diff --git a/ChangeLog b/ChangeLog
index 9a9f5c1..96ceffe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,44 @@
+Tue Sep 16 00:21:10 2008  Minero Aoki  <aamine@loveruby.net>
+
+	* net/loveruby/cflat/asm/Assembler.java: objectify instructions,
+	  directives, comments and labels.
+
+	* net/loveruby/cflat/asm/Label.java: inherits Assembly instead of
+	  AsmEntity.
+
+	* net/loveruby/cflat/asm/Address.java: new method #isAddress.
+
+	* net/loveruby/cflat/asm/ImmediateValue.java: accept Literals.
+
+	* net/loveruby/cflat/asm/AbsoluteAddress.java: new file.
+
+	* net/loveruby/cflat/asm/AsmComment.java: new file.
+
+	* net/loveruby/cflat/asm/Assembly.java: new file.
+
+	* net/loveruby/cflat/asm/Directive.java: new file.
+
+	* net/loveruby/cflat/asm/Reference.java -> DirectAddress.java: new
+	  file.
+
+	* net/loveruby/cflat/asm/SimpleAddress.java, CompositeAddress.java
+	  -> IndirectAddress.java
+
+	* net/loveruby/cflat/asm/Instruction.java: new file.
+
+	* net/loveruby/cflat/asm/IntegerLiteral.java: new file.
+
+	* net/loveruby/cflat/asm/Literal.java: new file.
+
+	* net/loveruby/cflat/asm/Symbol.java: new file.
+
+	* net/loveruby/cflat/compiler/CodeGenerator.java: follow asm
+	  changes.
+
+	* net/loveruby/cflat/ast/UndefinedVariable.java:
+
+	* net/loveruby/cflat/ast/Function.java
+
 Mon Sep 15 21:19:05 2008  Minero Aoki  <aamine@loveruby.net>
 
 	* net/loveruby/cflat/compiler/Compiler.java: link libcbc on making
diff --git a/ToDo b/ToDo
index 478caaa..be67354 100644
--- a/ToDo
+++ b/ToDo
@@ -14,6 +14,7 @@
         * imull $1, %eax => NONE
         * label renaming
         * remove useless jump
+* generate prologue/epilogue after function body.
 * -fPIC (PIC generation)
 * -shared
 * remove all FIXME
@@ -234,3 +235,4 @@
 - -Wa, -Xassembler
 - write install.sh
 - va_list
+- objectify instruction
diff --git a/net/loveruby/cflat/asm/AbsoluteAddress.java b/net/loveruby/cflat/asm/AbsoluteAddress.java
new file mode 100644
index 0000000..762f7b5
--- /dev/null
+++ b/net/loveruby/cflat/asm/AbsoluteAddress.java
@@ -0,0 +1,17 @@
+package net.loveruby.cflat.asm;
+
+public class AbsoluteAddress extends Address {
+    protected Register register;
+
+    public AbsoluteAddress(Register reg) {
+        this.register = reg;
+    }
+
+    public AsmEntity register() {
+        return this.register;
+    }
+
+    public String toString() {
+        return "*" + register.toString();
+    }
+}
diff --git a/net/loveruby/cflat/asm/Address.java b/net/loveruby/cflat/asm/Address.java
index 9a6ce7c..9e7e07c 100644
--- a/net/loveruby/cflat/asm/Address.java
+++ b/net/loveruby/cflat/asm/Address.java
@@ -1,4 +1,7 @@
 package net.loveruby.cflat.asm;
 
 abstract public class Address extends AsmEntity {
+    public boolean isAddress() {
+        return true;
+    }
 }
diff --git a/net/loveruby/cflat/asm/AsmComment.java b/net/loveruby/cflat/asm/AsmComment.java
new file mode 100644
index 0000000..2648e88
--- /dev/null
+++ b/net/loveruby/cflat/asm/AsmComment.java
@@ -0,0 +1,13 @@
+package net.loveruby.cflat.asm;
+
+public class AsmComment extends Assembly {
+    protected String string;
+
+    public AsmComment(String string) {
+        this.string = string;
+    }
+
+    public String toSource() {
+        return "\t# " + string;
+    }
+}
diff --git a/net/loveruby/cflat/asm/AsmEntity.java b/net/loveruby/cflat/asm/AsmEntity.java
index 4717cd5..405db6e 100644
--- a/net/loveruby/cflat/asm/AsmEntity.java
+++ b/net/loveruby/cflat/asm/AsmEntity.java
@@ -2,4 +2,8 @@ package net.loveruby.cflat.asm;
 
