APX Virtual Machine v1

APX virtual machine currently implemented in py-apx. Note that qt-apx implements an even earlier version that was never documented. (Implementation needs to be updated).

Instructions

Opcode Number Opcode Name Size Opcode arguments (additional bytes) Description
0 NOP 1   No operation
1 PACK_PROG_HDR 5
  1. progLenType0 (LSB)
  2. progLenType1
  3. progLenType2
  4. progLenType3 (MSB)
 pack program header
2 UNPACK_PROG_HDR 5
  1. progLenType0 (LSB)
  2. progLenType1
  3. progLenType2
  4. progLenType3 (MSB)
 pack program header
3 PACK_U8 1   pack single uint8
4 PACK_U16 1   pack single uint16
5 PACK_U32 1   pack single uint32
6 PACK_S8 1   pack single sint8
7 PACK_S16 1   pack single sint16
8 PACK_S32 1   pack single sint32
9 PACK_STR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack string
10 PACK_U8AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack uint8 array
11 PACK_U16AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack uint16 array
12 PACK_U32AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack uint32 array
13 PACK_S8AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack uint8 array
14 PACK_S16AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack uint16 array
15 PACK_S32AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 pack uint32 array
16 UNPACK_U8 1   unpack single uint8
17 UNPACK_U16 1   unpack single uint16
18 UNPACK_U32 1   unpack single uint32
19 UNPACK_S8 1   unpack single sint8
20 UNPACK_S16 1   unpack single sint16
21 UNPACK_S32 1   unpack single sint32
22 UNPPACK_STR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack string
23 UNPACK_U8AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack uint8 array
24 UNPACK_U16AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack uint16 array
25 UNPACK_U32AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack uint32 array
26 UNPACK_S8AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack sint8 array
27 UNPACK_S16AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack sint16 array
28 UNPACK_S32AR 3
  1. LengthByte0(LSB)
  2. LengthByte1(MSB)
 unpack sint32 array
29 RECORD_ENTER 1   record inside of record
30 RECORD_SELECT VAR null-terminated utf-8 string name of record element
31 RECORD_LEAVE 1    
32 ARRAY_ENTER 1   Used for array of records
33 ARRAY_LEAVE 1    

APX Variants

Variants are variables that can store values of different types. They are supported in one way or another in most programming languages.

Types of variants:

  • Scalars (integers, strings)
  • Lists (list of variants)
  • Maps (key-value map to variants)

Variant types are identified internally using integers according to the following table:

Value Name
-1 VTYPE_INVALID
0 VTYPE_SCALAR
1 VTYPE_LIST
2 VTYPE_MAP

Variant Language Mapping

Each APX implementation maps the APX variant according to what is available to the language.

Programming Language VTYPE_SCALAR VTYPE_LIST VTYPE_MAP
C (with dtl_type library) dtl_sv_t dtl_av_t dtl_hv_t
C++ (with Qt variants) QVariant QVariantList QVariantMap
Python (int, str) list dict
Visual Basic (Excel) Variant Variant Scripting.Dictionary