jsrt/docs/OPCODES.md

quickjs-ng opcodes

Generated from third_party/quickjs-ng (v0.16.1). Read this beside a listing.

# is the opcode byte. Size counts that byte and its operands together, so it is how far the next instruction is. Stack is pop → push, excluding call arguments, which the operand counts instead. Format names the operand encoding, described in the next table.

Two things to know about the numbering. Short opcodes such as get_loc2 fold an operand into the opcode byte, which is why several names can mean the same operation at different indexes. And short opcodes share numbers with the compiler's temporary opcodes, which never reach a file, so a decoder has to shift the high range past them.

Operand formats

Format	Bytes after the opcode
none	No operand.
none_int	No operand; the integer is folded into the opcode, as in push_3.
none_loc	No operand; the local index is folded into the opcode, as in get_loc2.
none_arg	No operand; the argument index is folded into the opcode.
none_var_ref	No operand; the closure variable index is folded into the opcode.
u8	One unsigned byte.
i8	One signed byte.
loc8	One byte, a local index.
const8	One byte, a constant pool index.
label8	One signed byte, a jump offset from its own position.
u16	Two bytes, unsigned.
i16	Two bytes, signed.
label16	Two signed bytes, a jump offset from its own position.
npop	Two bytes, an argument count. The arguments are on the stack and are not counted in the stack effect.
npopx	No operand; the argument count is folded into the opcode, as in call2.
npop_u16	Two bytes of argument count, then two more bytes.
loc	Two bytes, a local index.
arg	Two bytes, an argument index.
var_ref	Two bytes, a closure variable index.
u32	Four bytes, unsigned.
u32x2	Two four-byte values.
i32	Four bytes, signed.
const	Four bytes, a constant pool index.
label	Four signed bytes, a jump offset from its own position.
atom	Four bytes, an atom reference. Not a raw atom number: it is an index in the file's atom space.
atom_u8	An atom reference then one byte.
atom_u16	An atom reference then two bytes.
atom_label_u8	An atom reference, a four-byte jump offset, then one byte.
atom_label_u16	An atom reference, a four-byte jump offset, then two bytes.
label_u16	A four-byte jump offset then two bytes.

Common opcodes

Function prologue

Opcode	#	Size	Stack	Format	Meaning
push_this	8	1	0 → 1	none	Push the this binding. Only emitted at the start of a function.
special_object	12	2	0 → 1	u8	Push one of the objects a prologue may need, selected by the operand: the arguments object, a mapped arguments object, this.__proto__, new.target, or the home object.
rest	13	3	0 → 1	u16	Build the rest parameter array from the arguments at or after the given index.
fclosure	3	5	0 → 1	const	Take the function template at the given constant pool index and make a closure of it, capturing the current frame's variables.
fclosure8	197	2	0 → 1	const8	fclosure with a one-byte pool index.
init_ctor	44	1	0 → 1	none	Initialise a derived constructor's this slot.

Constants

Opcode	#	Size	Stack	Format	Meaning
push_i32	1	5	0 → 1	i32	Push a 32-bit signed integer given inline.
push_i8	194	2	0 → 1	i8	Push a small signed integer, one byte inline.
push_i16	195	3	0 → 1	i16	Push a signed integer, two bytes inline.
push_const	2	5	0 → 1	const	Push the constant pool entry at the given index. The pool holds nested functions, template objects, and any literal too large to inline.
push_const8	196	2	0 → 1	const8	push_const with a one-byte pool index.
push_atom_value	4	5	0 → 1	atom	Push an interned string, named by an atom rather than stored inline.
push_empty_string	198	1	0 → 1	none	Push "".
push_bigint_i32	177	5	0 → 1	i32	Push a BigInt small enough to fit in 32 bits.
undefined	6	1	0 → 1	none	Push undefined.
null	7	1	0 → 1	none	Push null.
push_true	10	1	0 → 1	none	Push true.
push_false	9	1	0 → 1	none	Push false.
push_minus1	185	1	0 → 1	none_int	Push the integer -1. One of the folded push opcodes, where the value is part of the opcode.
push_0	186	1	0 → 1	none_int	Push the integer 0. push_0 through push_7 fold the value into the opcode byte.
object	11	1	0 → 1	none	Push a new empty object, as {} does.
regexp	52	1	2 → 1	none	Pop a pattern and its compiled libregexp bytecode, push a new RegExp object.

