継続は力にゃりん。毎日続けることができるのか？

進捗
* 2005-11-24 中断
* 2005-11-15 いろいろ
* 2005-11-10 Class
* 2005-11-05 Method
* 2005-11-03 Subroutines
* 2005-11-01 Switches
* 2005-10-10 Control Instructions
* 2005-10-09 Just Biding Your Time
* 2005-09-30 Arrays of Numbers
* 2005-09-20 Stack Manipulations
* 2005-09-15 Type Conversions
* 2005-09-13 Bitwise Operation
* 2005-09-11 Nonnumbers and Infinity
* 2005-09-07 Arithmetic operations
* 2005-08-26 load, store
* 2005-08-23 複数 println
* 2005-08-21 push
* 2005-08-10 *const_*
* 2005-08-06 ldc* と println
* 2005-08-01 start

!2005-11-23 Wed

  .class public C2005112300
  .super java/lang/Object
  
  .method static foo(I)V
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_0
    invokevirtual java/io/PrintStream/println (I)V
    return
  .end method
  
  .method static foo(I)V
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_0
    invokevirtual java/io/PrintStream/println (I)V
    return
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 1
    invokestatic C2005112300/foo(I)V
  
    return
  
  .end method
  .end class
で、コンパイルは通ってしまい、実行は、
  Exception in thread "main" java.lang.ClassFormatError: Repetitive method name/signature in class file C2005112300

!2005-11-22 Tue

  .class public C2005112200
  .super java/lang/Object
  
  .method static foo(I)V
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_0
    invokevirtual java/io/PrintStream/println (I)V
    return
  .end method
  
  .method static foo(II)V
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_0
    iload_1
    iadd
    invokevirtual java/io/PrintStream/println (I)V
    return
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 1
    invokestatic C2005112200/foo(I)V
  
    ldc 1
    ldc 2
    invokestatic C2005112200/foo(II)V
  
    return
  
  .end method
  .end class
で、
  1
  3

!2005-11-21 Mon

  .class public C2005112100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 5
  
    iconst_5
    newarray char
    dup
    iconst_0
    bipush 72
    castore
    dup
    iconst_1
    bipush 101
    castore
    dup
    iconst_2
    bipush 108
    castore
    dup
    iconst_3
    bipush 108
    castore
    dup
    iconst_4
    bipush 111
    castore
    astore_1
    getstatic java/lang/System/out Ljava/io/PrintStream;
    new java/lang/String
    dup
    aload_1
    invokespecial	java/lang/String/<init> ([C)V
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  .end class
で、
  Hello

!2005-11-20 Sun

  .class public C2005112000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "Hello, World!!"
    ldc 0
    invokevirtual java/lang/String/charAt (I)C
    invokevirtual java/io/PrintStream/println (C)V
  
    return
  
  .end method
  .end class
で、
  H

!2005-11-19 Sat

  .class public C2005111900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 5
  
    iconst_3
    newarray int
    dup
    iconst_0
    iconst_1
    iastore
    dup
    iconst_1
    iconst_2
    iastore
    dup
    iconst_2
    iconst_3
    iastore
    arraylength
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  3

!2005-11-18 Fri

  .class public C2005111800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc 1
     invokevirtual java/io/PrintStream/println (Z)V
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc 0
     invokevirtual java/io/PrintStream/println (Z)V
     return
  
  .end method
  .end class
で、
  true
  false

boolean 型なのに、なぜ数値 ???

