General design
- The machine model and calling conventions are meant to approximately
imitate common real architectures and C-style calling conventions:
- The machine is register-based, and frames are fixed in size upon creation.
Each frame consists of a particular number of registers (specified by
the method) as well as any adjunct data needed to execute the method,
such as (but not limited to) the program counter and a reference to the
.dex
file that contains the method. - When used for bit values (such as integers and floating point numbers), registers are considered 32 bits wide. Adjacent register pairs are used for 64-bit values. There is no alignment requirement for register pairs.
- When used for object references, registers are considered wide enough to hold exactly one such reference.
- In terms of bitwise representation,
(Object) null == (int) 0
. - The N arguments to a method land in the last N registers
of the method's invocation frame, in order. Wide arguments consume
two registers. Instance methods are passed a
this
reference as their first argument.
- The machine is register-based, and frames are fixed in size upon creation.
Each frame consists of a particular number of registers (specified by
the method) as well as any adjunct data needed to execute the method,
such as (but not limited to) the program counter and a reference to the
- The storage unit in the instruction stream is a 16-bit unsigned quantity. Some bits in some instructions are ignored / must-be-zero.
- Instructions aren't gratuitously limited to a particular type. For example, instructions that move 32-bit register values without interpretation don't have to specify whether they are moving ints or floats.
- There are separately enumerated and indexed constant pools for references to strings, types, fields, and methods.
- Bitwise literal data is represented in-line in the instruction stream.
- Because, in practice, it is uncommon for a method to need more than
16 registers, and because needing more than eight registers is
reasonably common, many instructions are limited to only addressing
the first 16
registers. When reasonably possible, instructions allow references to
up to the first 256 registers. In addition, some instructions have variants
that allow for much larger register counts, including a pair of catch-all
move
instructions that can address registers in the rangev0
–v65535
. In cases where an instruction variant isn't available to address a desired register, it is expected that the register contents get moved from the original register to a low register (before the operation) and/or moved from a low result register to a high register (after the operation). - There are several "pseudo-instructions" that are used to hold
variable-length data payloads, which are referred to by regular
instructions (for example,
fill-array-data
). Such instructions must never be encountered during the normal flow of execution. In addition, the instructions must be located on even-numbered bytecode offsets (that is, 4-byte aligned). In order to meet this requirement, dex generation tools must emit an extranop
instruction as a spacer if such an instruction would otherwise be unaligned. Finally, though not required, it is expected that most tools will choose to emit these instructions at the ends of methods, since otherwise it would likely be the case that additional instructions would be needed to branch around them. - When installed on a running system, some instructions may be altered, changing their format, as an install-time static linking optimization. This is to allow for faster execution once linkage is known. See the associated instruction formats document for the suggested variants. The word "suggested" is used advisedly; it is not mandatory to implement these.
- Human-syntax and mnemonics:
- Dest-then-source ordering for arguments.
- Some opcodes have a disambiguating name suffix to indicate the type(s)
they operate on:
- Type-general 32-bit opcodes are unmarked.
- Type-general 64-bit opcodes are suffixed with
-wide
. - Type-specific opcodes are suffixed with their type (or a
straightforward abbreviation), one of:
-boolean
-byte
-char
-short
-int
-long
-float
-double
-object
-string
-class
-void
.
- Some opcodes have a disambiguating suffix to distinguish
otherwise-identical operations that have different instruction layouts
or options. These suffixes are separated from the main names with a slash
("
/
") and mainly exist at all to make there be a one-to-one mapping with static constants in the code that generates and interprets executables (that is, to reduce ambiguity for humans). - In the descriptions here, the width of a value (indicating, e.g., the range of a constant or the number of registers possibly addressed) is emphasized by the use of a character per four bits of width.
- For example, in the instruction
"
move-wide/from16 vAA, vBBBB
":- "
move
" is the base opcode, indicating the base operation (move a register's value). - "
wide
" is the name suffix, indicating that it operates on wide (64 bit) data. - "
from16
" is the opcode suffix, indicating a variant that has a 16-bit register reference as a source. - "
vAA
" is the destination register (implied by the operation; again, the rule is that destination arguments always come first), which must be in the rangev0
–v255
. - "
vBBBB
" is the source register, which must be in the rangev0
–v65535
.
