【JAVA】虚拟机指令集

JVM指令助记符

• 变量到操作数栈：iload,iload_,lload,lload_,fload,fload_,dload,dload_,aload,aload_
• 操作数栈到变量：istore,istore_,lstore,lstore_,fstore,fstore_,dstore,dstor_,astore,astore_
• 常数到操作数栈：bipush,sipush,ldc,ldc_w,ldc2_w,aconst_null,iconst_ml,iconst_,lconst_,fconst_,dconst_
• 加：iadd,ladd,fadd,dadd
• 减：is ,ls ,fs ,ds
• 乘：imul,lmul,fmul,dmul
• 除：idiv,ldiv,fdiv,ddiv
• 余数：irem,lrem,frem,drem
• 取负：ineg,lneg,fneg,dneg
• 移位：ishl,lshr,iushr,lshl,lshr,lushr
• 按位或：ior,lor
• 按位与：iand,land
• 按位异或：ixor,lxor

• 类型转换：i2l,i2f,i2d,l2f,l2d,f2d(放宽数值转换)
  i2b,i2c,i2s,l2i,f2i,f2l,d2i,d2l,d2f(缩窄数值转换)

• 创建类实便：new

• 创建新数组：newarray,anewarray,multianwarray
• 访问类的域和类实例域：getfield,putfield,getstatic,putstatic
• 把数据装载到操作数栈：baload,caload,saload,iaload,laload,faload,daload,aaload
• 从操作数栈存存储到数组：bastore,castore,sastore,iastore,lastore,fastore,dastore,aastore
• 获取数组长度：arraylength
• 检相类实例或数组属性：instanceof,checkcast
• 操作数栈管理：pop,pop2,dup,dup2,dup_xl,dup2_xl,dup_x2,dup2_x2,swap
• 有条件转移：ifeq,iflt,ifle,ifne,ifgt,ifge,ifnull,ifnonnull,if_icmpeq,if_icmpene,
  if_icmplt,if_icmpgt,if_icmple,if_icmpge,if_acmpeq,if_acmpne,lcmp,fcmpl
  fcmpg,dcmpl,dcmpg
• 复合条件转移：tableswitch,lookupswitch
• 无条件转移：goto,goto_w,jsr,jsr_w,ret
• 调度对象的实便方法：invokevirt l
• 调用由接口实现的方法：invokeinterface
• 调用需要特殊处理的实例方法：invokespecial
• 调用命名类中的静态方法：invokestatic
• 方法返回：ireturn,lreturn,freturn,dreturn,areturn,return
• 异常：athrow
• finally关键字的实现使用：jsr,jsr_w,ret
  

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【javap】

-help
Prints out help message for javap.
-l
Prints out line and local variable tables.
-b
Ensures backward compatibility with javap in JDK 1.1.
-p lic
Shows only p lic classes and members.
-protected
Shows only protected and p lic classes and members.
-package
Shows only package, protected, and p lic classes and members. This is the default.
-private
Shows all classes and members.
-Jflag
Pass flag directly to the runtime system. Some examples:

javap -J-version  javap -J-Djava.security.manager -J-Djava.security.policy=MyPolicy MyClassName

-s
Prints internal type signatures.
-c
Prints out disassembled code, i.e., the instr tions that comprise the Java bytecodes, for each of the methods in the class. These are documented in the Java Virt l Machine Specification.
-verbose
Prints stack size, number of
locals
and
args
for methods.
-classpath path
Specifies the path javap uses to look up classes. Overrides the default or the CLASSPATH environment variable if it is set. Directories are separated by semi-colons. Thus the general format for path is:

   .;<your_path>  For example:.;C:\usrs\dac\classes;C:\tools\java\classes

-bootclasspath path
Specifies path from which to load bootstrap classes. By default, the bootstrap classes are the classes implementing the core Java platform located in jre\lib\rt.jar and several other jar files.
-extdirs dirs
Overrides location at which installed extensions are searched for. The default location for extensions is the val of java.ext.dirs.