!2005-11-17 Thu

  .class public C2005111700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc 65
     invokevirtual java/io/PrintStream/println (C)V
     return
  
  .end method
  .end class
で、
  A

!2005-11-16 Wed

  .class public C2005111600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 5
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 2.0
    ldc2_w 3.0
    invokestatic java/lang/Math/pow (DD)D
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  8.0

!2005-11-15 Tue

  .class public C2005111500
  .super java/lang/Object
  
  .method static read_num()I
  .throws java/io/IOException
  
    new java/io/BufferedReader
    dup
    new java/io/InputStreamReader
    dup
    getstatic java/lang/System/in Ljava/io/InputStream;
    invokespecial java/io/InputStreamReader/<init> (Ljava/io/InputStream;)V
    invokespecial java/io/BufferedReader/<init> (Ljava/io/Reader;)V
    astore_0
    aload_0
    invokevirtual java/io/BufferedReader/readLine()Ljava/lang/String;
    invokestatic  java/lang/Integer/parseInt (Ljava/lang/String;)I
  
    ireturn
  
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    invokestatic C2005111500/read_num()I
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  1
  1

!2005-11-14 Mon

  .class C20051114
  .super java/lang/Object
  
  .field x I
  
  .method <init>()V
    aload_0
    invokespecial java/lang/Object/<init> ()V
    return
  .end method
  
  .method public set_x(I)V
    aload_0
    iload_1
    putfield C20051114/x I
    return
  .end method
  
  .method public get_x()I
    aload_0
    getfield C20051114/x I
    ireturn
  .end method
  .end class
  
  
  .class public C2005111400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    new C20051114
    dup
    invokespecial C20051114/<init> ()V
    astore_2
    aload_2
  
    ldc 10
    invokevirtual C20051114/set_x (I)V
  
    aload_2
    invokevirtual C20051114/get_x ()I
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  10

!2005-11-13 Sun

  .class C20051113
  .super java/lang/Object
  
  .method <init>()V
    aload_0
    invokespecial java/lang/Object/<init> ()V
    return
  .end method
  
  .method public foo()V
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  .end method
  .end class
  
  
  .class public C2005111300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    new C20051113
    dup
    invokespecial C20051113/<init> ()V
  
    invokevirtual C20051113/foo ()V
  
    return
  
  .end method
  .end class
で、
  foo

!2005-11-12 Sat

こんなのを
  class C20051112
  {
      C20051112() {}
  
      public void foo()
      {
          System.out.println("foo");
      }
  }
用意して、
  .class public C2005111200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    new C20051112
    dup
    invokespecial C20051112/<init> ()V
  
    invokevirtual C20051112/foo ()V
  
    return
  
  .end method
  .end class
で、
  foo

!2005-11-11 Fri

  .class public C2005111100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    new java/lang/Integer
    dup
    bipush 123
    invokespecial java/lang/Integer/<init> (I)V
  
    invokevirtual java/lang/Integer/intValue ()I
    invokestatic java/lang/Integer/toString (I)Ljava/lang/String;
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  .end class
で、
  123

!2005-11-10 Thu

  .class public C2005111000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    bipush 123
    invokestatic java/lang/Integer/toString (I)Ljava/lang/String;
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  .end class
で、
  123

!2005-11-09 Wed

  .class public C2005110900
  .super java/lang/Object
  
  .method static foo(II)I
  
    iload_0
    iload_1
    iadd
  
    ireturn
  
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    invokestatic C2005110900/foo(II)I
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  3

!2005-11-08 Tue

  .class public C2005110800
  .super java/lang/Object
  
  .method static foo(I)I
  
    iload_0
    bipush 1
    iadd
  
    ireturn
  
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    invokestatic C2005110800/foo(I)I
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  2

!2005-11-07 Mon

  .class public C2005110700
  .super java/lang/Object
  
  .method static foo(I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_0
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    ldc 1
    invokestatic C2005110700/foo(I)V
  
    return
  
  .end method
  .end class
で、
  1

!2005-11-06 Sun

  .class public C2005110600
  .super java/lang/Object
  
  .method static foo()V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    invokestatic C2005110600/foo()V
  
    return
  
  .end method
  .end class
で、
  foo

!2005-11-05 Sat

  .class public C2005110500
  .super java/lang/Object
  
  .method public static foo()V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    invokestatic C2005110500/foo()V
  
    return
  
  .end method
  .end class
で、
  foo

!2005-11-04 Fri

  .class public C2005110400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    jsr hoge
    return
  
  hoge:
    astore_0
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "Hello World"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    ret 0
  