- "
- See the instruction formats document for more details about the various instruction formats (listed under "Op & Format") as well as details about the opcode syntax.
- See the
.dex
file format document for more details about where the bytecode fits into the bigger picture.
Summary of bytecode set
Op & Format | Mnemonic / Syntax | Arguments | Description |
---|---|---|---|
00 10x | nop | Waste cycles.
Note:
Data-bearing pseudo-instructions are tagged with this opcode, in which
case the high-order byte of the opcode unit indicates the nature of
the data. See " |
|
01 12x | move vA, vB | A: destination register (4 bits)B: source register (4 bits) |
Move the contents of one non-object register to another. |
02 22x | move/from16 vAA, vBBBB | A: destination register (8 bits)B: source register (16 bits) |
Move the contents of one non-object register to another. |
03 32x | move/16 vAAAA, vBBBB | A: destination register (16 bits)B: source register (16 bits) |
Move the contents of one non-object register to another. |
04 12x | move-wide vA, vB | A: destination register pair (4 bits)B: source register pair (4 bits) |
Move the contents of one register-pair to another.
Note:
It is legal to move from |
05 22x | move-wide/from16 vAA, vBBBB | A: destination register pair (8 bits)B: source register pair (16 bits) |
Move the contents of one register-pair to another.
Note:
Implementation considerations are the same as |
06 32x | move-wide/16 vAAAA, vBBBB | A: destination register pair (16 bits)B: source register pair (16 bits) |
Move the contents of one register-pair to another.
Note:
Implementation considerations are the same as |
07 12x | move-object vA, vB | A: destination register (4 bits)B: source register (4 bits) |
Move the contents of one object-bearing register to another. |
08 22x | move-object/from16 vAA, vBBBB | A: destination register (8 bits)B: source register (16 bits) |
Move the contents of one object-bearing register to another. |
09 32x | move-object/16 vAAAA, vBBBB | A: destination register (16 bits)B: source register (16 bits) |
Move the contents of one object-bearing register to another. |
0a 11x | move-result vAA | A: destination register (8 bits) |
Move the single-word non-object result of the most recent
invoke-kind into the indicated register.
This must be done as the instruction immediately after an
invoke-kind whose (single-word, non-object) result
is not to be ignored; anywhere else is invalid. |
0b 11x | move-result-wide vAA | A: destination register pair (8 bits) |
Move the double-word result of the most recent
invoke-kind into the indicated register pair.
This must be done as the instruction immediately after an
invoke-kind whose (double-word) result
is not to be ignored; anywhere else is invalid. |
0c 11x | move-result-object vAA | A: destination register (8 bits) |
Move the object result of the most recent invoke-kind
into the indicated register. This must be done as the instruction
immediately after an invoke-kind or
filled-new-array
whose (object) result is not to be ignored; anywhere else is invalid. |
0d 11x | move-exception vAA | A: destination register (8 bits) |
Save a just-caught exception into the given register. This must be the first instruction of any exception handler whose caught exception is not to be ignored, and this instruction must only ever occur as the first instruction of an exception handler; anywhere else is invalid. |
0e 10x | return-void | Return from a void method. |
|
0f 11x | return vAA | A: return value register (8 bits) |
Return from a single-width (32-bit) non-object value-returning method. |
10 11x | return-wide vAA | A: return value register-pair (8 bits) |
Return from a double-width (64-bit) value-returning method. |
11 11x | return-object vAA | A: return value register (8 bits) |
Return from an object-returning method. |
12 11n | const/4 vA, #+B | A: destination register (4 bits)B: signed int (4 bits) |
Move the given literal value (sign-extended to 32 bits) into the specified register. |
13 21s | const/16 vAA, #+BBBB | A: destination register (8 bits)B: signed int (16 bits) |
Move the given literal value (sign-extended to 32 bits) into the specified register. |
14 31i | const vAA, #+BBBBBBBB | A: destination register (8 bits)B: arbitrary 32-bit constant |
Move the given literal value into the specified register. |
15 21h | const/high16 vAA, #+BBBB0000 | A: destination register (8 bits)B: signed int (16 bits) |
Move the given literal value (right-zero-extended to 32 bits) into the specified register. |
16 21s | const-wide/16 vAA, #+BBBB | A: destination register (8 bits)B: signed int (16 bits) |
Move the given literal value (sign-extended to 64 bits) into the specified register-pair. |