 abstract public class AsmEntity {
     abstract public String toString();
+
+    public boolean isAddress() {
+        return false;
+    }
 }
diff --git a/net/loveruby/cflat/asm/Assembler.java b/net/loveruby/cflat/asm/Assembler.java
index b60e884..90ee60a 100644
--- a/net/loveruby/cflat/asm/Assembler.java
+++ b/net/loveruby/cflat/asm/Assembler.java
@@ -4,7 +4,7 @@ import net.loveruby.cflat.utils.*;
 import java.util.*;
 
 public class Assembler {
-    protected List list;
+    protected List list;        // List<Assembly>
     protected Type naturalType;
 
     static public long align(long n, long alignment) {
@@ -20,154 +20,55 @@ public class Assembler {
         StringBuffer buf = new StringBuffer();
         Iterator i = list.iterator();
         while (i.hasNext()) {
-            buf.append((String)i.next());
+            Assembly asm = (Assembly)i.next();
+            buf.append(asm.toSource());
             buf.append("\n");
         }
         return buf.toString();
     }
 
-    protected void op(String op) {
-        list.add("\t" + op);
-    }
-
-    protected void op(String op, AsmEntity ent) {
-        list.add("\t" + op + "\t" + ent.toString());
-    }
-
-    protected void op(String op, AsmEntity ent1, AsmEntity ent2) {
-        list.add("\t" + op + "\t" + ent1.toString() + ", " + ent2.toString());
-    }
-
-    protected void op(String op, String arg) {
-        list.add("\t" + op + "\t" + arg);
-    }
-
-    protected void op(String op, String arg1, String arg2) {
-        list.add("\t" + op + "\t" + arg1 + ", " + arg2);
-    }
-
-    protected void op(String op, String arg1, String arg2, String arg3) {
-        list.add("\t" + op + "\t" + arg1 + ", " + arg2 + ", " + arg3);
-    }
-
     public void comment(String str) {
-        list.add("\t# " + str);
+        list.add(new AsmComment(str));
     }
 
-    public void line(String str) {
-        list.add(str);
-    }
-
-    public void _file(String name) {
-        line("\t.file\t" + TextUtils.dumpString(name));
-    }
-
-    public void _text() {
-        line("\t.text");
-    }
-
-    public void _data() {
-        line("\t.data");
-    }
-
-    public void _section(String name) {
-        line("\t.section\t" + name);
-    }
-
-    public void _globl(String sym) {
-        line(".globl " + sym);
-    }
-
-    public void _local(String sym) {
-        line(".local " + sym);
-    }
-
-    public void _comm(String sym, long size, long alignment) {
-        line("\t.comm\t" + sym + "," + size + "," + alignment);
-    }
-
-    public void _align(long n) {
-        line("\t.align\t" + n);
-    }
-
-    public void _type(String sym, String type) {
-        line("\t.type\t" + sym + ", " + type);
-    }
-
-    public void _size(String sym, long size) {
-        _size(sym, new Long(size).toString());
-    }
-
-    public void _size(String sym, String size) {
-        line("\t.size\t" + sym + ", " + size);
-    }
-
-    public void _byte(long n) {
-        line(".byte\t" + n);
-    }
-
-    public void _value(long n) {
-        line(".value\t" + n);
-    }
-
-    public void _long(long n) {
-        line(".long\t" + n);
-    }
-
-    public void _long(Label label) {
-        line(".long\t" + label);
-    }
-
-    public void _quad(long n) {
-        line(".quad\t" + n);
-    }
-
-    public void _quad(Label label) {
-        line(".quad\t" + label);
-    }
-
-    public void _string(String str) {
-        line("\t.string\t" + TextUtils.dumpString(str));
-    }
-
-    public void label(String label) {
-        line(label + ":");
+    public void label(String sym) {
+        list.add(new Label(sym));
     }
 
     public void label(Label label) {
-        line(label.toString() + ":");
+        list.add(label);
     }
 
