fix arm (assembled) indexing

by having a dummy 0 index in salaam. when assembled

Gemfile.lock

@@ -1,6 +1,6 @@
 GIT
   remote: git://github.com/salama/salama-arm.git
-  revision: 00b175d354046a6228f66a980822eae974ca807a
+  revision: 72fcf371bc42279676533142c82e34713e77ea75
   specs:
     salama-arm (0.3.0)
 

lib/arm/translator.rb

@@ -17,12 +17,11 @@ module Arm
 
     # arm indexes are
     #  in bytes, so *4
-    #  0 based , so -1
+    # if an instruction is passed in we get the index with index function
-    # if an instruction is passed in we ge the index with inex function
     def arm_index index
       index = index.index if index.is_a?(Register::Instruction)
       raise "index error 0" if index == 0
-      (index - 1) * 4
+      index * 4
     end
     # Arm stores the return address in a register (not on the stack)
     # The register is called link , or lr for short .

lib/register/assembler.rb

@@ -13,6 +13,8 @@ module Register
     include Logging
     log_level :info
 
+    MARKER = 0xA51AF00D
+
     def initialize machine
       @machine = machine
       @load_at = 0x8054 # this is linux/arm
@@ -35,7 +37,7 @@ module Register
       @machine.objects.each do |id , objekt|
         next unless objekt.is_a? Parfait::Method
         objekt.binary.position = at
-        objekt.instructions.set_position at + 8 # BinaryCode header
+        objekt.instructions.set_position at + 12 # BinaryCode header
         len = objekt.instructions.total_byte_length
         log.debug "CODE #{objekt.name} at #{objekt.binary.position} len: #{len}"
         objekt.binary.set_length(len , 0)
@@ -137,7 +139,8 @@ module Register
       unless @machine.objects.has_key? object.object_id
         raise "Object(#{object.object_id}) not linked #{object.inspect}"
       end
-      written = 0
+      @stream.write_sint32( MARKER  )
+      written = 0 # compensate for the "secrect" marker
       object.get_instance_variables.each do |var|
         inst = object.get_instance_variable(var)
         #puts "Nil for #{object.class}.#{var}" unless inst
@@ -154,7 +157,7 @@ module Register
       end
       log.debug "layout #{lay_len} , total #{written} (array #{written - lay_len})"
       log.debug "Len = #{object.get_length} , inst = #{object.get_layout.instance_length}" if object.is_a? Parfait::Layout
-      pad_after( written )
+      pad_after( written  )
       object.position
     end
 
@@ -169,10 +172,11 @@ module Register
       end
       str = string.to_s if string.is_a? Symbol
       log.debug "#{string.class} is #{string} at #{string.position} length #{string.length}"
+      @stream.write_sint32( MARKER  )
       write_ref_for( string.get_layout ) #ref
       @stream.write_sint32( str.length  ) #int
       @stream.write str
-      pad_after(str.length + 8)
+      pad_after(str.length + 8 ) # layout , length   *4 == 12
       log.debug "String (#{string.length}) stream #{@stream.length}"
     end
 
@@ -198,7 +202,7 @@ module Register
     # pad_after is always in bytes and pads (writes 0's) up to the next 8 word boundary
     def pad_after length
       before = stream_position
-      pad = padding_for(length)
+      pad = padding_for(length) - 4  # four is for the MARKER we write
       pad.times do
         @stream.write_uint8(0)
       end

lib/register/padding.rb

@@ -1,9 +1,10 @@
 
 module Padding
 
-  # objects only come in lengths of multiple of 8 words
+  # objects only come in lengths of multiple of 8 words / 32 bytes
+  # and there is a "hidden" 1 word that is used for debug/check memory corruption
   def padded len
-    a = 32 * (1 + (len - 1)/32 )
+    a = 32 * (1 + (len + 3)/32 )
     #puts "#{a} for #{len}"
     a
   end

test/register/test_padding.rb

@@ -10,17 +10,17 @@ class TestPadding < MiniTest::Test
     @pad = Padded.new
   end
   def test_small
-    [6,27,28,32].each do |p|
+    [6,27,28].each do |p|
       assert_equal 32 , @pad.padded(p) , "Expecting 32 for #{p}"
     end
   end
   def test_medium
-    [33,40,57,60,64].each do |p|
+    [29,33,40,57,60].each do |p|
       assert_equal 64 , @pad.padded(p) , "Expecting 64 for #{p}"
     end
   end
   def test_large
-    [65,88].each do |p|
+    [61,65,88].each do |p|
       assert_equal 96 , @pad.padded(p) , "Expecting 96 for #{p}"
     end
   end