17 31i | const-wide/32 vAA, #+BBBBBBBB | A: destination register (8 bits)B: signed int (32 bits) |
Move the given literal value (sign-extended to 64 bits) into the specified register-pair. |
18 51l | const-wide vAA, #+BBBBBBBBBBBBBBBB | A: destination register (8 bits)B: arbitrary double-width (64-bit) constant |
Move the given literal value into the specified register-pair. |
19 21h | const-wide/high16 vAA, #+BBBB000000000000 | A: destination register (8 bits)B: signed int (16 bits) |
Move the given literal value (right-zero-extended to 64 bits) into the specified register-pair. |
1a 21c | const-string vAA, string@BBBB | A: destination register (8 bits)B: string index |
Move a reference to the string specified by the given index into the specified register. |
1b 31c | const-string/jumbo vAA, string@BBBBBBBB | A: destination register (8 bits)B: string index |
Move a reference to the string specified by the given index into the specified register. |
1c 21c | const-class vAA, type@BBBB | A: destination register (8 bits)B: type index |
Move a reference to the class specified by the given index into the specified register. In the case where the indicated type is primitive, this will store a reference to the primitive type's degenerate class. |
1d 11x | monitor-enter vAA | A: reference-bearing register (8 bits) |
Acquire the monitor for the indicated object. |
1e 11x | monitor-exit vAA | A: reference-bearing register (8 bits) |
Release the monitor for the indicated object.
Note:
If this instruction needs to throw an exception, it must do
so as if the pc has already advanced past the instruction.
It may be useful to think of this as the instruction successfully
executing (in a sense), and the exception getting thrown after
the instruction but before the next one gets a chance to
run. This definition makes it possible for a method to use
a monitor cleanup catch-all (e.g., |
1f 21c | check-cast vAA, type@BBBB | A: reference-bearing register (8 bits)B: type index (16 bits) |
Throw a ClassCastException if the reference in the
given register cannot be cast to the indicated type.
Note: Since |
20 22c | instance-of vA, vB, type@CCCC | A: destination register (4 bits)B: reference-bearing register (4 bits)C: type index (16 bits) |
Store in the given destination register 1
if the indicated reference is an instance of the given type,
or 0 if not.
Note: Since |
21 12x | array-length vA, vB | A: destination register (4 bits)B: array reference-bearing register (4 bits) |
Store in the given destination register the length of the indicated array, in entries |
22 21c | new-instance vAA, type@BBBB | A: destination register (8 bits)B: type index |
Construct a new instance of the indicated type, storing a reference to it in the destination. The type must refer to a non-array class. |
23 22c | new-array vA, vB, type@CCCC | A: destination register (4 bits)B: size registerC: type index |
Construct a new array of the indicated type and size. The type must be an array type. |
24 35c | filled-new-array {vC, vD, vE, vF, vG}, type@BBBB |
A: array size and argument word count (4 bits)B: type index (16 bits)C..G: argument registers (4 bits each)
|
Construct an array of the given type and size, filling it with the
supplied contents. The type must be an array type. The array's
contents must be single-word (that is,
no arrays of long or double , but reference
types are acceptable). The constructed
instance is stored as a "result" in the same way that the method invocation
instructions store their results, so the constructed instance must
be moved to a register with an immediately subsequent
move-result-object instruction (if it is to be used). |
25 3rc | filled-new-array/range {vCCCC .. vNNNN}, type@BBBB | A: array size and argument word count (8 bits)B: type index (16 bits)C: first argument register (16 bits)N = A + C - 1 |
Construct an array of the given type and size, filling it with
the supplied contents. Clarifications and restrictions are the same
as filled-new-array , described above. |
26 31t | fill-array-data vAA, +BBBBBBBB (with supplemental data as specified
below in "fill-array-data-payload Format") |
A: array reference (8 bits)B: signed "branch" offset to table data pseudo-instruction
(32 bits)
|
Fill the given array with the indicated data. The reference must be to an array of primitives, and the data table must match it in type and must contain no more elements than will fit in the array. That is, the array may be larger than the table, and if so, only the initial elements of the array are set, leaving the remainder alone. |
27 11x | throw vAA | A: exception-bearing register (8 bits) |
Throw the indicated exception. |
28 10t | goto +AA | A: signed branch offset (8 bits) |
Unconditionally jump to the indicated instruction.