  .end method
  .end class
で、
  Hello World

まだ完全には理解できていないが、かなり苦労したよ〜

!2005-11-03 Thu

  .class public C2005110300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ;.limit stack 2
  ; OK
  .limit stack 3
  
    jsr hoge
    return
  
  hoge:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "in hoge"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  in hoge

return しちゃったら、main を終了してしまっている気がするなあ。ダメじゃん。

!2005-11-02 Wed

  .class public C2005110200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 1
    i2l
    ldc 1
    i2l
    lcmp
    tableswitch -1
      less
      equal
      greater
      default: fail
  
  less:
    ldc "<"
    astore_0
    goto print
  
  equal:
    ldc "=="
    astore_0
    goto print
  
  greater:
    ldc ">"
    astore_0
    goto print
  
  print:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
  fail:
  
    return
  
  .end method
  .end class
で、
  ==

!2005-11-01 Tue

  .class public C2005110100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 1
    i2l
    ldc 1
    i2l
    lcmp
    lookupswitch
      -1:       less
       0:       equal
       1:       greater
       default: fail
  
  less:
    ldc "<"
    astore_0
    goto print
  
  equal:
    ldc "=="
    astore_0
    goto print
  
  greater:
    ldc ">"
    astore_0
    goto print
  
  print:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
  fail:
  
    return
  
  .end method
  .end class
で、
  ==

なんだか分からないけど、
  .class public C2005110101
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 5
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    ldc 1
    i2l
    ldc 1
    i2l
    lcmp
    lookupswitch
      -1:       less
       0:       equal
       1:       greater
       default: fail
  
  less:
    ldc "<"
    goto print
  
  equal:
    ldc "=="
    goto print
  
  greater:
    ldc ">"
    goto print
  
  print:
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
  fail:
  
    return
  
  .end method
  .end class
だと、
  Exception in thread "main" java.lang.VerifyError: (class: C2005110101, method: main signature: ([Ljava/lang/String;)V) Inconsistent stack height 0 != 1
なぞと怒られてしまう

!2005-10-31 Mon

  .class public C2005103100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    ldc2_w 1
    ldc2_w 10
    lcmp
  
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  -1

!2005-10-30 Sun

  .class public C2005103000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ;.limit stack 5
  .limit stack 6
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    getstatic java/lang/Math/PI D
    d2f
    dconst_1
    dconst_0
    ddiv
    d2f
    fcmpg
  
    invokevirtual java/io/PrintStream/println (I)V
  
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    getstatic java/lang/Math/PI D
    d2f
    dconst_1
    dconst_0
    ddiv
    d2f
    fcmpl
  
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  -1
  -1

!2005-10-29 Sat

  .class public C2005102900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ;.limit stack 3
  .limit stack 4
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    getstatic java/lang/Math/PI D
    d2f
    ldc2_w 3.1416D
    d2f
    fcmpg
  
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  -1

!2005-10-28 Fri

  .class public C2005102800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ;.limit stack 6
  .limit stack 7
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    getstatic java/lang/Math/PI D
    dconst_1
    dconst_0
    ddiv
    dcmpg
  
    invokevirtual java/io/PrintStream/println (I)V
  
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    getstatic java/lang/Math/PI D
    dconst_1
    dconst_0
    ddiv
    dcmpl
  
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  -1
  -1

dcmpg, dcmpl 違いがないなあ？

!2005-10-27 Thu

  .class public C2005102700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ;.limit stack 4
  .limit stack 5
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
  
    getstatic java/lang/Math/PI D
    ldc2_w 3.1416D
    dcmpg
  
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  -1

!2005-10-26 Wed

  .class public C2005102600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ;.limit stack 3
  .limit stack 4
  
    getstatic java/lang/Math/PI D
    ldc2_w 3.1416D
    dcmpg
    iflt approxTooHigh
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "PI >= 3.1416"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  approxTooHigh:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "PI < 3.1416"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  PI < 3.1416

