_length
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end
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str = string.to_s if string.is_a? Symbol
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log.debug "#{string.class} is #{string} at 0x#{Position.get(string)} length 0x#{string.length.to_s(16)}"
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write_checked_string(string , str)
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end
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def write_checked_string(string, str)
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write_ref_for( string.get_type ) #ref
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@stream.write_signed_int_32( str.length ) #int
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@stream.write str
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pad_after(str.length + 8 ) # type , length
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log.debug "String (0x#{string.length.to_s(16)}) stream 0x#{@stream.length.to_s(16)}"
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end
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def write_Symbol(sym)
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return write_String(sym)
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end
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private
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# write means we write the resulting address straight into the assembler stream
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# object means the object of which we write the address
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def write_ref_for object
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case object
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when nil
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@stream.write_signed_int_32(0)
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when Fixnum
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@stream.write_signed_int_32(object)
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else
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@stream.write_signed_int_32(Position.get(object) + @machine.platform.loaded_at)
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end
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end
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# pad_after is always in bytes and pads (writes 0's) up to the next 8 word boundary
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def pad_after( length )
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before = stream_position
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pad = Padding.padding_for(length)
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pad.times do
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@stream.write_unsigned_int_8(0)
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end
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after = stream_position
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log.debug "padded 0x#{length.to_s(16)} with 0x#{pad.to_s(16)} stream #{before.to_s(16)}/#{after.to_s(16)}"
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end
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# return the stream length as hex
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def stream_position
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@stream.length
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end
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end
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end
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