Note:
The branch offset must not be |
29 20t | goto/16 +AAAA | A: signed branch offset (16 bits) |
Unconditionally jump to the indicated instruction.
Note:
The branch offset must not be |
2a 30t | goto/32 +AAAAAAAA | A: signed branch offset (32 bits) |
Unconditionally jump to the indicated instruction. |
2b 31t | packed-switch vAA, +BBBBBBBB (with supplemental data as
specified below in "packed-switch-payload Format") |
A: register to testB: signed "branch" offset to table data pseudo-instruction
(32 bits)
|
Jump to a new instruction based on the value in the given register, using a table of offsets corresponding to each value in a particular integral range, or fall through to the next instruction if there is no match. |
2c 31t | sparse-switch vAA, +BBBBBBBB (with supplemental data as
specified below in "sparse-switch-payload Format") |
A: register to testB: signed "branch" offset to table data pseudo-instruction
(32 bits)
|
Jump to a new instruction based on the value in the given register, using an ordered table of value-offset pairs, or fall through to the next instruction if there is no match. |
2d..31 23x | cmpkind vAA, vBB, vCC 2d: cmpl-float (lt bias) 2e: cmpg-float (gt bias) 2f: cmpl-double (lt bias) 30: cmpg-double (gt bias) 31: cmp-long |
A: destination register (8 bits)B: first source register or pairC: second source register or pair |
Perform the indicated floating point or long comparison,
setting a to 0 if b == c ,
1 if b > c ,
or -1 if b < c .
The "bias" listed for the floating point operations
indicates how NaN comparisons are treated: "gt bias"
instructions return 1 for NaN comparisons,
and "lt bias" instructions return -1 .
For example, to check to see if floating point
|
32..37 22t | if-test vA, vB, +CCCC 32: if-eq 33: if-ne 34: if-lt 35: if-ge 36: if-gt 37: if-le |
A: first register to test (4 bits)B: second register to test (4 bits)C: signed branch offset (16 bits) |
Branch to the given destination if the given two registers' values
compare as specified.
Note:
The branch offset must not be |
38..3d 21t | if-testz vAA, +BBBB 38: if-eqz 39: if-nez 3a: if-ltz 3b: if-gez 3c: if-gtz 3d: if-lez |
A: register to test (8 bits)B: signed branch offset (16 bits) |
Branch to the given destination if the given register's value compares
with 0 as specified.
Note:
The branch offset must not be |
3e..43 10x | (unused) | (unused) | |
44..51 23x | arrayop vAA, vBB, vCC 44: aget 45: aget-wide 46: aget-object 47: aget-boolean 48: aget-byte 49: aget-char 4a: aget-short 4b: aput 4c: aput-wide 4d: aput-object 4e: aput-boolean 4f: aput-byte 50: aput-char 51: aput-short |
A: value register or pair; may be source or dest
(8 bits)B: array register (8 bits)C: index register (8 bits) |
Perform the identified array operation at the identified index of the given array, loading or storing into the value register. |
52..5f 22c | iinstanceop vA, vB, field@CCCC 52: iget 53: iget-wide 54: iget-object 55: iget-boolean 56: iget-byte 57: iget-char 58: iget-short 59: iput 5a: iput-wide 5b: iput-object 5c: iput-boolean 5d: iput-byte 5e: iput-char 5f: iput-short |
A: value register or pair; may be source or dest
(4 bits)B: object register (4 bits)C: instance field reference index (16 bits) |
Perform the identified object instance field operation with
the identified field, loading or storing into the value register.