Locals and arguments

Opcode	#	Size	Stack	Format	Meaning
get_loc	87	3	0 → 1	loc	Push local variable N.
put_loc	88	3	1 → 0	loc	Pop and store into local variable N.
set_loc	89	3	1 → 1	loc	Store into local variable N, leaving the value on the stack. This is what an assignment used as an expression compiles to.
get_loc8	199	2	0 → 1	loc8	get_loc with a one-byte index.
get_loc0	203	1	0 → 1	none_loc	Push local 0. get_loc0 through get_loc3 fold the index into the opcode.
get_loc0_loc1	202	1	0 → 2	none_loc	Push local 0 then local 1, in one instruction.
get_arg	90	3	0 → 1	arg	Push argument N.
put_arg	91	3	1 → 0	arg	Pop and store into argument N.
set_arg	92	3	1 → 1	arg	Store into argument N, leaving the value on the stack.
get_arg0	215	1	0 → 1	none_arg	Push argument 0. get_arg0 through get_arg3 fold the index into the opcode.
get_var_ref	93	3	0 → 1	var_ref	Push closure variable N, that is, a variable captured from an enclosing function.
put_var_ref	94	3	1 → 0	var_ref	Pop and store into closure variable N.
set_var_ref	95	3	1 → 1	var_ref	Store into closure variable N, leaving the value on the stack.
get_var_ref0	227	1	0 → 1	none_var_ref	Push closure variable 0. Indexes 0 to 3 are folded into the opcode.
set_loc_uninitialized	96	3	0 → 0	loc	Mark a local as being in its temporal dead zone. Reading it before initialisation must throw, and this is what sets that state.
get_loc_check	97	3	0 → 1	loc	Push a let or const local, throwing a ReferenceError if it is still in its temporal dead zone.
put_loc_check	98	3	1 → 0	loc	Store into a let local, throwing if it is still in its temporal dead zone.
put_loc_check_init	99	3	1 → 0	loc	Perform the initialising store to a let or const local, which is what leaves the dead zone.
get_var_ref_check	100	3	0 → 1	var_ref	Push a captured let or const, throwing if it is still in its temporal dead zone.
put_var_ref_check	101	3	1 → 0	var_ref	Store into a captured let, throwing if it is still in its temporal dead zone.
put_var_ref_check_init	102	3	1 → 0	var_ref	Perform the initialising store to a captured let or const, which is what leaves the dead zone.
close_loc	103	3	0 → 0	loc	Close over a local, so that a closure keeps it alive after the frame goes away.
inc_loc	146	2	0 → 0	loc8	Increment a local in place, without moving it through the stack.
dec_loc	145	2	0 → 0	loc8	Decrement a local in place.
add_loc	147	2	1 → 0	loc8	Add the top of the stack into a local in place.

Variables by name

Opcode	#	Size	Stack	Format	Meaning
get_var	56	5	0 → 1	atom	Push a variable looked up by name at run time, throwing a ReferenceError if it does not exist.
get_var_undef	55	5	0 → 1	atom	Like get_var, but push undefined instead of throwing when the variable does not exist. This is what typeof x on an unknown name uses.
put_var	57	5	1 → 0	atom	Store into a variable looked up by name.
put_var_init	58	5	1 → 0	atom	Perform the initialising store to a global lexical variable.
define_var	61	6	0 → 0	atom_u8	Define a var or function binding on the global object.
check_define_var	62	6	0 → 0	atom_u8	Check that defining this global name is allowed before define_var does it.
define_func	63	6	1 → 0	atom_u8	Define a global function binding from the closure on the stack.
delete_var	152	5	0 → 1	atom	delete applied to a bare name.

The with statement

Opcode	#	Size	Stack	Format	Meaning
with_get_var	115	10	1 → 0	atom_label_u8	Read the name from the with object, or jump to the label if the object does not have it.
with_put_var	116	10	2 → 1	atom_label_u8	Store into the name on the with object, or jump to the label if the object does not have it.
with_delete_var	117	10	1 → 0	atom_label_u8	delete the name on the with object, or jump to the label if the object does not have it.
with_make_ref	118	10	1 → 0	atom_label_u8	Push the object and the property name as a reference pair, for an assignment target inside with.
with_get_ref	119	10	1 → 0	atom_label_u8	Push the object and the named method together, so a call inside with gets its receiver.
with_get_ref_undef	120	10	1 → 0	atom_label_u8	with_get_ref, but push undefined as the receiver instead of the object.

