#
#  Ace opcode reference
#
#  The following is an assembly language which maps to Ace VM opcodes.
#
#  Instruction names are usually preceded by one of several letters:
#
#  r	reference (stored in one slot) or array
#  b	byte (8-bit) or boolean (1-bit) (stored in an int)
#  c	char (Unicode char, stored in an int)
#  d	double (64-bit floating point number, stored in two 32-bit slots)
#  f	float (32-bit floating point number)
#  i	int (32-bit)
#  l	long (64-bit, stored in two 32-bit slots)
#  s	short (stored in an int)
#
#  Descriptions use the following letters:
#
#  a	The top slot of the stack. May be an int, float or reference.
#  b	The second stack slot. May be an int, float or reference.
#  c	The third stack slot. May be an int, float or reference.
#  d	The fourth stack slot. May be an int, float or reference.
#  ab	The long or double on top of the stack, made up of slots a and b.
#  cd	The long or double on top of the stack, made up of slots c and d.
#
#  Instructions mostly take no arguments. In these cases the information
#  is on the stack, or in local variables implied by the instruction name.
#
#  Some instructions take arguments. If the argument is a type:
#
#  Z	boolean	4
#  C	char	5
#  F	float	6
#  D	double	7
#  B	byte	8
#  S	short	9
#  I	int	10
#  J	long	11
#
#  If the argument is a desc, it can be any of the follow concatenated:
#
#  type		a type letter (see above)
#  [desc	an array of things
#  Lclass;	a complete class name (note the letter L and the semicolon)
#  (desc)V	a method which returns void
#  (desc)desc	a method which accepts parameters and returns one parameter
#
#  For instance:
#
#  invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
#  getstatic java/lang/Math/PI D
#  invokeinterface MyInterface/mymethod (JJ[Ljava/lang/String;)D 6
#  multinewarray [[I 2
#

# Hex	Name		Arguments		Description

00	nop					do nothing

# Loading constants

01	r_const_null				push null reference
10	bi_push		n			push int (-128...127)
11	si_push		n			push short int (-32,768...32767)
12	ldc		x			push x (a constant int, float or String in first 256 constants in pool)
13	ldc_w		x			push x (a constant int, float or String)
14	ldc2_w		x			push x (a constant double or long)

# Loading variable

15	i_load		n			push local int variable n
18	d_load		n			push local double variable n
19	r_load		n			push local reference variable n
2E	ia_load					push int array element a from array b
31	da_load					push double array element a from array b
32	ra_load					push reference array element a from array b

# Storing variables

36	i_store		n			store a in local int variable n
39	d_store		n			store ab in local double variable n
3A	r_store		n			store a in local reference variable n
4F	ia_store				store int a in array element b of array c
52	da_store				store double ab in array element c of array d
53	ra_store				store reference a in array element b of array c

# Stack manipulation

57	pop					remove a
59	dup					duplicate a
5F	swap					swap a and b

# Arithmetic

60	i_add					add int (a+b)
63	d_add					add double (ab+cd)
64	i_sub					subtract int (a-b)
67	d_sub					subtract double (ab-cd)
68	i_mul					multiply int (a*b)
6B	d_mul					multply double (ab*cd)
6C	i_div					divide int (a/b)
6F	d_div					divide double (ab/cd)
70	i_rem					remainder int (a%b)
73	d_rem					remainder double (ab%cd)
74	i_neg					negate int (-a)
77	d_neg					negate double (-ab)
78	i_shl					shift int left (a << b)
7A	i_shr					shift int right (a >> b)
7C	i_ushr					unsigned shift int right (a >>> b)
7E	i_and					bitwise int and (a & b)
80	i_or					bitwise int or (a | b)
82	i_xor					bitwise int xor (a ^ b)
84	i_inc		n increment		increment local variable n

# Conversion

87	i_to_d					convert int a to double
8E	d_to_i					convert double ab to int

# Comparison

94	lcmp		
95	fcmpl					compare float with long
96	fcmpg					compare float
97	dcmpl					compare double with long
98	dcmpg					compare double

# Control

99	if_eq		label			branch if int a == 0
9A	if_ne		label			branch if int a != 0
9B	if_lt		label			branch if int a < 0
9C	if_ge		label			branch if int a >= 0
9D	if_gt		label			branch if int a > 0
9E	if_le		label			branch if int a <= 0

9F	if_i_cmpeq	label			branch if int a == b
A0	if_i_cmpne	label			branch if int a != b
A1	if_i_cmplt	label			branch if int a < b
A2	if_i_cmpge	label			branch if int a >= b
A3	if_i_cmpgt	label			branch if int a > b
A4	if_i_cmple	label			branch if int a <= b
A5	if_r_cmpeq	label			branch if reference a == b
A6	if_r_cmpne	label			branch if reference a != b

A7	goto		label			branch always to label
A8	jsr		label			branch to label; push return location
A9	ret		n			branch to location in variable n
AC	i_return				return int from method
AF	d_return				return double from method
B0	r_return				return reference from method
B1	return					return from method

# Access

B4	getfield	class/field desc	push object field
B5	putfield	class/field desc	store a in object field

B6	invokevirtual	class/method desc	invoke method virtually

# Objects

BB	new		class			create new object of class
BC	newarray	type			create array of type, length a
BD	a_newarray	class			create array of class, length a
BE	arraylength				push length of array
BF	throw					throw exception a
C0	checktype	class			throw exception if a is not an instance of class
C1	instanceof	class			push 1 if a is class, 0 otherwise

# Extras

C5	multinewarray	class n			create multidimensional array with first n dimensions initialized to lengths a, b, c...