Note: These opcodes are reasonable candidates for static linking, altering the field argument to be a more direct offset. |
60..6d 21c | sstaticop vAA, field@BBBB 60: sget 61: sget-wide 62: sget-object 63: sget-boolean 64: sget-byte 65: sget-char 66: sget-short 67: sput 68: sput-wide 69: sput-object 6a: sput-boolean 6b: sput-byte 6c: sput-char 6d: sput-short |
A: value register or pair; may be source or dest
(8 bits)B: static field reference index (16 bits) |
Perform the identified object static field operation with the identified
static field, loading or storing into the value register.
Note: These opcodes are reasonable candidates for static linking, altering the field argument to be a more direct offset. |
6e..72 35c | invoke-kind {vC, vD, vE, vF, vG}, meth@BBBB 6e: invoke-virtual 6f: invoke-super 70: invoke-direct 71: invoke-static 72: invoke-interface |
A: argument word count (4 bits)B: method reference index (16 bits)C..G: argument registers (4 bits each)
|
Call the indicated method. The result (if any) may be stored
with an appropriate move-result* variant as the immediately
subsequent instruction.
When the In Dex files version
Note: These opcodes are reasonable candidates for static linking, altering the method argument to be a more direct offset (or pair thereof). |
73 10x | (unused) | (unused) | |
74..78 3rc | invoke-kind/range {vCCCC .. vNNNN}, meth@BBBB 74: invoke-virtual/range 75: invoke-super/range 76: invoke-direct/range 77: invoke-static/range 78: invoke-interface/range |
A: argument word count (8 bits)B: method reference index (16 bits)C: first argument register (16 bits)N = A + C - 1 |
Call the indicated method. See first invoke-kind
description above for details, caveats, and suggestions.
|
79..7a 10x | (unused) | (unused) | |
7b..8f 12x | unop vA, vB 7b: neg-int 7c: not-int 7d: neg-long 7e: not-long 7f: neg-float 80: neg-double 81: int-to-long 82: int-to-float 83: int-to-double 84: long-to-int 85: long-to-float 86: long-to-double 87: float-to-int 88: float-to-long 89: float-to-double 8a: double-to-int 8b: double-to-long 8c: double-to-float 8d: int-to-byte 8e: int-to-char 8f: int-to-short |
A: destination register or pair (4 bits)B: source register or pair (4 bits) |
Perform the identified unary operation on the source register, storing the result in the destination register. |
90..af 23x | binop vAA, vBB, vCC 90: add-int 91: sub-int 92: mul-int 93: div-int 94: rem-int 95: and-int 96: or-int 97: xor-int 98: shl-int 99: shr-int 9a: ushr-int 9b: add-long 9c: sub-long 9d: mul-long 9e: div-long 9f: rem-long a0: and-long a1: or-long a2: xor-long a3: shl-long a4: shr-long a5: ushr-long a6: add-float a7: sub-float a8: mul-float a9: div-float aa: rem-float ab: add-double ac: sub-double ad: mul-double ae: div-double af: rem-double |
A: destination register or pair (8 bits)B: first source register or pair (8 bits)C: second source register or pair (8 bits) |
Perform the identified binary operation on the two source registers,
storing the result in the destination register.
Note:
Contrary to other |
b0..cf 12x | binop/2addr vA, vB b0: add-int/2addr b1: sub-int/2addr b2: mul-int/2addr b3: div-int/2addr b4: rem-int/2addr b5: and-int/2addr b6: or-int/2addr b7: xor-int/2addr b8: shl-int/2addr b9: shr-int/2addr ba: ushr-int/2addr bb: add-long/2addr bc: sub-long/2addr bd: mul-long/2addr be: div-long/2addr bf: rem-long/2addr c0: and-long/2addr c1: or-long/2addr c2: xor-long/2addr c3: shl-long/2addr c4: shr-long/2addr c5: ushr-long/2addr c6: add-float/2addr c7: sub-float/2addr c8: mul-float/2addr c9: div-float/2addr ca: rem-float/2addr cb: add-double/2addr cc: sub-double/2addr cd: mul-double/2addr ce: div-double/2addr cf: rem-double/2addr |
A: destination and first source register or pair
(4 bits)B: second source register or pair (4 bits) |
Perform the identified binary operation on the two source registers,
storing the result in the first source register.