Properties

Opcode	#	Size	Stack	Format	Meaning
get_field	64	5	1 → 1	atom	Pop an object, push obj.name.
get_field2	65	5	1 → 2	atom	Push obj.name but keep the object underneath it, so a following call has its receiver. This is the a.b() shape.
put_field	66	5	2 → 0	atom	Pop a value and an object, store obj.name = value.
get_array_el	70	1	2 → 1	none	Pop a key and an object, push obj[key].
get_array_el2	71	1	2 → 2	none	Push obj[key] while keeping the object, the computed-key form of get_field2.
put_array_el	72	1	3 → 0	none	Pop a value, a key, and an object, store obj[key] = value.
define_field	75	5	2 → 1	atom	Define a named property on an object literal being built.
define_array_el	80	1	3 → 2	none	Define an indexed property on an array literal being built.
append	81	1	3 → 2	none	Append the elements of a spread operand to an array being built, updating its length.
copy_data_properties	82	2	3 → 3	u8	Copy the own enumerable properties of one object to another, for object spread and rest.
delete	151	1	2 → 1	none	delete obj[key], with the key on the stack.
get_length	239	1	1 → 1	none	Push obj.length. Common enough to get its own opcode.
set_name	76	5	1 → 1	atom	Give an anonymous function the name it is being assigned to.
set_name_computed	77	1	2 → 2	none	Give an anonymous function a name computed at run time.
set_proto	78	1	2 → 1	none	Set an object's prototype, from __proto__ in an object literal.
set_home_object	79	1	2 → 2	none	Record a method's home object, which is what super resolves against.
to_object	112	1	1 → 1	none	Coerce the top of the stack to an object.
to_propkey	113	1	1 → 1	none	Coerce the top of the stack to a valid property key.
check_object	111	1	1 → 1	none	Throw if the top of the stack is not an object.

Private fields

Opcode	#	Size	Stack	Format	Meaning
private_symbol	5	5	0 → 1	atom	Push the unique symbol that backs a #name private field.
get_private_field	67	1	2 → 1	none	Read a #name private field, throwing if the object does not carry it.
put_private_field	68	1	3 → 0	none	Write a #name private field.
define_private_field	69	1	3 → 1	none	Install a #name private field on a new instance.
private_in	176	1	2 → 1	none	The #name in obj test, which reports whether the object carries the field.
check_brand	45	1	2 → 2	none	Check that the receiver really is an instance of the class that owns this private method.
add_brand	46	1	2 → 0	none	Mark a new instance as belonging to a class that has private methods.

Classes

Opcode	#	Size	Stack	Format	Meaning
define_class	85	6	2 → 2	atom_u8	Build a class: pop the parent and the constructor, push the constructor and its prototype.
define_class_computed	86	6	3 → 3	atom_u8	define_class for a class whose name is computed at run time.
define_method	83	6	2 → 1	atom_u8	Define a method on a prototype or object literal.
define_method_computed	84	2	3 → 1	u8	define_method with a key computed at run time.
get_super	53	1	1 → 1	none	Push the prototype of the home object, which is what super refers to.
get_super_value	73	1	3 → 1	none	Read super.name, which needs the receiver as well as the home object.
put_super_value	74	1	4 → 0	none	Write super.name.
check_ctor	43	1	0 → 0	none	Throw if a class constructor was called without new.
check_ctor_return	42	1	1 → 2	none	Apply the rule that a constructor returning a non-object yields this instead.

Calls

Opcode	#	Size	Stack	Format	Meaning
call	34	3	1 → 1	npop	Call a function with N arguments. The argument count is the operand, and the arguments are not counted in the stack effect.
call0	244	1	1 → 1	npopx	Call with no arguments. call0 through call3 fold the count into the opcode.
call_method	36	3	2 → 1	npop	Call a method, which takes a receiver as well as the function.
call_constructor	33	3	2 → 1	npop	Call with new, taking the function and new.target.
tail_call	35	3	1 → 0	npop	A call in tail position, which reuses the frame instead of growing the stack.
tail_call_method	37	3	2 → 0	npop	A method call in tail position.
apply	39	3	3 → 1	u16	Call with an array of arguments, as Function.prototype.apply does.
eval	50	5	1 → 1	npop_u16	A direct eval call, which can see the enclosing scope.
apply_eval	51	3	2 → 1	u16	A direct eval call whose arguments come from an array.
array_from	38	3	0 → 1	npop	Build an array from N values on the stack.
return	40	1	1 → 0	none	Return the top of the stack.
return_undef	41	1	0 → 0	none	Return undefined, which is what a function ending without return does.
return_async	47	1	1 → 0	none	Return from an async function, resolving its promise.