-    public void jmp(Label label) {
-        op("jmp", label);
+    protected void directive(String direc) {
+        list.add(new Directive(direc));
     }
 
-    public void jz(Label label) {
-        op("jz", label);
+    protected void insn(String op) {
+        list.add(new Instruction(op));
     }
 
-    public void jnz(Label label) {
-        op("jnz", label);
+    protected void insn(String op, AsmEntity a) {
+        list.add(new Instruction(op, "", a));
     }
 
-    public void je(Label label) {
-        op("je", label);
+    protected void insn(String op, String suffix, AsmEntity a) {
+        list.add(new Instruction(op, suffix, a));
     }
 
-    public void jne(Label label) {
-        op("jne", label);
+    protected void insn(Type t, String op, AsmEntity a) {
+        list.add(new Instruction(op, typeSuffix(t), a));
     }
 
-    protected void typedOp(Type t, String op, AsmEntity a) {
-        op(addSuffix(op, t), a);
+    protected void insn(String op, String suffix, AsmEntity a, AsmEntity b) {
+        list.add(new Instruction(op, suffix, a, b));
     }
 
-    protected void typedOp(Type t, String op, AsmEntity a, AsmEntity b) {
-        op(addSuffix(op, t), a, b);
+    protected void insn(Type t, String op, AsmEntity a, AsmEntity b) {
+        list.add(new Instruction(op, typeSuffix(t), a, b));
     }
 
-    protected String addSuffix(String op, Type t) {
-        return op + typeSuffix(t);
+    protected String typeSuffix(Type t1, Type t2) {
+        return typeSuffix(t1) + typeSuffix(t2);
     }
 
     protected String typeSuffix(Type t) {
@@ -180,82 +81,174 @@ public class Assembler {
         }
     }
 
+    //
+    // directives
+    //
+
+    public void _file(String name) {
+        directive(".file\t" + TextUtils.dumpString(name));
+    }
+
+    public void _text() {
+        directive("\t.text");
+    }
+
+    public void _data() {
+        directive("\t.data");
+    }
+
+    public void _section(String name) {
+        directive("\t.section\t" + name);
+    }
+
+    public void _globl(String sym) {
+        directive(".globl " + sym);
+    }
+
+    public void _local(String sym) {
+        directive(".local " + sym);
+    }
+
+    public void _comm(String sym, long size, long alignment) {
+        directive("\t.comm\t" + sym + "," + size + "," + alignment);
+    }
+
+    public void _align(long n) {
+        directive("\t.align\t" + n);
+    }
+
+    public void _type(String sym, String type) {
+        directive("\t.type\t" + sym + "," + type);
+    }
+
+    public void _size(String sym, long size) {
+        _size(sym, new Long(size).toString());
+    }
+
+    public void _size(String sym, String size) {
+        directive("\t.size\t" + sym + "," + size);
+    }
+
+    public void _byte(long n) {
+        directive(".byte\t" + n);
+    }
+
+    public void _value(long n) {
+        directive(".value\t" + n);
+    }
+
+    public void _long(long n) {
+        directive(".long\t" + n);
+    }
+
+    public void _long(Label sym) {
+        directive(".long\t" + sym.toString());
+    }
+
+    public void _quad(long n) {
+        directive(".quad\t" + n);
+    }
+
+    public void _quad(Label sym) {
+        directive(".quad\t" + sym.toString());
+    }
+
+    public void _string(String str) {
+        directive("\t.string\t" + TextUtils.dumpString(str));
+    }
+
+    //
+    // Instructions
+    //
+
+    public void jmp(Label label) {
+        insn("jmp", new Symbol(label));
+    }
+
+    public void jz(Label label) {
+        insn("jz", new Symbol(label));
+    }
+
+    public void jnz(Label label) {
+        insn("jnz", new Symbol(label));
+    }
+
+    public void je(Label label) {
+        insn("je", new Symbol(label));
+    }
+
+    public void jne(Label label) {
+        insn("jne", new Symbol(label));
+    }
+
     public void cmp(Type t, Register a, Register b) {
-        typedOp(t, "cmp", a, b);
+        insn(t, "cmp", a, b);
     }
 