!2005-10-25 Tue

  .class public C2005102500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ;ldc "foo"
    aconst_null
    ifnonnull non_null
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "null"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  non_null:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "not null"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  null

!2005-10-24 Mon

  .class public C2005102400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc "foo"
    ifnull null
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "not null"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  null:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "null"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  not null

!2005-10-23 Sun

  .class public C2005102300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc "foo"
    ldc "foo"
    if_acmpne acmp
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo == foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  acmp:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo != foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  foo == foo

!2005-10-22 Sat

  .class public C2005102200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc "foo"
    ldc "foo"
    if_acmpeq acmp
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo != foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  acmp:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "foo == foo"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  foo == foo

あれ？同じなんだ

!2005-10-21 Fri

  .class public C2005102100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    ifne not_equal
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 == 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  not_equal:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 != 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 != 0

!2005-10-20 Thu

  .class public C2005102000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    ifeq equal
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 != 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  equal:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 == 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 != 0

!2005-10-19 Wed

  .class public C2005101900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    ifle lesser
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 > 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  lesser:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 <= 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 > 0

!2005-10-18 Tue

  .class public C2005101800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    iflt lesser
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 >= 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  lesser:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 < 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 >= 0

!2005-10-17 Mon

  .class public C2005101700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    ifge greater
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 < 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  greater:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 >= 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 >= 0

!2005-10-16 Sun

  .class public C2005101600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    ifgt greater
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 <= 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  greater:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 > 0"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 > 0

!2005-10-15 Sat

  .class public C2005101500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    bipush 10
    if_icmpne not_equal
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 == 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  not_equal:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 != 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 != 10

!2005-10-14 Fri

  .class public C2005101400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    bipush 10
    if_icmpeq equal
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 != 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  equal:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 == 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 != 10

!2005-10-13 Thu

  .class public C2005101300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    bipush 10
    if_icmple lesser
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 > 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  lesser:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 <= 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 <= 10

!2005-10-12 Wed

  .class public C2005101200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    bipush 10
    if_icmplt lesser
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 >= 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  lesser:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 < 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 < 10

!2005-10-11 Tue

  .class public C2005101100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    bipush 10
    if_icmpge greater
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 < 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  greater:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 >= 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 < 10

!2005-10-10 Mon

  .class public C2005101000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    bipush 1
    bipush 10
    if_icmpgt greater
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 <= 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  greater:
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "1 > 10"
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  1 <= 10

!2005-10-09 Sun

multianewarray とばし。
ってどういう時に使うのか、良く分からないから。

  .class public C2005100900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    nop
    nop
    nop
  
    return
  
  .end method
  .end class

で、javap で確かめると、

  Compiled from 2005100900.j
  public class C2005100900 extends java.lang.Object 
      /* ACC_SUPER bit NOT set */
  {
      public static void main(java.lang.String[]);
  }
  
  Method void main(java.lang.String[])
     0 nop
     1 nop
     2 nop
     3 return

!2005-10-08 Sat

  .class public C2005100800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    anewarray java/lang/String
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ldc "a"
    aastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    aaload
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  .end class
で、
  a

!2005-10-07 Fri

  .class public C2005100700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray char
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ldc 10
    i2c
    castore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    caload
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  10

!2005-10-06 Thu

  .class public C2005100600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray byte
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ldc 10
    i2b
    bastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    baload
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  10

!2005-10-05 Wed

  .class public C2005100500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray double
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ldc2_w 1.2D
    dastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    daload
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  1.2

!2005-10-04 Tue

  .class public C2005100400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray float
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ;ldc 1.2
    ldc2_w 1.2D
    d2f
    fastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    faload
    invokevirtual java/io/PrintStream/println (F)V
  
    return
  
  .end method
  .end class
で、
  1.2

!2005-10-03 Mon

  .class public C2005100300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray short
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ldc 10
    i2s
    sastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    saload
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  10

考えてみると、short を (I) で表示して大丈夫なんだろうか？

!2005-10-02 Sun

  .class public C2005100200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray long
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ;ldc 10
    ldc2_w 10L
    lastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    laload
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  10

