diff --git a/lib/arm/instructions/stack_instruction.rb b/lib/arm/instructions/stack_instruction.rb
index 491f65e1..4b8079a8 100644
--- a/lib/arm/instructions/stack_instruction.rb
+++ b/lib/arm/instructions/stack_instruction.rb
@@ -57,7 +57,7 @@ module Arm
     end
 
     def to_s
-      "#{opcode} [#{@first.join(',') }] #{super}"
+      "#{opcode} [#{@first.join(', ') }] #{super}"
     end
   end
 
diff --git a/lib/mom/instruction/slot_definition.rb b/lib/mom/instruction/slot_definition.rb
index a8167836..9a3a3770 100644
--- a/lib/mom/instruction/slot_definition.rb
+++ b/lib/mom/instruction/slot_definition.rb
@@ -30,7 +30,7 @@ module Mom
 
     def to_s
       names = [known_name] + @slots
-      "[#{names.join(',')}]"
+      "[#{names.join(', ')}]"
     end
 
     def known_name
diff --git a/lib/risc/instructions/branch.rb b/lib/risc/instructions/branch.rb
index 4c9f53e5..0b534537 100644
--- a/lib/risc/instructions/branch.rb
+++ b/lib/risc/instructions/branch.rb
@@ -16,6 +16,7 @@ module Risc
         str = label.name
       when Parfait::BinaryCode
         str = "Code"
+        str += ":#{Position.get(label)}" if Position.set?(label)
       else
         str = "(no label)"
       end
diff --git a/lib/risc/interpreter.rb b/lib/risc/interpreter.rb
index 33355899..8d2c375e 100644
--- a/lib/risc/interpreter.rb
+++ b/lib/risc/interpreter.rb
@@ -32,7 +32,8 @@ module Risc
       @linker = linker
     end
 
-    def start_program
+    def start_program(linker = nil)
+      @linker = linker || @linker
       initialize(@linker)
       init = @linker.cpu_init
       set_state(:running)
@@ -115,14 +116,15 @@ module Risc
     # Instruction interpretation starts here
     def execute_DynamicJump
       method =  get_register(@instruction.register)
-      set_pc( Position.get(method.cpu_instructions).at )
+      pos = Position.get(method.binary).at + Parfait::BinaryCode.byte_offset
+      set_pc( pos )
       false
     end
     def execute_Branch
       label = @instruction.label
       pos = Position.get(label).at
       pos += Parfait::BinaryCode.byte_offset if label.is_a?(Parfait::BinaryCode)
-      set_pc pos
+      set_pc( pos )
       false
     end
 
diff --git a/lib/vool/send_statement.rb b/lib/vool/send_statement.rb
index 53c2a955..337972a9 100644
--- a/lib/vool/send_statement.rb
+++ b/lib/vool/send_statement.rb
@@ -52,7 +52,7 @@ module Vool
     end
 
     def to_s
-      "#{receiver}.#{name}(#{arguments.join(',')})"
+      "#{receiver}.#{name}(#{arguments.join(', ')})"
     end
     def each(&block)
       block.call(self)
diff --git a/lib/vool/yield_statement.rb b/lib/vool/yield_statement.rb
index 2ef145dc..48ced6ad 100644
--- a/lib/vool/yield_statement.rb
+++ b/lib/vool/yield_statement.rb
@@ -33,7 +33,7 @@ module Vool
     end
 
     def to_s
-      "#{receiver}.#{name}(#{arguments.join(',')})"
+      "#{receiver}.#{name}(#{arguments.join(', ')})"
     end
     def each(&block)
       block.call(self)