     public void sete(Register reg) {
-        op("sete", reg);
+        insn("sete", reg);
     }
 
     public void setne(Register reg) {
-        op("setne", reg);
+        insn("setne", reg);
     }
 
     public void seta(Register reg) {
-        op("seta", reg);
+        insn("seta", reg);
     }
 
     public void setae(Register reg) {
-        op("setae", reg);
+        insn("setae", reg);
     }
 
     public void setb(Register reg) {
-        op("setb", reg);
+        insn("setb", reg);
     }
 
     public void setbe(Register reg) {
-        op("setbe", reg);
+        insn("setbe", reg);
     }
 
     public void setg(Register reg) {
-        op("setg", reg);
+        insn("setg", reg);
     }
 
     public void setge(Register reg) {
-        op("setge", reg);
+        insn("setge", reg);
     }
 
     public void setl(Register reg) {
-        op("setl", reg);
+        insn("setl", reg);
     }
 
     public void setle(Register reg) {
-        op("setle", reg);
+        insn("setle", reg);
     }
 
     public void test(Type type, Register a, Register b) {
-        typedOp(type, "test", a, b);
+        insn(type, "test", a, b);
     }
 
     public void push(Register reg) {
-        push(naturalType, reg);
-    }
-
-    public void push(Type t, Register reg) {
-        typedOp(t, "push", reg);
+        insn("push", typeSuffix(naturalType), reg);
     }
 
     public void pop(Register reg) {
-        pop(naturalType, reg);
-    }
-
-    public void pop(Type t, Register reg) {
-        op("popl", reg);
+        insn("pop", typeSuffix(naturalType), reg);
     }
 
     // call function by relative address
     public void call(String sym) {
-        op("call", sym);
+        insn("call", new Symbol(new Label(sym)));
     }
 
     // call function by absolute address
     public void callAbsolute(Register reg) {
-        op("call", "*" + reg.toString());
+        insn("call", new AbsoluteAddress(reg));
     }
 
     public void ret() {
-        op("ret");
+        insn("ret");
     }
 
     public void mov(AsmEntity src, AsmEntity dest) {
@@ -263,35 +256,35 @@ public class Assembler {
     }
 
     public void mov(Type type, AsmEntity src, AsmEntity dest) {
-        typedOp(type, "mov", src, dest);
+        insn(type, "mov", src, dest);
     }
 
-    public void movsx(Type from, Type to, AsmEntity src, AsmEntity dest) {
-        op("movs" + typeSuffix(from) + typeSuffix(to), src, dest);
+    public void movsx(Type t1, Type t2, AsmEntity src, AsmEntity dest) {
+        insn("movs", typeSuffix(t1, t2), src, dest);
     }
 
     public void movsbl(AsmEntity src, AsmEntity dest) {
-        op("movsbl", src, dest);
+        insn("movs", "bl", src, dest);
     }
 
     public void movswl(AsmEntity src, AsmEntity dest) {
-        op("movswl", src, dest);
+        insn("movs", "wl", src, dest);
     }
 
-    public void movzx(Type from, Type to, AsmEntity src, AsmEntity dest) {
-        op("movz" + typeSuffix(from) + typeSuffix(to), src, dest);
+    public void movzx(Type t1, Type t2, AsmEntity src, AsmEntity dest) {
+        insn("movz", typeSuffix(t1, t2), src, dest);
     }
 