!2005-10-01 Sat

  .class public C2005100101
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 3
    newarray int
    astore_0
    aload_0
  
    ; set variable
    ldc 0
    ldc 10
    iastore
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    ldc 0
    iaload
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  10

!2005-09-30 Fri

  .class public C2005093000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 10
    newarray int
    ;astore_0
    ;aload_0
  
    ldc 1
    iaload
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  0

!2005-09-29 Thu

  .class public C2005092900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    ldc2_w 2L
    ldc2_w 3L
    dup2_x2
    ladd
    ladd
    ladd
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  9

!2005-09-28 Wed

  .class public C2005092800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc2_w 2L
    dup2_x1
    l2i
    isub
    i2l
    ladd
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  1

!2005-09-27 Tue

  .class public C2005092700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    dup2
    ladd
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  2

!2005-09-26 Mon

  .class public C2005092600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    ldc 3
    dup_x2
    iadd
    iadd
    iadd
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  9

!2005-09-25 Sun

  .class public C2005092500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    dup_x1
    isub
    iadd
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    dup_x1
    iadd
    iadd
    invokevirtual java/io/PrintStream/println (I)V
  
  
    ldc "O"
    ldc "S"
    dup_x1
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    swap
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  .end class
で、
  1
  5
  S
  O
  S

!2005-09-24 Sat

  .class public C2005092400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    dup
    iadd
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  2

!2005-09-23 Fri

  .class public C2005092300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    swap
    isub
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  1

!2005-09-22 Thu

  .class public C2005092200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc2_w 1L
    pop2
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  1

!2005-09-21 Wed

  .class public C2005092100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    ldc 3
    pop2
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  1

!2005-09-20 Tue

  .class public C2005092000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 2
    pop
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  1

!2005-09-19 Mon

  .class public C2005091900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ; .limit stack 2
  ; OK
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.2
    d2i
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.2
    d2l
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.2
    d2f
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.2D
    d2f
    invokevirtual java/io/PrintStream/println (F)V
  
    return
  
  .end method
  .end class
で、
  1
  1
  1.2
  1.2

!2005-09-18 Sun

  .class public C2005091800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ; .limit stack 2
  ; OK
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    f2i
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    f2l
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    f2d
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  1
  1
  1.0

ldc 1.2 だと以下のエラー
  invalid argument to ldc
今まで気がつかなかったが、.0 しか使っていなかったからのよう。
未解決。

!2005-09-17 Sat

  .class public C2005091700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ; .limit stack 2
  ; OK
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    l2i
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    l2f
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    l2d
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  1
  1.0
  1.0

!2005-09-16 Fri

  .class public C2005091600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ; .limit stack 2
  ; OK
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x7fff
    i2b
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x7f
    i2b
    invokevirtual java/io/PrintStream/println (I)V
  
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x7fffffff
    i2c
    invokevirtual java/io/PrintStream/println (I)V
  
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x7fffffff
    i2s
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x7fff
    i2s
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  -1
  127
  65535
  -1
  32767

0xffff をなぜ 65535 と表示するんだろう？

!2005-09-15 Thu

  .class public C2005091500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; NG
  ; .limit stack 2
  ; OK
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    i2l
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    i2f
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    i2d
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  10
  10.0
  10.0

stack size を指定しないと、実行時エラーに

!2005-09-14 Wed

  .class public C2005091400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    ;ldc2_w 3L
    ldc 3
    lshl
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 16
    ldc 3
    lshr
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w -1
    ldc 3
    lshr
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w -1
    ldc 3
    lushr
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    ldc2_w 3L
    land
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    ldc2_w 3L
    lor
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    ldc2_w 3L
    lxor
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  8
  2
  -1
  2305843009213693951
  1
  3
  2