Control flow

Opcode	#	Size	Stack	Format	Meaning
goto	106	5	0 → 0	label	Jump. The operand is a signed offset from its own position, which the listing shows resolved to a label.
goto8	242	2	0 → 0	label8	goto with a one-byte offset.
goto16	243	3	0 → 0	label16	goto with a two-byte offset.
if_false	104	5	1 → 0	label	Pop a value and jump if it is falsy.
if_true	105	5	1 → 0	label	Pop a value and jump if it is truthy.
if_false8	240	2	1 → 0	label8	if_false with a one-byte offset.
if_true8	241	2	1 → 0	label8	if_true with a one-byte offset.
catch	107	5	0 → 1	label	Push a catch context pointing at the handler, arming the try block that follows.
gosub	108	5	0 → 0	label	Enter a finally block, remembering where to resume.
ret	109	1	1 → 0	none	Leave a finally block and resume where gosub came from.
nip_catch	110	1	2 → 1	none	Drop a catch context from under the value on top, leaving the try block.
throw	48	1	1 → 0	none	Throw the value on top of the stack.
throw_error	49	6	0 → 0	atom_u8	Throw a built-in error, named by the operand. Used for the errors the compiler knows about in advance.
nop	184	1	0 → 0	none	Do nothing. Left behind where an optimisation removed an instruction.
invalid	0	1	0 → 0	none	Opcode 0, which upstream marks never emitted. Seeing it in a listing means the decode lost its place, not that the compiler produced it.

Iteration

Opcode	#	Size	Stack	Format	Meaning
for_in_start	125	1	1 → 1	none	Begin a for...in loop over the object on the stack.
for_in_next	128	1	1 → 3	none	Take the next key of a for...in loop, pushing the key and whether the loop is done.
for_of_start	126	1	1 → 3	none	Begin a for...of loop by fetching the iterator of the object on the stack.
for_of_next	129	2	3 → 5	u8	Take the next value of a for...of loop.
for_await_of_start	127	1	1 → 3	none	Begin a for await...of loop, fetching the async iterator.
iterator_next	132	1	4 → 4	none	Call the iterator's next method.
iterator_call	133	2	4 → 5	u8	Call an optional iterator method such as return or throw, if the iterator has it.
iterator_get_value_done	130	1	1 → 2	none	Split an iterator result object into its value and done fields.
iterator_close	131	1	3 → 0	none	Close an iterator early, which is what a break out of for...of must do.

Generators and async

Opcode	#	Size	Stack	Format	Meaning
initial_yield	134	1	0 → 0	none	Suspend immediately on entry, so a generator body does not run until the first next call.
yield	135	1	1 → 2	none	Suspend and hand a value to the caller.
yield_star	136	1	1 → 2	none	yield*, delegating to another iterator.
async_yield_star	137	1	1 → 2	none	yield* inside an async generator.
await	138	1	1 → 1	none	Suspend until a promise settles.
import	54	1	2 → 1	none	A dynamic import(), which yields a promise.

Resource management

Opcode	#	Size	Stack	Format	Meaning
using_check	183	2	1 → 2	u8	Check that a using declaration's value has the disposal method it needs.
using_dispose_init	178	1	0 → 1	none	Start the disposal list for a scope holding using declarations.
using_dispose	179	3	1 → 1	loc	Register a value for disposal when the scope ends.
using_dispose_async	180	3	0 → 1	loc	Register a value for await using disposal.
using_dispose_merge	181	1	2 → 1	none	Merge an inner scope's disposal list into the enclosing one.
using_dispose_end	182	1	1 → 0	none	Run the disposal list as the scope ends.