Note:
Contrary to other |
d0..d7 22s | binop/lit16 vA, vB, #+CCCC d0: add-int/lit16 d1: rsub-int (reverse subtract) d2: mul-int/lit16 d3: div-int/lit16 d4: rem-int/lit16 d5: and-int/lit16 d6: or-int/lit16 d7: xor-int/lit16 |
A: destination register (4 bits)B: source register (4 bits)C: signed int constant (16 bits) |
Perform the indicated binary op on the indicated register (first
argument) and literal value (second argument), storing the result in
the destination register.
Note:
|
d8..e2 22b | binop/lit8 vAA, vBB, #+CC d8: add-int/lit8 d9: rsub-int/lit8 da: mul-int/lit8 db: div-int/lit8 dc: rem-int/lit8 dd: and-int/lit8 de: or-int/lit8 df: xor-int/lit8 e0: shl-int/lit8 e1: shr-int/lit8 e2: ushr-int/lit8 |
A: destination register (8 bits)B: source register (8 bits)C: signed int constant (8 bits) |
Perform the indicated binary op on the indicated register (first
argument) and literal value (second argument), storing the result
in the destination register.
Note: See below for details on the semantics of
|
e3..f9 10x | (unused) | (unused) | |
fa 45cc | invoke-polymorphic {vC, vD, vE, vF, vG}, meth@BBBB, proto@HHHH |
A: argument word count (4 bits) B: method reference index (16 bits) C: receiver (4 bits) D..G: argument registers (4 bits each) H: prototype reference index (16 bits)
|
Invoke the indicated signature polymorphic method. The result (if any) may be stored
with an appropriate move-result* variant as the immediately
subsequent instruction.The method reference must be to a signature polymorphic method, such as java.lang.invoke.MethodHandle.invoke or
java.lang.invoke.MethodHandle.invokeExact .The receiver must be an object supporting the signature polymorphic method being invoked. The prototype reference describes the argument types provided and the expected return type. The invoke-polymorphic bytecode may raise exceptions when it
executes. The exceptions are described in the API documentation
for the signature polymorphic method being invoked.Present in Dex files from version 038 onwards.
|
fb 4rcc | invoke-polymorphic/range {vCCCC .. vNNNN}, meth@BBBB, proto@HHHH |
A: argument word count (8 bits) B: method reference index (16 bits) C: receiver (16 bits) H: prototype reference index (16 bits) N = A + C - 1
|
Invoke the indicated method handle. See the invoke-polymorphic
description above for details.Present in Dex files from version 038 onwards.
|
fc 35c | invoke-custom {vC, vD, vE, vF, vG}, call_site@BBBB |
A: argument word count (4 bits) B: call site reference index (16 bits) C..G: argument registers (4 bits each)
|
Resolves and invokes the indicated call site.
The result from the invocation (if any) may be stored with an
appropriate move-result* variant as the immediately
subsequent instruction.This instruction executes in two phases: call site resolution and call site invocation. Call site resolution checks whether the indicated call site has an associated java.lang.invoke.CallSite instance.
If not, the bootstrap linker method for the indicated call site is
invoked using arguments present in the DEX file
(see call_site_item). The
bootstrap linker method returns
a java.lang.invoke.CallSite instance that will then
be associated with the indicated call site if no association
exists. Another thread may have already made the association first,
and if so execution of the instruction continues with the
first associated java.lang.invoke.CallSite instance.Call site invocation is made on the java.lang.invoke.MethodHandle target of the resolved
java.lang.invoke.CallSite instance. The target is invoked as
if executing invoke-polymorphic (described above) using the
method handle and arguments to the invoke-custom instruction
as the arguments to an exact method handle invocation.Exceptions raised by the bootstrap linker method are wrapped in a java.lang.BootstrapMethodError . A
BootstrapMethodError is also raised if:
038 onwards.
|
fd 3rc | invoke-custom/range {vCCCC .. vNNNN}, call_site@BBBB |
A: argument word count (8 bits) B: call site reference index (16 bits) C: first argument register (16-bits) N = A + C - 1
|
Resolve and invoke a call site. See the invoke-custom
description above for details.Present in Dex files from version 038 onwards.
