The compiled form of LSL scripts - a mostly stack-based language with a reference-counted heap and a very odd function calling convention in which the caller allocates storage for the callee's local variables. All the gory details can be found at http://www.libsecondlife.org/wiki/LSO, including some opcodes that are implemented in the interpreter but never outputted by the compiler (such as the handy DUP family of instructions for Forth-style programming, and PUSHIP/POPIP for implementing custom function calls/function pointers, jumptable-based switch statements and the like).
It's actually a reasonably powerful instruction set in some ways, but the compiler doesn't make use of it very well. Of course, with the planned switch to Mono, it's probably really not sensible to do anything with it. Besides, rumor has it that script compilation will move server-side in the near future.
Bytecodes
| Argument Types
|
Variable type codes
|
| Type
|
Size
|
|
| dword
|
4
|
|
| short
|
2
|
|
| byte
|
1
|
|
| type
|
1
|
upper 4 bits are type.Left
lower 4 bits are type.Right
|
|
| Value
|
Type
|
Size
|
| 0
|
void
|
?
|
| 1
|
integer
|
4
|
| 2
|
float
|
4
|
| 3
|
string
|
4
|
|
| Value
|
Type
|
Size
|
| 4
|
key
|
4
|
| 5
|
vector
|
12
|
| 6
|
rotation
|
16
|
| 7
|
list
|
4
|
|
By Task
Value Pop
These bytecodes remove values from the stack.
|-
| POP
| 0x01
| Pops a dword from the stack.
|
|-
| POPS
| 0x02
| Pops a dword from the stack and deallocates it from the heap as a string
|
|-
| POPL
| 0x03
| Pops a dword from the stack and deallocates it from the heap as a list
|
|-
| POPV
| 0x04
| Pops 3 dwords from the stack.
|
|-
| POPQ
| 0x05
| Pops 4 dwords from the stack.
|
|-
| POPARG
| 0x06
| Pops arg0 bytes from the stack.
| dword
Operators
| Description
|
arg0 size
|
| CAST
|
0xA0
|
Pop type.Left, convert Left to type.Right and push the result onto the stack.
|
type
|
| NEG
|
0x80
|
Pop type.Right, push result of (-Right) onto the stack.
|
type
|
| ADD
|
0x70
|
Pop type.Right then type.Left, push result of (Left + Right) onto the stack.
|
type
|
| SUB
|
0x71
|
Pop type.Right then type.Left, push result of (Left - Right) onto the stack.
|
type
|
| MUL
|
0x72
|
Pop type.Right then type.Left, push result of (Left * Right) onto the stack.
|
type
|
| DIV
|
0x73
|
Pop type.Right then type.Left, push result of (Left / Right) onto the stack.
|
type
|
| MOD
|
0x74
|
Pop type.Right then type.Left, push result of (Left % Right) onto the stack.
|
type
|
| EQ
|
0x75
|
Pop type.Right then type.Left, push result of (Left == Right) onto the stack.
|
type
|
| NEQ
|
0x76
|
Pop type.Right then type.Left, push result of (Left != Right) onto the stack.
|
type
|
| LEQ
|
0x77
|
Pop type.Right then type.Left, push result of (Left <= Right) onto the stack.
|
type
|
| GEQ
|
0x78
|
Pop type.Right then type.Left, push result of (Left >= Right) onto the stack.
|
type
|
| LESS
|
0x79
|
Pop type.Right then type.Left, push result of (Left < Right) onto the stack.
|
type
|
| GREATER
|
0x7A
|
Pop type.Right then type.Left, push result of (Left > Right) onto the stack.
|
type
|
| BITAND
|
0x7B
|
Pop dword (Right) then dword (Left), push result of (Left & Right) onto the stack.
|
| BITOR
|
0x7C
|
Pop dword (Right) then dword (Left), push result of (Left | Right) onto the stack.
|
| BITXOR
|
0x7D
|
Pop dword (Right) then dword (Left), push result of (Left ^ Right) onto the stack.
|
| BOOLAND
|
0x7E
|
Pop dword (Right) then dword (Left), push result of (Left && Right) onto the stack.
|
| BOOLOR
|
0x7F
|
Pop dword (Right) then dword (Left), push result of (Left || Right) onto the stack.
|
| BITNOT
|
0x81
|
Pop dword (Right), push result of (~Right) onto the stack.
|
| BOOLNOT
|
0x82
|
Pop dword (Right), push result of (!Right) onto the stack.
|
| SHL
|
0xE0
|
Pop dword (Right) then dword (Left), push result of (Left << Right) onto the stack.
|
| SHR
|
0xE1
|
Pop dword (Right) then dword (Left), push result of (Left >> Right) onto the stack.
|
Jumps
| Description
|
arg0 size
|
arg1 size
|
| JUMP
|
0x90
|
Jump to offset arg0 local to this instruction. arg0 is signed.
|
dword
|
| JUMPIF
|
0x91
|
Pop type.Right, if Right is executes to true jump to offset arg1 local to this instruction. arg1 is signed.
|
type
|
dword
|
| JUMPNIF
|
0x92
|
Pop type.Right, if Right is executes to false jump to offset arg1 local to this instruction. arg1 is signed.
|
type
|
dword
|
Duplicate Value
| Description
|
arg0 size
|
| DUP
|
0x20
|
Copy dword from stack and push the copy onto the stack.
|
| DUPS
|
0x21
|
Copy string from stack and push the copy onto the stack.
|
| DUPL
|
0x22
|
Copy list from stack and push the copy onto the stack.
|
| DUPV
|
0x23
|
Copy 3 dwrods from stack and push the copy onto the stack.
|
| DUPQ
|
0x24
|
Copy 4 dwrods from stack and push the copy onto the stack.
|
Return
| Description
|
arg0 size
|
| STATE
|
0x93
|
Change state to arg0 and return (see RETURN)
|
dword
|
| RETURN
|
0x95
|
Revert the Instruction and Stack pointers.
|
Functions
| Description
|
arg0 size
|
| CALL
|
0x94
|
Execute user function arg0.
|
dword
|
| CALLLIB
|
0xD0
|
Execute built-in function arg0
|
byte
|
| CALLLIB_TWO_BYTE
|
0xD1
|
Execute built-in function arg0
|
word
|