-    public void movzb(Type type, AsmEntity src, AsmEntity dest) {
-        typedOp(type, "movzb", src, dest);
+    public void movzb(Type t, AsmEntity src, AsmEntity dest) {
+        insn("movz", "b" + typeSuffix(t), src, dest);
     }
 
     public void movzbl(AsmEntity src, AsmEntity dest) {
-        op("movzbl", src, dest);
+        insn("movz", "bl", src, dest);
     }
 
     public void movzwl(AsmEntity src, AsmEntity dest) {
-        op("movzwl", src, dest);
+        insn("movz", "wl", src, dest);
     }
 
     public void lea(AsmEntity src, AsmEntity dest) {
@@ -299,19 +292,19 @@ public class Assembler {
     }
 
     public void lea(Type type, AsmEntity src, AsmEntity dest) {
-        typedOp(type, "lea", src, dest);
+        insn(type, "lea", src, dest);
     }
 
     public void neg(Type type, Register reg) {
-        typedOp(type, "neg", reg);
+        insn(type, "neg", reg);
     }
 
     public void inc(Type type, AsmEntity reg) {
-        typedOp(type, "inc", reg);
+        insn(type, "inc", reg);
     }
 
     public void dec(Type type, AsmEntity reg) {
-        typedOp(type, "dec", reg);
+        insn(type, "dec", reg);
     }
 
     public void add(AsmEntity diff, AsmEntity base) {
@@ -319,7 +312,7 @@ public class Assembler {
     }
 
     public void add(Type type, AsmEntity diff, AsmEntity base) {
-        typedOp(type, "add", diff, base);
+        insn(type, "add", diff, base);
     }
 
     public void sub(AsmEntity diff, AsmEntity base) {
@@ -327,7 +320,7 @@ public class Assembler {
     }
 
     public void sub(Type type, AsmEntity diff, AsmEntity base) {
-        typedOp(type, "sub", diff, base);
+        insn(type, "sub", diff, base);
     }
 
     public void imul(AsmEntity m, Register base) {
@@ -335,46 +328,46 @@ public class Assembler {
     }
 
     public void imul(Type type, AsmEntity m, Register base) {
-        typedOp(type, "imul", m, base);
+        insn(type, "imul", m, base);
     }
 
     public void cltd() {
-        op("cltd");
+        insn("cltd");
     }
 
     public void div(Type type, Register base) {
-        typedOp(type, "div", base);
+        insn(type, "div", base);
     }
 
     public void idiv(Type type, Register base) {
-        typedOp(type, "idiv", base);
+        insn(type, "idiv", base);
     }
 
     public void not(Type type, Register reg) {
-        typedOp(type, "not", reg);
+        insn(type, "not", reg);
     }
 
     public void and(Type type, Register bits, Register base) {
-        typedOp(type, "and", bits, base);
+        insn(type, "and", bits, base);
     }
 
     public void or(Type type, Register bits, Register base) {
-        typedOp(type, "or", bits, base);
+        insn(type, "or", bits, base);
     }
 
     public void xor(Type type, Register bits, Register base) {
-        typedOp(type, "xor", bits, base);
+        insn(type, "xor", bits, base);
     }
 
     public void sar(Type type, Register bits, Register base) {
-        typedOp(type, "sar", bits, base);
+        insn(type, "sar", bits, base);
     }
 
     public void sal(Type type, Register bits, Register base) {
-        typedOp(type, "sal", bits, base);
+        insn(type, "sal", bits, base);
     }
 