シフト量が long だと実行時エラーになってしまうようだ

  ldc2_w 0x80000000
というように書くとコンパイルできない。
16進で書けないの？？？

!2005-09-13 Tue

  .class public C2005091300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 3
    ishl
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 8
    ldc 3
    ishr
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x80000000
    ldc 3
    ishr
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 0x80000000
    ldc 3
    iushr
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 3
    iand
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 3
    ior
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ldc 3
    ixor
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  8
  1
  -268435456
  268435456
  1
  3
  2

「ldc 0x80000000」を「ldc 2147483648」と書くと、実行時エラーに。なぜ？

!2005-09-12 Mon

  .class public C2005091200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_1
    fconst_0
    fdiv
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_1
    fconst_0
    fdiv
    fconst_1
    fadd
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_1
    fconst_0
    fdiv
    dup
    fsub
    invokevirtual java/io/PrintStream/println (F)V
  
    return
  
  .end method
  .end class
で、
  Infinity
  Infinity
  NaN

!2005-09-11 Sun

  .class public C2005091100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_0
    fconst_0
    fdiv
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_0
    fconst_0
    fdiv
    fconst_0
    fadd
    invokevirtual java/io/PrintStream/println (F)V
  
    return
  
  .end method
  .end class
で、
  NaN
  NaN

!2005-09-10 Sat

  .class public C2005091000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.0
    dconst_1
    dadd
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.0
    ldc2_w 2.0
    dadd
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.0
    ldc2_w 2.0
    dadd
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 2.0
    ldc2_w 1.0
    dsub
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 2.0
    ldc2_w 3.0
    dmul
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 10.0
    ldc2_w 3.0
    ddiv
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 10.0
    ldc2_w 3.0
    drem
    invokevirtual java/io/PrintStream/println (D)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1.0
    dneg
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  2.0
  3.0
  3.0
  1.0
  6.0
  3.3333333333333335
  1.0
  -1.0

!2005-09-09 Fri

  .class public C2005090900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    ldc 1.0
    fadd
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 2.0
    ldc 1.0
    fsub
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 2.0
    ldc 3.0
    fmul
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 10.0
    ldc 3.0
    fdiv
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 10.0
    ldc 3.0
    frem
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    fneg
    invokevirtual java/io/PrintStream/println (F)V
  
    return
  
  .end method
  .end class
で、
  2.0
  1.0
  6.0
  3.3333333
  1.0
  -1.0

!2005-09-08 Thu

  .class public C2005090800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    lconst_1
    ladd
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    ldc2_w 2L
    ladd
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1
    ldc2_w 2
    ladd
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 2
    ldc2_w 1
    lsub
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 2
    ldc2_w 3
    lmul
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 10
    ldc2_w 3
    ldiv
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 10
    ldc2_w 3
    lrem
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1
    lneg
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  2
  3
  3
  1
  6
  3
  1
  -1

!2005-09-07 Wed

  .class public C2005090700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    bipush 1
    iadd
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 2
    bipush 1
    isub
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 2
    bipush 3
    imul
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 10
    bipush 3
    idiv
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 10
    bipush 3
    irem
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    ineg
    invokevirtual java/io/PrintStream/println (I)V
  
    return
  
  .end method
  .end class
で、
  2
  1
  6
  3
  1
  -1

!2005-09-06 Tue

  .class public C2005090600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    dconst_0
    dstore_0
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    dload_0
    invokevirtual java/io/PrintStream/println (D)V
  
    dconst_1
    dstore_1
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    dload_1
    invokevirtual java/io/PrintStream/println (D)V
  
    return
  
  .end method
  .end class
で、
  0.0
  1.0

!2005-09-05 Mon

  .class public C2005090500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    dconst_1
    dstore 0
    dload  0
    invokevirtual java/io/PrintStream/println (D)V
    return
  