|
fe 21c | const-method-handle vAA, method_handle@BBBB | A: destination register (8 bits)B: method handle index (16 bits) |
Move a reference to the method handle specified by the given index into the
specified register. Present in Dex files from version 039 onwards.
|
ff 21c | const-method-type vAA, proto@BBBB | A: destination register (8 bits)B: method prototype reference (16 bits) |
Move a reference to the method prototype specified by the given index into the
specified register. Present in Dex files from version 039 onwards.
|
packed-switch-payload format
Name | Format | Description |
---|---|---|
ident | ushort = 0x0100 | identifying pseudo-opcode |
size | ushort | number of entries in the table |
first_key | int | first (and lowest) switch case value |
targets | int[] | list of size relative branch targets. The targets are
relative to the address of the switch opcode, not of this table.
|
Note: The total number of code units for an instance of this
table is (size * 2) + 4
.
sparse-switch-payload format
Name | Format | Description |
---|---|---|
ident | ushort = 0x0200 | identifying pseudo-opcode |
size | ushort | number of entries in the table |
keys | int[] | list of size key values, sorted low-to-high |
targets | int[] | list of size relative branch targets, each corresponding
to the key value at the same index. The targets are
relative to the address of the switch opcode, not of this table.
|
Note: The total number of code units for an instance of this
table is (size * 4) + 2
.
fill-array-data-payload format
Name | Format | Description |
---|---|---|
ident | ushort = 0x0300 | identifying pseudo-opcode |
element_width | ushort | number of bytes in each element |
size | uint | number of elements in the table |
data | ubyte[] | data values |
Note: The total number of code units for an instance of this
table is (size * element_width + 1) / 2 + 4
.
Mathematical operation details
Note: Floating point operations must follow IEEE 754 rules, using round-to-nearest and gradual underflow, except where stated otherwise.
Opcode | C Semantics | Notes |
---|---|---|
neg-int | int32 a; int32 result = -a; |
Unary twos-complement. |
not-int | int32 a; int32 result = ~a; |
Unary ones-complement. |
neg-long | int64 a; int64 result = -a; |
Unary twos-complement. |
not-long | int64 a; int64 result = ~a; |
Unary ones-complement. |
neg-float | float a; float result = -a; |
Floating point negation. |
neg-double | double a; double result = -a; |
Floating point negation. |
int-to-long | int32 a; int64 result = (int64) a; |
Sign extension of int32 into int64 . |
int-to-float | int32 a; float result = (float) a; |
Conversion of int32 to float , using
round-to-nearest. This loses precision for some values.
|
int-to-double | int32 a; double result = (double) a; |
Conversion of int32 to double . |
long-to-int | int64 a; int32 result = (int32) a; |
Truncation of int64 into int32 . |
long-to-float | int64 a; float result = (float) a; |
Conversion of int64 to float , using
round-to-nearest. This loses precision for some values.
|
long-to-double | int64 a; double result = (double) a; |
Conversion of int64 to double , using
round-to-nearest. This loses precision for some values.
|
float-to-int | float a; int32 result = (int32) a; |
Conversion of float to int32 , using
round-toward-zero. NaN and -0.0 (negative zero)
convert to the integer 0 . Infinities and values with
too large a magnitude to be represented get converted to either
0x7fffffff or -0x80000000 depending on sign.
|
float-to-long | float a; int64 result = (int64) a; |
Conversion of float to int64 , using
round-toward-zero. The same special case rules as for
float-to-int apply here, except that out-of-range values
get converted to either 0x7fffffffffffffff or
-0x8000000000000000 depending on sign.
|
float-to-double | float a; double result = (double) a; |
Conversion of float to double , preserving
the value exactly.
|
double-to-int | double a; int32 result = (int32) a; |
Conversion of double to int32 , using
round-toward-zero. The same special case rules as for
float-to-int apply here.
|
double-to-long | double a; int64 result = (int64) a; |
Conversion of double to int64 , using
round-toward-zero. The same special case rules as for
float-to-long apply here.