     public void shr(Type type, Register bits, Register base) {
-        typedOp(type, "shr", bits, base);
+        insn(type, "shr", bits, base);
     }
 }
diff --git a/net/loveruby/cflat/asm/Assembly.java b/net/loveruby/cflat/asm/Assembly.java
new file mode 100644
index 0000000..23d9450
--- /dev/null
+++ b/net/loveruby/cflat/asm/Assembly.java
@@ -0,0 +1,13 @@
+package net.loveruby.cflat.asm;
+
+abstract public class Assembly {
+    abstract public String toSource();
+
+    public boolean isInstruction() {
+        return false;
+    }
+
+    public boolean isLabel() {
+        return false;
+    }
+}
diff --git a/net/loveruby/cflat/asm/CompositeAddress.java b/net/loveruby/cflat/asm/CompositeAddress.java
deleted file mode 100644
index b373b8b..0000000
--- a/net/loveruby/cflat/asm/CompositeAddress.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package net.loveruby.cflat.asm;
-
-public class CompositeAddress extends Address {
-    long offset;
-    Register base;
-
-    public CompositeAddress(long off, Register reg) {
-        offset = off;
-        base = reg;
-    }
-
-    public long offset() {
-        return offset;
-    }
-
-    public Register base() {
-        return base;
-    }
-
-    public String toString() {
-        return "" + offset + "(" + base.toString() + ")";
-    }
-}
diff --git a/net/loveruby/cflat/asm/DirectAddress.java b/net/loveruby/cflat/asm/DirectAddress.java
new file mode 100644
index 0000000..4d9c437
--- /dev/null
+++ b/net/loveruby/cflat/asm/DirectAddress.java
@@ -0,0 +1,21 @@
+package net.loveruby.cflat.asm;
+
+public class DirectAddress extends Address {
+    protected Literal value;
+
+    public DirectAddress(Label label) {
+        this.value = new Symbol(label);
+    }
+
+    public DirectAddress(IntegerLiteral n) {
+        this.value = n;
+    }
+
+    public Literal value() {
+        return this.value;
+    }
+
+    public String toString() {
+        return this.value.toString();
+    }
+}
diff --git a/net/loveruby/cflat/asm/Directive.java b/net/loveruby/cflat/asm/Directive.java
new file mode 100644
index 0000000..2c8d5b1
--- /dev/null
+++ b/net/loveruby/cflat/asm/Directive.java
@@ -0,0 +1,13 @@
+package net.loveruby.cflat.asm;
+
+public class Directive extends Assembly {
+    protected String content;
+
+    public Directive(String content) {
+        this.content = content;
+    }
+
+    public String toSource() {
+        return this.content;
+    }
+}
diff --git a/net/loveruby/cflat/asm/ImmediateValue.java b/net/loveruby/cflat/asm/ImmediateValue.java
index c4a55c5..58e105d 100644
--- a/net/loveruby/cflat/asm/ImmediateValue.java
+++ b/net/loveruby/cflat/asm/ImmediateValue.java
@@ -1,17 +1,25 @@
 package net.loveruby.cflat.asm;
 
 public class ImmediateValue extends AsmEntity {
-    long value;
+    protected AsmEntity entity;
 
     public ImmediateValue(long n) {
-        value = n;
+        this(new IntegerLiteral(n));
     }
 
-    public long value() {
-        return value;
+    public ImmediateValue(Label label) {
+        this(new Symbol(label));
+    }
+
+    public ImmediateValue(AsmEntity entity) {
+        this.entity = entity;
+    }
+
+    public AsmEntity entity() {
+        return this.entity;
     }
 