  .end method
  .end class
で、
  1.0

!2005-09-04 Sun

  .class public C2005090400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc2_w 0L
    lstore_0
  
    ldc2_w 2L
    lstore_2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    lload_0
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    lload_2
    invokevirtual java/io/PrintStream/println (J)V
  
    ldc2_w 1L
    lstore_1
  
    ldc2_w 3L
    lstore_3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    lload_1
    invokevirtual java/io/PrintStream/println (J)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    lload_3
    invokevirtual java/io/PrintStream/println (J)V
  
    return
  
  .end method
  .end class
で、
  0
  2
  1
  3

良く分かっていないが、近接している箇所を連続して使用すると、
エラーになってしまうようだ。

long の場合、2つ分使用するのが関係していそう。
破壊しちゃうのかな？？？

!2005-09-03 Sat

  .class public C2005090300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 0L
    lstore_0
    lload_0
    invokevirtual java/io/PrintStream/println (J)V
    return
  
  .end method
  .end class
で、
  0

!2005-09-02 Fri

  .class public C2005090200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc "foo 0"
    astore_0
  
    ldc "foo 1"
    astore_1
  
    ldc "foo 2"
    astore_2
  
    ldc "foo 3"
    astore_3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_0
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_1
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_2
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    aload_3
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
  
    return
  
  .end method
  .end class
で、
  foo 0
  foo 1
  foo 2
  foo 3

!2005-09-01 Thu

  .class public C2005090100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc "Hello, World"
    astore 0
    aload  0
    invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
    return
  
  .end method
  .end class
で、
  Hello, World

!2005-08-31 Wed

  .class public C2005083100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    fconst_0
    fstore_0
  
    fconst_1
    fstore_1
  
    fconst_2
    fstore_2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fload_0
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fload_1
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fload_2
    invokevirtual java/io/PrintStream/println (F)V
  
  
    fconst_0
    fstore_0
  
    fconst_1
    fstore_1
  
    fconst_2
    fstore_2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fload_2
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fload_1
    invokevirtual java/io/PrintStream/println (F)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fload_0
    invokevirtual java/io/PrintStream/println (F)V
  
    return
  
  .end method
  .end class
で、
  0.0
  1.0
  2.0
  2.0
  1.0
  0.0

!2005-08-30 Tue

  .class public C2005083000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_1
    fstore 0
    fload  0
    invokevirtual java/io/PrintStream/println (F)V
    return
  
  .end method
  .end class
で、
  1.0

!2005-08-29 Mon

  .class public C2005082900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    ldc 0
    istore_0
  
    ldc 1
    istore_1
  
    ldc 2
    istore_2
  
    ldc 3
    istore_3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_0
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_1
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_2
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iload_3
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  0
  1
  2
  3

!2005-08-28 Sun

  .class public C2005082800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    istore_0
    iload_0
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-27 Sat

  .class public C2005082700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    istore 5
    iload  5
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-26 Fri

  .class public C2005082600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    istore 0
    iload  0
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-25 Thu

  .class public C2005082500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_m1
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_0
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_1
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_5
  
    invokevirtual java/io/PrintStream/println (I)V
    invokevirtual java/io/PrintStream/println (I)V
    invokevirtual java/io/PrintStream/println (I)V
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  5
  1
  0
  -1

!2005-08-24 Wed

  .class public C2005082400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_m1
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_0
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_1
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_5
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  -1
  0
  1
  5

!2005-08-23 Tue

複数 println を書く方法が分からなかったので、javap -c で逆アセンブルしてみた。
getstatic がそれぞれに必要らしいことが分かった。

jad の場合は、-dis で良いのかな？

  .class public C2005082300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    invokevirtual java/io/PrintStream/println (I)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    invokevirtual java/io/PrintStream/println (F)V
    return
  
  .end method
  .end class
で、
  1
  1.0

!2005-08-22 Mon

  .class public C2005082200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    sipush 1
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

bipush と sipush 何が違うんだったけ？

  .class public C2005082101
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    bipush 256
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  0

文句は言われないけど、bipush は小さな数ということらしい。

!2005-08-21 Sun

  .class public C2005082100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    bipush 1
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-20 Sat

  .class public C2005082000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    dconst_1
    invokevirtual java/io/PrintStream/println (D)V
    return
  
