SCPL 4.1 vm instructions:

opcode  tier    name    description

0x00 move   copies operand 1 to operand 2
0x01 1 call   runs sysfunc of operand
0x02 goout  goes out of current object
0x03 goin   goes into operand
0x04 pop    pops top of datastack
0x05 3 callif   runs sysfunc of operand if <top of datastack>.Cgetattr<bool>("content") is true

0x06 rem    stores value on datastack onto secondary stack
0x07 recall loads value from secondary stack onto datastack

0x08 4 while  executes operand while top of datastack is 1.
--UNAVAIL 0x09 2 try    executes operand and pushes an VMSTAT object onto datastack
0x0A ret    exits out of code which has the same or greater tier than specified
0x0B exec   executes given bytecode
--UNAVAIL 0x0C throw  throws exception with given string as message

0xFF DEBUG  Used by tests. logs <operand>.Cgetattr<std::string>("content")

-- UNAVAIL: Tier system currently unavailable.

operands:

0x00 getempty   returns an plain variable
0x01 int        creates an integer variable
0x02 float      creates an float variable
0x03 string     creates an string variable (null terminated)
0x04 list       creates an list variable
0x05 map        creates an map variable
0x06 bytearray  creates an bytearray variable

0x10 llvar      loads specified local variable
0x11 slvar      same as llvar except if it doesnt exist, creates one
0x12 lgvar      loads specified global variable
0x13 sgvar      same as lgvar except if it doesnt exist, creates one

0x20 ntdata     loads new empty variable ontop of datastack (and returns it)
0x21 tdata      loads top of datastack
0x22 tpdata     loads top of datastack and pops it off

0x30 lattr      loads specified attribute of current variable
0x31 sattr      same as lattr except if it doesnt exist, creates the attribute

0xFF marker     special marker for map, list and bytearray (cant be used with instructions.)

operand specification:

operand handler must return SCPLVARPTR
operand handler must be registered to work
handler must register with an op_handler ptr.

bytecode file (scbc) header specification:

at beginning of an scbc file
normal string, simply null terminated.
everything is treated as an string until 0xFF comes up.
last string needs to be null terminated before 0xFF can be used.

headers normally included:
SCPL_VM_TARGET_VERSION
SCPL_VM_MIN_VERSION