     public String toString() {
-        return "$" + value;
+        return "$" + entity.toString();
     }
 }
diff --git a/net/loveruby/cflat/asm/IndirectAddress.java b/net/loveruby/cflat/asm/IndirectAddress.java
new file mode 100644
index 0000000..8d4f2c9
--- /dev/null
+++ b/net/loveruby/cflat/asm/IndirectAddress.java
@@ -0,0 +1,27 @@
+package net.loveruby.cflat.asm;
+
+public class IndirectAddress extends Address {
+    protected long offset;
+    protected Register base;
+
+    public IndirectAddress(Register base) {
+        this(0, base);
+    }
+
+    public IndirectAddress(long offset, Register base) {
+        this.offset = offset;
+        this.base = base;
+    }
+
+    public long offset() {
+        return offset;
+    }
+
+    public Register base() {
+        return base;
+    }
+
+    public String toString() {
+        return (offset == 0 ? "" : "" + offset) + "(" + base.toString() + ")";
+    }
+}
diff --git a/net/loveruby/cflat/asm/Instruction.java b/net/loveruby/cflat/asm/Instruction.java
new file mode 100644
index 0000000..cd4a187
--- /dev/null
+++ b/net/loveruby/cflat/asm/Instruction.java
@@ -0,0 +1,62 @@
+package net.loveruby.cflat.asm;
+import net.loveruby.cflat.type.Type;
+
+public class Instruction extends Assembly {
+    protected String mnemonic;
+    protected String suffix;
+    protected AsmEntity[] operands;
+
+    public Instruction(String mnemonic) {
+        this(mnemonic, "", new AsmEntity[0]);
+    }
+
+    public Instruction(String mnemonic, String suffix, AsmEntity a1) {
+        this(mnemonic, suffix, new AsmEntity[] { a1 });
+    }
+
+    public Instruction(String mnemonic, String suffix,
+                       AsmEntity a1, AsmEntity a2) {
+        this(mnemonic, suffix, new AsmEntity[] { a1, a2 });
+    }
+
+    public Instruction(String mnemonic, String suffix, AsmEntity[] operands) {
+        this.mnemonic = mnemonic;
+        this.suffix = suffix;
+        this.operands = operands;
+    }
+
+    public boolean isInstruction() {
+        return true;
+    }
+
+    public String mnemonic() {
+        return this.mnemonic;
+    }
+
+    public int numOperands() {
+        return this.operands.length;
+    }
+
+    public AsmEntity operand1() {
+        return this.operands[0];
+    }
+
+    public AsmEntity operand2() {
+        return this.operands[1];
+    }
+
+    public String toSource() {
+        StringBuffer buf = new StringBuffer();
+        buf.append(mnemonic + suffix);
+        String sep = "\t";
+        for (int i = 0; i < operands.length; i++) {
+            buf.append(sep); sep = ", ";
+            buf.append(operands[i]);
+        }
+        return buf.toString();
+    }
+
+    public String toString() {
+        return "#<Insn " + mnemonic + ">";
+    }
+}
diff --git a/net/loveruby/cflat/asm/IntegerLiteral.java b/net/loveruby/cflat/asm/IntegerLiteral.java
new file mode 100644
index 0000000..5c0650a
--- /dev/null
+++ b/net/loveruby/cflat/asm/IntegerLiteral.java
@@ -0,0 +1,17 @@
+package net.loveruby.cflat.asm;
+
+public class IntegerLiteral extends Literal {
+    protected long value;
+
+    public IntegerLiteral(long n) {
+        this.value = n;
+    }
+
+    public long value() {
+        return this.value;
+    }
+
+    public String toString() {
+        return new Long(value).toString();
+    }
+}
diff --git a/net/loveruby/cflat/asm/Label.java b/net/loveruby/cflat/asm/Label.java
index 376524c..4488b57 100644
--- a/net/loveruby/cflat/asm/Label.java
+++ b/net/loveruby/cflat/asm/Label.java
@@ -1,8 +1,8 @@
 package net.loveruby.cflat.asm;
 
-public class Label extends AsmEntity {
-    long seq;
-    String name;
+public class Label extends Assembly {
+    protected long seq;
+    protected String name;
 
     public Label(String n) {
         seq = -1;
@@ -22,6 +22,10 @@ public class Label extends AsmEntity {
         return name;
     }
 
+    public String toSource() {
+        return name + ":";
+    }
+
     public String toString() {
         return name;
     }
diff --git a/net/loveruby/cflat/asm/Literal.java b/net/loveruby/cflat/asm/Literal.java
new file mode 100644
index 0000000..a0cb381
--- /dev/null
+++ b/net/loveruby/cflat/asm/Literal.java
@@ -0,0 +1,4 @@
+package net.loveruby.cflat.asm;
+
+abstract public class Literal extends AsmEntity {
+}
diff --git a/net/loveruby/cflat/asm/Reference.java b/net/loveruby/cflat/asm/Reference.java
deleted file mode 100644
index 2c3c0b1..0000000
--- a/net/loveruby/cflat/asm/Reference.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package net.loveruby.cflat.asm;
-
-public class Reference extends Address {
-    protected Label label;
-
-    public Reference(String sym) {
-        this(new Label(sym));
-    }
-
-    public Reference(Label label) {
-        this.label = label;
-    }
-
-    public String toString() {
-        return "$" + label.toString();
-    }
-}
diff --git a/net/loveruby/cflat/asm/SimpleAddress.java b/net/loveruby/cflat/asm/SimpleAddress.java
deleted file mode 100644
index 28358cd..0000000
--- a/net/loveruby/cflat/asm/SimpleAddress.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package net.loveruby.cflat.asm;
-
-public class SimpleAddress extends Address {
-    Register base;
-
-    public SimpleAddress(Register reg) {
-        base = reg;
-    }
-
-    public Register base() {
-        return base;
-    }
-
-    public String toString() {
-        return "(" + base.toString() + ")";
-    }
-}
diff --git a/net/loveruby/cflat/asm/Symbol.java b/net/loveruby/cflat/asm/Symbol.java
new file mode 100644
index 0000000..27597da
--- /dev/null
+++ b/net/loveruby/cflat/asm/Symbol.java
@@ -0,0 +1,17 @@
+package net.loveruby.cflat.asm;
+
+public class Symbol extends Literal {
+    protected Label label;
+
+    public Symbol(Label label) {
+        this.label = label;
+    }
+
+    public String symbol() {
+        return label.name();
+    }
+
+    public String toString() {
+        return symbol();
+    }
+}
diff --git a/net/loveruby/cflat/ast/Function.java b/net/loveruby/cflat/ast/Function.java
index 6f0116c..9f93037 100644
--- a/net/loveruby/cflat/ast/Function.java
+++ b/net/loveruby/cflat/ast/Function.java
@@ -26,6 +26,6 @@ abstract public class Function extends Entity {
     }
 