Operators

Opcode	#	Size	Stack	Format	Meaning
add	156	1	2 → 1	none	a + b, which is either numeric addition or string concatenation.
sub	157	1	2 → 1	none	a - b.
mul	153	1	2 → 1	none	a * b.
div	154	1	2 → 1	none	a / b.
mod	155	1	2 → 1	none	a % b.
pow	164	1	2 → 1	none	a ** b.
neg	139	1	1 → 1	none	Unary -a.
plus	140	1	1 → 1	none	Unary +a, which coerces to a number.
inc	142	1	1 → 1	none	Add one, for the prefix ++a.
dec	141	1	1 → 1	none	Subtract one, for the prefix --a.
post_inc	144	1	1 → 2	none	a++: push the old value as well, since that is what the expression evaluates to.
post_dec	143	1	1 → 2	none	a--, keeping the old value.
not	148	1	1 → 1	none	Bitwise ~a.
lnot	149	1	1 → 1	none	Logical !a.
typeof	150	1	1 → 1	none	typeof a.
shl	158	1	2 → 1	none	a << b.
sar	159	1	2 → 1	none	a >> b, the sign-propagating shift.
shr	160	1	2 → 1	none	a >>> b, the zero-filling shift.
and	161	1	2 → 1	none	Bitwise a & b.
or	163	1	2 → 1	none	Bitwise a | b.
xor	162	1	2 → 1	none	Bitwise a ^ b.
lt	165	1	2 → 1	none	a < b.
lte	166	1	2 → 1	none	a <= b.
gt	167	1	2 → 1	none	a > b.
gte	168	1	2 → 1	none	a >= b.
eq	171	1	2 → 1	none	a == b, with coercion.
neq	172	1	2 → 1	none	a != b.
strict_eq	173	1	2 → 1	none	a === b.
strict_neq	174	1	2 → 1	none	a !== b.
instanceof	169	1	2 → 1	none	a instanceof b.
in	170	1	2 → 1	none	a in b.
is_undefined	248	1	1 → 1	none	Test for undefined without a comparison.
is_null	249	1	1 → 1	none	Test for null without a comparison.
is_undefined_or_null	175	1	1 → 1	none	The == null test, which both ?. and ?? need.
typeof_is_undefined	250	1	1 → 1	none	The whole of typeof a === "undefined" in one instruction.
typeof_is_function	251	1	1 → 1	none	The whole of typeof a === "function" in one instruction.

Stack

Opcode	#	Size	Stack	Format	Meaning
drop	14	1	1 → 0	none	Discard the top of the stack.
dup	17	1	1 → 2	none	Duplicate the top of the stack.
dup1	18	1	2 → 3	none	Duplicate the second item, leaving a b as a a b.
dup2	19	1	2 → 4	none	Duplicate the top pair.
dup3	20	1	3 → 6	none	Duplicate the top three.
nip	15	1	2 → 1	none	Drop the second item, leaving a b as b.
nip1	16	1	3 → 2	none	Drop the third item.
swap	27	1	2 → 2	none	Exchange the top two.
swap2	28	1	4 → 4	none	Exchange the top two pairs.
insert2	21	1	2 → 3	none	Copy the top item below the one beneath it, so a receiver survives a call.
insert3	22	1	3 → 4	none	Copy the top item down past two others.
insert4	23	1	4 → 5	none	Copy the top item down past three others.
perm3	24	1	3 → 3	none	Rotate the top three so the deepest comes second.
perm4	25	1	4 → 4	none	Rotate the top four.
perm5	26	1	5 → 5	none	Rotate the top five.
rot3l	29	1	3 → 3	none	Rotate the top three left.
rot3r	30	1	3 → 3	none	Rotate the top three right.
rot4l	31	1	4 → 4	none	Rotate the top four left.
rot5l	32	1	5 → 5	none	Rotate the top five left.

References

Opcode	#	Size	Stack	Format	Meaning
make_loc_ref	121	7	0 → 2	atom_u16	Build a reference to a local, so it can be written through later.
make_arg_ref	122	7	0 → 2	atom_u16	Build a reference to an argument.
make_var_ref	124	5	0 → 2	atom	Build a reference to a variable named by an atom.
make_var_ref_ref	123	7	0 → 2	atom_u16	Build a reference to a captured variable.
get_ref_value	59	1	2 → 3	none	Read through a reference.
put_ref_value	60	1	3 → 0	none	Write through a reference.

All opcodes

Every opcode quickjs-ng defines, in numeric order. The comment column is upstream's own, where it has one.

