create return address as own class to hold return addresses

to distinguish from integer, which does not need adjusting

lib/parfait/integer.rb

@@ -49,6 +49,13 @@ module Parfait
     # :>, :>=, :<, :<=, :between?
   end
 
+  # Marker class. Same functionality as Integer
+  # (ie carrying an int, the return address)
+  #
+  # But the integer (address) needs to be adjusted by load address.
+  class ReturnAddress < Integer
+  end
+
   # adding other base classes in here for now:
   class FalseClass < Data4
     #FIXME: this is "just" for compilation

lib/risc/boot.rb

@@ -118,8 +118,8 @@ module Risc
     # superclasses other than default object
     def  super_class_names
        { Data4: :DataObject , Data8: :DataObject ,Data16: :DataObject ,
-         BinaryCode: :Data16 , Integer: :Data4, Word: :Data8 ,
-         Object: :BasicObject , List: :Data16}
+         BinaryCode: :Data16 , Integer: :Data4 , Word: :Data8 ,
+         Object: :BasicObject , List: :Data16 , ReturnAddress: :Integer}
     end
 
     # the function really just returns a constant (just avoiding the constant)
@@ -132,6 +132,7 @@ module Risc
                      return_address: :Integer, return_value: :Object,
                      caller: :Message ,        name: :Word ,     arguments: :NamedList },
           Integer: {next_integer: :Integer},
+          ReturnAddress: {next_integer: :Integer},
           DataObject: {},
           Data4: {},
           Data8: {},

lib/risc/instructions/label.rb

@@ -66,8 +66,7 @@ module Risc
   # if none was given
   def self.label( source , name , position = nil , nekst = nil)
     unless position
-      position = Parfait.object_space.get_integer
-      Risc.machine.add_constant(position)
+      position = Risc.machine.get_address
     end
     Label.new( source , name , position, nekst )
   end

lib/risc/machine.rb

@@ -20,6 +20,7 @@ module Risc
       @booted = false
       @risc_init = nil
       @constants = []
+      @next_address = nil
     end
     attr_reader  :constants , :cpu_init
     attr_reader  :booted , :translated
@@ -61,6 +62,17 @@ module Risc
       @constants << const
     end
 
+    # hand out a return address for use as constant the address is added
+    def get_address
+      10.times do # 10 for whole pages
+        @next_address = Parfait::ReturnAddress.new(0,@next_address)
+        add_constant( @next_address )
+      end unless @next_address
+      addr = @next_address
+      @next_address = @next_address.next_integer
+      addr
+    end
+
     # To create binaries, objects (and labels) need to have a position
     # (so objects can be loaded and branches know where to jump)
     #

lib/risc/text_writer.rb

@@ -148,8 +148,8 @@ module Risc
     def write_integer( int )
       write_ref_for( int.get_type )
       write_ref_for( int.next_integer )
-      @stream.write_signed_int_32( int.value )
-      @stream.write_signed_int_32( 0 )
+      write_ref_for( int.value )
+      write_ref_for( 0 )
       log.debug "Integer witten stream 0x#{@stream.length.to_s(16)}"
     end