     public AsmEntity address() {
-        return new Reference(name());
+        return new DirectAddress(new Label(name()));
     }
 }
diff --git a/net/loveruby/cflat/ast/UndefinedVariable.java b/net/loveruby/cflat/ast/UndefinedVariable.java
index c883aeb..f9e72b5 100644
--- a/net/loveruby/cflat/ast/UndefinedVariable.java
+++ b/net/loveruby/cflat/ast/UndefinedVariable.java
@@ -20,7 +20,7 @@ public class UndefinedVariable extends Variable {
     }
 
     public AsmEntity address() {
-        return new Label(symbol());
+        return new DirectAddress(new Label(symbol()));
     }
 
     protected void _dump(Dumper d) {
diff --git a/net/loveruby/cflat/compiler/CodeGenerator.java b/net/loveruby/cflat/compiler/CodeGenerator.java
index 11231b3..098e513 100644
--- a/net/loveruby/cflat/compiler/CodeGenerator.java
+++ b/net/loveruby/cflat/compiler/CodeGenerator.java
@@ -82,13 +82,13 @@ public class CodeGenerator extends Visitor implements ASTLHSVisitor {
     /** Linux/IA-32 dependent */
     // FIXME: PIC
     protected AsmEntity globalVariableAddress(String sym) {
-        return new Label(csymbol(sym));
+        return new Symbol(new Label(csymbol(sym)));
     }
 
     /** Linux/IA-32 dependent */
     // FIXME: PIC
     protected AsmEntity commonSymbolAddress(String sym) {
-        return new Label(csymbol(sym));
+        return new Symbol(new Label(csymbol(sym)));
     }
 
     /** Generates static variable entries */
@@ -866,20 +866,20 @@ public class CodeGenerator extends Visitor implements ASTLHSVisitor {
         return new Register(name);
     }
 
-    protected SimpleAddress mem(Register reg) {
-        return new SimpleAddress(reg);
+    protected IndirectAddress mem(Register reg) {
+        return new IndirectAddress(reg);
     }
 
-    protected CompositeAddress mem(long offset, Register reg) {
-        return new CompositeAddress(offset, reg);
+    protected IndirectAddress mem(long offset, Register reg) {
+        return new IndirectAddress(offset, reg);
     }
 
     protected ImmediateValue imm(long n) {
         return new ImmediateValue(n);
     }
 
-    protected Reference imm(Label label) {
-        return new Reference(label);
+    protected ImmediateValue imm(Label label) {
+        return new ImmediateValue(label);
     }
 
     protected void load(Type type, AsmEntity addr, Register reg) {
@@ -909,7 +909,6 @@ public class CodeGenerator extends Visitor implements ASTLHSVisitor {
     }
 
     public void comment(String str) { as.comment(str); }
-    public void line(String str) { as.line(str); }
     public void _file(String name) { as._file(name); }
     public void _text() { as._text(); }
     public void _data() { as._data(); }