#	Name	Size	Pop	Push	Format	Notes
0	invalid	1	0	0	none	explained above
1	push_i32	5	0	1	i32	explained above
2	push_const	5	0	1	const	explained above
3	fclosure	5	0	1	const	explained above
4	push_atom_value	5	0	1	atom	explained above
5	private_symbol	5	0	1	atom	explained above
6	undefined	1	0	1	none	explained above
7	null	1	0	1	none	explained above
8	push_this	1	0	1	none	explained above
9	push_false	1	0	1	none	explained above
10	push_true	1	0	1	none	explained above
11	object	1	0	1	none	explained above
12	special_object	2	0	1	u8	explained above
13	rest	3	0	1	u16	explained above
14	drop	1	1	0	none	explained above
15	nip	1	2	1	none	explained above
16	nip1	1	3	2	none	explained above
17	dup	1	1	2	none	explained above
18	dup1	1	2	3	none	explained above
19	dup2	1	2	4	none	explained above
20	dup3	1	3	6	none	explained above
21	insert2	1	2	3	none	explained above
22	insert3	1	3	4	none	explained above
23	insert4	1	4	5	none	explained above
24	perm3	1	3	3	none	explained above
25	perm4	1	4	4	none	explained above
26	perm5	1	5	5	none	explained above
27	swap	1	2	2	none	explained above
28	swap2	1	4	4	none	explained above
29	rot3l	1	3	3	none	explained above
30	rot3r	1	3	3	none	explained above
31	rot4l	1	4	4	none	explained above
32	rot5l	1	5	5	none	explained above
33	call_constructor	3	2	1	npop	explained above
34	call	3	1	1	npop	explained above
35	tail_call	3	1	0	npop	explained above
36	call_method	3	2	1	npop	explained above
37	tail_call_method	3	2	0	npop	explained above
38	array_from	3	0	1	npop	explained above
39	apply	3	3	1	u16	explained above
40	return	1	1	0	none	explained above
41	return_undef	1	0	0	none	explained above
42	check_ctor_return	1	1	2	none	explained above
43	check_ctor	1	0	0	none	explained above
44	init_ctor	1	0	1	none	explained above
45	check_brand	1	2	2	none	explained above
46	add_brand	1	2	0	none	explained above
47	return_async	1	1	0	none	explained above
48	throw	1	1	0	none	explained above
49	throw_error	6	0	0	atom_u8	explained above
50	eval	5	1	1	npop_u16	explained above
51	apply_eval	3	2	1	u16	explained above
52	regexp	1	2	1	none	explained above
53	get_super	1	1	1	none	explained above
54	import	1	2	1	none	explained above
55	get_var_undef	5	0	1	atom	explained above
56	get_var	5	0	1	atom	explained above
57	put_var	5	1	0	atom	explained above
58	put_var_init	5	1	0	atom	explained above
59	get_ref_value	1	2	3	none	explained above
60	put_ref_value	1	3	0	none	explained above
61	define_var	6	0	0	atom_u8	explained above
62	check_define_var	6	0	0	atom_u8	explained above
63	define_func	6	1	0	atom_u8	explained above
64	get_field	5	1	1	atom	explained above
65	get_field2	5	1	2	atom	explained above
66	put_field	5	2	0	atom	explained above
67	get_private_field	1	2	1	none	explained above
68	put_private_field	1	3	0	none	explained above
69	define_private_field	1	3	1	none	explained above
70	get_array_el	1	2	1	none	explained above
71	get_array_el2	1	2	2	none	explained above
72	put_array_el	1	3	0	none	explained above
73	get_super_value	1	3	1	none	explained above
74	put_super_value	1	4	0	none	explained above
75	define_field	5	2	1	atom	explained above
76	set_name	5	1	1	atom	explained above
77	set_name_computed	1	2	2	none	explained above
78	set_proto	1	2	1	none	explained above
79	set_home_object	1	2	2	none	explained above
80	define_array_el	1	3	2	none	explained above
81	append	1	3	2	none	explained above
82	copy_data_properties	2	3	3	u8	explained above
83	define_method	6	2	1	atom_u8	explained above
84	define_method_computed	2	3	1	u8	explained above
85	define_class	6	2	2	atom_u8	explained above
86	define_class_computed	6	3	3	atom_u8	explained above