  .end method
  .end class
で、
  1.0

!2005-08-19 Fri

  .class public C2005081900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    dconst_0
    invokevirtual java/io/PrintStream/println (D)V
    return
  
  .end method
  .end class
で、
  0.0

!2005-08-18 Thu

  .class public C2005081800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_2
    invokevirtual java/io/PrintStream/println (F)V
    return
  
  .end method
  .end class
で、
  2.0

!2005-08-17 Wed

  .class public C2005081700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_1
    invokevirtual java/io/PrintStream/println (F)V
    return
  
  .end method
  .end class
で、
  1.0

!2005-08-16 Tue

  .class public C2005081600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    fconst_0
    invokevirtual java/io/PrintStream/println (F)V
    return
  
  .end method
  .end class
で、
  0.0

stack size 2 でも OK。理由不明。

!2005-08-15 Mon

  .class public C2005081500
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    lconst_1
    invokevirtual java/io/PrintStream/println (J)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-14 Sun

  .class public C2005081400
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 3 ; OK
  ; .limit stack 2 ; NG
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    lconst_0
    invokevirtual java/io/PrintStream/println (J)V
    return
  
  .end method
  .end class
で、
  0

!2005-08-13 Sat

  .class public C2005081300
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_5
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  5

!2005-08-12 Fri

  .class public C2005081200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_1
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-11 Thu

  .class public C2005081100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_0
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  0

!2005-08-10 Wed

  .class public C2005081000
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    iconst_m1
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  0

!2005-08-09 Tue

  .class public C2005080900
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 1L
    invokevirtual java/io/PrintStream/println (J)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-08 Mon

  .class public C2005080800
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc2_w 3.14
    invokevirtual java/io/PrintStream/println (D)V
    return
  
  .end method
  .end class
で、
  3.14

!2005-08-07 Sun

  .class public C2005080700
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1.0
    invokevirtual java/io/PrintStream/println (F)V
    return
  
  .end method
  .end class
で、
  1.0

!2005-08-06 Sat

  .class public C2005080600
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  
    getstatic java/lang/System/out Ljava/io/PrintStream;
    ldc 1
    invokevirtual java/io/PrintStream/println (I)V
    return
  
  .end method
  .end class
で、
  1

!2005-08-05 Fri

getstatic ... を削ってみる。

  .class public C2005080500
  ; .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; .limit stack 2
  ; .limit locals 1
  
     ; getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc "Hello World"
     invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
     return
  
  .end method
  .end class
で、
  Exception in thread "main" java.lang.VerifyError: (class: C2005080500, method: main signature: ([Ljava/lang/String;)V) Unable to pop operand off an empty stack

!2005-08-04 Thu

削れそうなものを削ってみる

return を削っちゃえ。

  .class public C2005080400
  ; .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; .limit stack 2
  ; .limit locals 1
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc "Hello World"
     invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
     ; return
  
  .end method
  .end class
で、
  Exception in thread "main" java.lang.VerifyError: (class: C2005080400, method: main signature: ([Ljava/lang/String;)V) Falling off the end of the code

!2005-08-03 Wed

削れそうなものを削ってみる

.super を削っちゃえ。

コメントは、; でも、// でも良いのか？

  .class public C2005080300
  ; .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  ; .limit stack 2
  ; .limit locals 1
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc "Hello World"
     invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
     return
  
  .end method
  .end class
で、
  Hello World

!2005-08-02 Tue

削れそうなものを削ってみる

  .class public C2005080200
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  // .limit stack 2
  // .limit locals 1
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc "Hello World"
     invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
     return
  
  .end method
  .end class
で、
  Hello World

!2005-08-01 Mon

  .class public C2005080100
  .super java/lang/Object
  
  .method public static main ([Ljava/lang/String;)V
  .limit stack 2
  .limit locals 1
  
     getstatic java/lang/System/out Ljava/io/PrintStream;
     ldc "Hello World"
     invokevirtual java/io/PrintStream/println (Ljava/lang/String;)V
     return
  
  .end method
  .end class
で、
  Hello World