Adobe ActionScript Virtual Machine 2 (AVM2) Overview 3
Contents
1 Introduction............................................................................................................................ 5
1.1 Concepts................................................................................................................................................5
2 The structure of the ActionScript Virtual Machine .............................................................. 7
2.1 Constant values..................................................................................................................................... 7
2.2 Virtual machine overview..................................................................................................................... 7
2.3 Names ....................................................................................................................................................8
2.3.1 QName (Qualified Name)......................................................................................................8
2.3.2 RTQName (Runtime Qualified Name) ................................................................................8
2.3.3 RTQNameL (Runtime Qualified Name Late).....................................................................9
2.3.4 Multiname (Multiple Namespace Name) ............................................................................9
2.3.5 MultinameL (Multiple Namespace Name Late)................................................................. 9
2.3.6 Resolving multinames ......................................................................................................... 10
2.4 Method invocation notes ................................................................................................................... 10
2.5 Instruction set summary.......................................................................................................................11
2.5.1 Load and store instructions ..................................................................................................11
2.5.2 Arithmetic instructions...........................................................................................................11
2.5.3 Bit manipulation instructions ................................................................................................11
2.5.4 Type conversion instructions................................................................................................11
2.5.5 Object creation and manipulation instructions ................................................................ 12
2.5.6 Stack management instructions ........................................................................................ 12
2.5.7 Control transfer instructions ............................................................................................... 12
2.5.8 Function invocation and return instructions..................................................................... 12
2.5.9 Exception instructions......................................................................................................... 12
2.5.10 Debugging instructions ....................................................................................................... 13
3 Loading, linking, verification, and execution.......................................................................14
3.1 Overview .............................................................................................................................................. 14
3.2 Loading and linking ............................................................................................................................ 14
3.3 Execution ............................................................................................................................................. 15
3.3.1 Program invocation and exit............................................................................................... 15
3.3.2 Class initialization................................................................................................................. 15
3.3.3 Method entry......................................................................................................................... 15
3.3.4 Execution mechanics .......................................................................................................... 16
3.3.5 Calling and returning............................................................................................................ 16
3.3.6 Exception handling .............................................................................................................. 16
3.4 Verification........................................................................................................................................... 16
4 The ActionScript Byte Code (abc) format...........................................................................18
4.1 Primitive data types .............................................................................................................................18
4.2 abcFile.................................................................................................................................................. 19
4.3 Constant pool ..................................................................................................................................... 20
4.4 String .................................................................................................................................................... 21
4.4.1 Namespace.......................................................................................................................... 22
4.4.2 Namespace set.................................................................................................................... 22
4.4.3 Multiname............................................................................................................................. 23
4.5 Method signature............................................................................................................................... 24
4.5.1 Optional parameters ........................................................................................................... 25
4.5.2 Parameter names.................................................................................................................27
4.6 metadata_info......................................................................................................................................27
4.7 Instance............................................................................................................................................... 28
4.8 Trait...................................................................................................................................................... 29
4.8.1 Summary of trait types ....................................................................................................... 29
4.8.2 Slot and const traits ............................................................................................................ 30
4.8.3 Class traits............................................................................................................................ 30
4.8.4 Function traits....................................................................................................................... 31
