A brief introduction to Smali syntax

Smali language is actually the register language of Davlik;

The Smali language is the Android app. The APK is compiled with a Smali folder in Apktool, which is a file that ends in. Smali, and the file's display language.

The Smali syntax is briefly described as follows :

Davlik bytecode, registers are 32-bit, can support any type, 64-bit type (long/double) is represented by 2 registers;

There are two types of Dalvik bytecode: primitive type; reference type (including objects and arrays)

Primitive Type:v void can only be used for return value types

Z Boolean

B byte

S Short

C Char

I int

J Long (64-bit)

F float

D double (64-bit)

Object type : Lpackage/name/objectname; Equivalent to Package.name.ObjectName in Java, as explained below:

L: Indicates that this is an object type

Package/name: The package in which the object resides

;: Indicates the end of the object name

representation of the array:

[I : Represents a shaped one-dimensional array, equivalent to the Java int[];

for multidimensional arrays, just add [ on the line,[I = int[]; note: A maximum of 255 per dimension;

Representation of an array of objects:

[Ljava/lang/string represents an array of objects of a String;

Representation of the method:

lpackage/name/objectname;-->methodname (III) Z is detailed below:

Lpackage/name/objectname expression type

MethodName represents the method name

III represents the parameter (represented here as 3 integer parameters)

Note: The parameters of the method are one after the other, the middle is not separated;

representation of a field:

lpackage/name/objectname;-->fieldname:ljava/lang/string;

That means: Package name, field name, and field type

There are two ways to specify how many registers are available in a method:

The. Registers directive specifies the total number of registers in the method

The. Locals instruction shows the total number of non-parameter registers in the method, appearing in the first line of the method

Parameter of the method:

When a method is called, the parameters of the method are placed in the last n registers;

For example, a method has 2 parameters, 5 registers (V0~V4)

Then, the parameter will be placed in the last 2 registers (V3 and V4)

The first parameter in a non-static method always calls the object of the method;

Description: For static methods other than the implied this parameter, the others are the same

How registers are named:

V naming

P Naming the first register is the first parameter register in a method

Comparison: The use of the P name is to prevent later if the register is added in the method, it is necessary to re-numbering the parameter register disadvantage

In particular: long and double types are 64-bit and require 2 registers

For example, for non-static methods

Lmyobject-->mymethod (IJZ) V;

There are 4 parameters: Lmyobject,int,long,bool; 5 registers are required to store the parameters;

P0 this

P1 I (int)

P2,P3 J (Long)

P4 Z (BOOL)

A brief introduction to Smali syntax