87	get_loc	3	0	1	loc	explained above
88	put_loc	3	1	0	loc	explained above
89	set_loc	3	1	1	loc	explained above
90	get_arg	3	0	1	arg	explained above
91	put_arg	3	1	0	arg	explained above
92	set_arg	3	1	1	arg	explained above
93	get_var_ref	3	0	1	var_ref	explained above
94	put_var_ref	3	1	0	var_ref	explained above
95	set_var_ref	3	1	1	var_ref	explained above
96	set_loc_uninitialized	3	0	0	loc	explained above
97	get_loc_check	3	0	1	loc	explained above
98	put_loc_check	3	1	0	loc	explained above
99	put_loc_check_init	3	1	0	loc	explained above
100	get_var_ref_check	3	0	1	var_ref	explained above
101	put_var_ref_check	3	1	0	var_ref	explained above
102	put_var_ref_check_init	3	1	0	var_ref	explained above
103	close_loc	3	0	0	loc	explained above
104	if_false	5	1	0	label	explained above
105	if_true	5	1	0	label	explained above
106	goto	5	0	0	label	explained above
107	catch	5	0	1	label	explained above
108	gosub	5	0	0	label	explained above
109	ret	1	1	0	none	explained above
110	nip_catch	1	2	1	none	explained above
111	check_object	1	1	1	none	explained above
112	to_object	1	1	1	none	explained above
113	to_propkey	1	1	1	none	explained above
114	to_propkey2	1	2	2	none
115	with_get_var	10	1	0	atom_label_u8	explained above
116	with_put_var	10	2	1	atom_label_u8	explained above
117	with_delete_var	10	1	0	atom_label_u8	explained above
118	with_make_ref	10	1	0	atom_label_u8	explained above
119	with_get_ref	10	1	0	atom_label_u8	explained above
120	with_get_ref_undef	10	1	0	atom_label_u8	explained above
121	make_loc_ref	7	0	2	atom_u16	explained above
122	make_arg_ref	7	0	2	atom_u16	explained above
123	make_var_ref_ref	7	0	2	atom_u16	explained above
124	make_var_ref	5	0	2	atom	explained above
125	for_in_start	1	1	1	none	explained above
126	for_of_start	1	1	3	none	explained above
127	for_await_of_start	1	1	3	none	explained above
128	for_in_next	1	1	3	none	explained above
129	for_of_next	2	3	5	u8	explained above
130	iterator_get_value_done	1	1	2	none	explained above
131	iterator_close	1	3	0	none	explained above
132	iterator_next	1	4	4	none	explained above
133	iterator_call	2	4	5	u8	explained above
134	initial_yield	1	0	0	none	explained above
135	yield	1	1	2	none	explained above
136	yield_star	1	1	2	none	explained above
137	async_yield_star	1	1	2	none	explained above
138	await	1	1	1	none	explained above
139	neg	1	1	1	none	explained above
140	plus	1	1	1	none	explained above
141	dec	1	1	1	none	explained above
142	inc	1	1	1	none	explained above
143	post_dec	1	1	2	none	explained above
144	post_inc	1	1	2	none	explained above
145	dec_loc	2	0	0	loc8	explained above
146	inc_loc	2	0	0	loc8	explained above
147	add_loc	2	1	0	loc8	explained above
148	not	1	1	1	none	explained above
149	lnot	1	1	1	none	explained above
150	typeof	1	1	1	none	explained above
151	delete	1	2	1	none	explained above
152	delete_var	5	0	1	atom	explained above
153	mul	1	2	1	none	explained above
154	div	1	2	1	none	explained above
155	mod	1	2	1	none	explained above
156	add	1	2	1	none	explained above
157	sub	1	2	1	none	explained above
158	shl	1	2	1	none	explained above
159	sar	1	2	1	none	explained above
160	shr	1	2	1	none	explained above
161	and	1	2	1	none	explained above
162	xor	1	2	1	none	explained above
163	or	1	2	1	none	explained above
164	pow	1	2	1	none	explained above
165	lt	1	2	1	none	explained above
166	lte	1	2	1	none	explained above
167	gt	1	2	1	none	explained above
168	gte	1	2	1	none	explained above
169	instanceof	1	2	1	none	explained above
170	in	1	2	1	none	explained above
171	eq	1	2	1	none	explained above
172	neq	1	2	1	none	explained above
173	strict_eq	1	2	1	none	explained above
