Java instruction set

This placeholder page will soon contain a table with all Java bytecode instructions, timings, and the observed behavior for each Java instruction, along with some quirks and unexpected register usage.

This header will be left here until all instructions are manually entered into tables

Instruction set

Here is the Java instruction set as found on Wikipedia, except some instructions translate easily to ARM instructions, and some are always callbacks.

The HW column represents how an instruction is handled by Jazelle:

HW	Description
	Always translate natively to ARM
x	Always executed via callback in r5 table
?	Instruction not yet tested at all, or not tested properly
c	Conditional native execution or callback (see instruction notes)

Please note that the table is still under investigation, so some fields in the HW column might be bad

---

Hex	HW	Official instruction name	Notes
00		NOP
01	?	ACONST_NULL
02		ICONST_M1
03		ICONST_0
04		ICONST_1
05		ICONST_2
06		ICONST_3
07		ICONST_4
08		ICONST_5
09	?	LCONST_0
0A	?	LCONST_1
0B		FCONST_0
0C	?	FCONST_1
0D	?	FCONST_2
0E	?	DCONST_0
0F	?	DCONST_1	TODO: test this instruction
10		BIPUSH
11		SIPUSH
12	x	LDC
13	x	LDC_W
14	x	LDC2_W
15		ILOAD
16		LLOAD
17		FLOAD
18		DLOAD
19		ALOAD
1A		ILOAD_0
1B		ILOAD_1
1C		ILOAD_2
1D		ILOAD_3
1E		LLOAD_0
1F		LLOAD_1
20		LLOAD_2
21		LLOAD_3
22		FLOAD_0
23		FLOAD_1
24		FLOAD_2
25		FLOAD_3
26		DLOAD_0
27		DLOAD_1
28		DLOAD_2
29		DLOAD_3
2A		ALOAD_0
2B		ALOAD_1
2C		ALOAD_2
2D		ALOAD_3
2E	c	IALOAD	Sometimes calls the callback function, sometimes not. TODO: what causes this?
2F	c	LALOAD	* Same as 2E IALOAD *
30	c	FALOAD	* Same as 2E IALOAD *
31	c	DALOAD	* Same as 2E IALOAD *
32	?	AALOAD	* Same as 2E IALOAD *
33	c	BALOAD	* Same as 2E IALOAD *
34	c	CALOAD	* Same as 2E IALOAD *
35	c	SALOAD	* Same as 2E IALOAD *
36		ISTORE
37		LSTORE
38		FSTORE
39		DSTORE
3A		ASTORE
3B		ISTORE_0
3C		ISTORE_1
3D		ISTORE_2
3E		ISTORE_3
3F		LSTORE_0
40		LSTORE_1
41		LSTORE_2
42		LSTORE_3
43		FSTORE_0
44		FSTORE_1
45		FSTORE_2
46		FSTORE_3
47		DSTORE_0
48		DSTORE_1
49		DSTORE_2
4A		DSTORE_3
4B	?	ASTORE_0
4C	?	ASTORE_1
4D	?	ASTORE_2
4E	?	ASTORE_3
4F	?	IASTORE	* Same as 2E IALOAD *
50	?	LASTORE	* Same as 2E IALOAD *
51	?	FASTORE	* Same as 2E IALOAD *
52	?	DASTORE	* Same as 2E IALOAD *
53	?	AASTORE	TODO: do more tests with this instruction
54	?	BASTORE
55	?	CASTORE
56	?	SASTORE
57		POP
58		POP2
59		DUP
5A		DUP_X1
5B		DUP_X2
5C		DUP2
5D		DUP2_X1
5E		DUP2_X2
5F		SWAP
60		IADD
61		LADD
62	?	FADD
63	?	DADD
64		ISUB
65		LSUB
66	?	FSUB
67	?	DSUB
68		IMUL
69		LMUL
6A	?	FMUL
6B	?	DMUL
6C	x	IDIV
6D	x	LDIV
6E	?	FDIV
6F	?	DDIV
70	x	IREM
71	x	LREM
72	?	FREM
73	?	DREM
74		INEG
75		LNEG
76	?	FNEG
77	?	DNEG
78		ISHL
79	?	LSHL
7A		ISHR
7B	?	LSHR
7C	?	IUSHR
7D	?	LUSHR
7E		IAND
7F	?	LAND
80		IOR
81	?	LOR
82		IXOR
83	?	LXOR
84		IINC
85	?	I2L
86	x	I2F
87	x	I2D
88	?	L2I
89	x	L2F
8A	x	L2D
8B	x	F2I
8C	x	F2L
8D	x	F2D
8E	x	D2I
8F	x	D2L
90	x	D2F
91		I2B
92		I2C
93		I2S
94	?	LCMP
95	x	FCMPL
96	x	FCMPG
97	x	DCMPL
98	x	DCMPG
99		IFEQ
9A		IFNE
9B		IFLT
9C		IFGE
9D		IFGT
9E		IFLE
9F		IF_ICMPEQ
A0		IF_ICMPNE
A1		IF_ICMPLT
A2		IF_ICMPGE
A3		IF_ICMPGT
A4		IF_ICMPLE
A5		IF_ACMPEQ
A6		IF_ACMPNE
A7		GOTO
A8	?	JSR
A9	?	RET
AA	?	TABLESWITCH
AB	?	LOOKUPSWITCH
AC	x	IRETURN
AD	x	LRETURN
AE	x	FRETURN
AF	x	DRETURN
B0	x	ARETURN
B1	x	RETURN
B2	?	GETSTATIC
B3	?	PUTSTATIC
B4	?	GETFIELD
B5	?	PUTFIELD
B6	x	INVOKEVIRTUAL
B7	x	INVOKESPECIAL
B8	x	INVOKESTATIC
B9	x	INVOKEINTERFACE
BA	x	INVOKEDYNAMIC
BB	x	NEW
BC	x	NEWARRAY
BD	x	ANEWARRAY
BE	?	ARRAYLENGTH
BF	x	ATHROW
C0	x	CHECKCAST
C1	x	INSTANCEOF
C2	?	MONITORENTER
C3	?	MONITOREXIT
C4	?	WIDE
C5	x	MULTIANEWARRAY
C6	?	IFNULL
C7	?	IFNONNULL
C8	?	GOTO_W
C9	?	JSR_W
CA	?	BREAKPOINT
CB to FE	x	* undefined *
FF		BKPT #0	Executes an ARM BKPT #0 instruction