|
double-to-float | double a; float result = (float) a; |
Conversion of double to float , using
round-to-nearest. This loses precision for some values.
|
int-to-byte | int32 a; int32 result = (a << 24) >> 24; |
Truncation of int32 to int8 , sign
extending the result.
|
int-to-char | int32 a; int32 result = a & 0xffff; |
Truncation of int32 to uint16 , without
sign extension.
|
int-to-short | int32 a; int32 result = (a << 16) >> 16; |
Truncation of int32 to int16 , sign
extending the result.
|
add-int | int32 a, b; int32 result = a + b; |
Twos-complement addition. |
sub-int | int32 a, b; int32 result = a - b; |
Twos-complement subtraction. |
rsub-int | int32 a, b; int32 result = b - a; |
Twos-complement reverse subtraction. |
mul-int | int32 a, b; int32 result = a * b; |
Twos-complement multiplication. |
div-int | int32 a, b; int32 result = a / b; |
Twos-complement division, rounded towards zero (that is, truncated to
integer). This throws ArithmeticException if
b == 0 .
|
rem-int | int32 a, b; int32 result = a % b; |
Twos-complement remainder after division. The sign of the result
is the same as that of a , and it is more precisely
defined as result == a - (a / b) * b . This throws
ArithmeticException if b == 0 .
|
and-int | int32 a, b; int32 result = a & b; |
Bitwise AND. |
or-int | int32 a, b; int32 result = a | b; |
Bitwise OR. |
xor-int | int32 a, b; int32 result = a ^ b; |
Bitwise XOR. |
shl-int | int32 a, b; int32 result = a << (b & 0x1f); |
Bitwise shift left (with masked argument). |
shr-int | int32 a, b; int32 result = a >> (b & 0x1f); |
Bitwise signed shift right (with masked argument). |
ushr-int | uint32 a, b; int32 result = a >> (b & 0x1f); |
Bitwise unsigned shift right (with masked argument). |
add-long | int64 a, b; int64 result = a + b; |
Twos-complement addition. |
sub-long | int64 a, b; int64 result = a - b; |
Twos-complement subtraction. |
mul-long | int64 a, b; int64 result = a * b; |
Twos-complement multiplication. |
div-long | int64 a, b; int64 result = a / b; |
Twos-complement division, rounded towards zero (that is, truncated to
integer). This throws ArithmeticException if
b == 0 .
|
rem-long | int64 a, b; int64 result = a % b; |
Twos-complement remainder after division. The sign of the result
is the same as that of a , and it is more precisely
defined as result == a - (a / b) * b . This throws
ArithmeticException if b == 0 .
|
and-long | int64 a, b; int64 result = a & b; |
Bitwise AND. |
or-long | int64 a, b; int64 result = a | b; |
Bitwise OR. |
xor-long | int64 a, b; int64 result = a ^ b; |
Bitwise XOR. |
shl-long | int64 a; int32 b; int64 result = a << (b & 0x3f); |
Bitwise shift left (with masked argument). |
shr-long | int64 a; int32 b; int64 result = a >> (b & 0x3f); |
Bitwise signed shift right (with masked argument). |
ushr-long | uint64 a; int32 b; int64 result = a >> (b & 0x3f); |
Bitwise unsigned shift right (with masked argument). |
add-float | float a, b; float result = a + b; |
Floating point addition. |
sub-float | float a, b; float result = a - b; |
Floating point subtraction. |
mul-float | float a, b; float result = a * b; |
Floating point multiplication. |
div-float | float a, b; float result = a / b; |
Floating point division. |
rem-float | float a, b; float result = a % b; |
Floating point remainder after division. This function is different
than IEEE 754 remainder and is defined as
result == a - roundTowardZero(a / b) * b .
|
add-double | double a, b; double result = a + b; |
Floating point addition. |
sub-double | double a, b; double result = a - b; |
Floating point subtraction. |
mul-double | double a, b; double result = a * b; |
Floating point multiplication. |
div-double | double a, b; double result = a / b; |
Floating point division. |
rem-double | double a, b; double result = a % b; |
Floating point remainder after division. This function is different
than IEEE 754 remainder and is defined as
result == a - roundTowardZero(a / b) * b .
|