174	strict_neq	1	2	1	none	explained above
175	is_undefined_or_null	1	1	1	none	explained above
176	private_in	1	2	1	none	explained above
177	push_bigint_i32	5	0	1	i32	explained above
178	using_dispose_init	1	0	1	none	explained above
179	using_dispose	3	1	1	loc	explained above
180	using_dispose_async	3	0	1	loc	explained above
181	using_dispose_merge	1	2	1	none	explained above
182	using_dispose_end	1	1	0	none	explained above
183	using_check	2	1	2	u8	explained above
184	nop	1	0	0	none	explained above
185	push_minus1	1	0	1	none_int	explained above
186	push_0	1	0	1	none_int	explained above
187	push_1	1	0	1	none_int
188	push_2	1	0	1	none_int
189	push_3	1	0	1	none_int
190	push_4	1	0	1	none_int
191	push_5	1	0	1	none_int
192	push_6	1	0	1	none_int
193	push_7	1	0	1	none_int
194	push_i8	2	0	1	i8	explained above
195	push_i16	3	0	1	i16	explained above
196	push_const8	2	0	1	const8	explained above
197	fclosure8	2	0	1	const8	explained above
198	push_empty_string	1	0	1	none	explained above
199	get_loc8	2	0	1	loc8	explained above
200	put_loc8	2	1	0	loc8
201	set_loc8	2	1	1	loc8
202	get_loc0_loc1	1	0	2	none_loc	explained above
203	get_loc0	1	0	1	none_loc	explained above
204	get_loc1	1	0	1	none_loc
205	get_loc2	1	0	1	none_loc
206	get_loc3	1	0	1	none_loc
207	put_loc0	1	1	0	none_loc
208	put_loc1	1	1	0	none_loc
209	put_loc2	1	1	0	none_loc
210	put_loc3	1	1	0	none_loc
211	set_loc0	1	1	1	none_loc
212	set_loc1	1	1	1	none_loc
213	set_loc2	1	1	1	none_loc
214	set_loc3	1	1	1	none_loc
215	get_arg0	1	0	1	none_arg	explained above
216	get_arg1	1	0	1	none_arg
217	get_arg2	1	0	1	none_arg
218	get_arg3	1	0	1	none_arg
219	put_arg0	1	1	0	none_arg
220	put_arg1	1	1	0	none_arg
221	put_arg2	1	1	0	none_arg
222	put_arg3	1	1	0	none_arg
223	set_arg0	1	1	1	none_arg
224	set_arg1	1	1	1	none_arg
225	set_arg2	1	1	1	none_arg
226	set_arg3	1	1	1	none_arg
227	get_var_ref0	1	0	1	none_var_ref	explained above
228	get_var_ref1	1	0	1	none_var_ref
229	get_var_ref2	1	0	1	none_var_ref
230	get_var_ref3	1	0	1	none_var_ref
231	put_var_ref0	1	1	0	none_var_ref
232	put_var_ref1	1	1	0	none_var_ref
233	put_var_ref2	1	1	0	none_var_ref
234	put_var_ref3	1	1	0	none_var_ref
235	set_var_ref0	1	1	1	none_var_ref
236	set_var_ref1	1	1	1	none_var_ref
237	set_var_ref2	1	1	1	none_var_ref
238	set_var_ref3	1	1	1	none_var_ref
239	get_length	1	1	1	none	explained above
240	if_false8	2	1	0	label8	explained above
241	if_true8	2	1	0	label8	explained above
242	goto8	2	0	0	label8	explained above
243	goto16	3	0	0	label16	explained above
244	call0	1	1	1	npopx	explained above
245	call1	1	1	1	npopx
246	call2	1	1	1	npopx
247	call3	1	1	1	npopx
248	is_undefined	1	1	1	none	explained above
249	is_null	1	1	1	none	explained above
250	typeof_is_undefined	1	1	1	none	explained above
251	typeof_is_function	1	1	1	none	explained above

Temporary opcodes

These exist only inside the compiler and are removed before anything is written to a file. They are listed because their numbers overlap the short opcodes, starting at OP_TEMP_START = 185, and a decoder must account for the 19 of them.

Name	Size	Format
enter_scope	3	u16
leave_scope	3	u16
label	5	label
scope_get_var_undef	7	atom_u16
scope_get_var	7	atom_u16
scope_put_var	7	atom_u16
scope_delete_var	7	atom_u16
scope_make_ref	11	atom_label_u16
scope_get_ref	7	atom_u16
scope_put_var_init	7	atom_u16
scope_get_private_field	7	atom_u16
scope_get_private_field2	7	atom_u16
scope_put_private_field	7	atom_u16
scope_in_private_field	7	atom_u16
get_field_opt_chain	5	atom
get_array_el_opt_chain	1	none
set_class_name	5	u32
dispose_scope	3	u16
source_loc	9	u32x2

---

252 opcodes, 206 explained above.