diff --git a/build.xml b/build.xml
index ba1e4f2e..9eb83caf 100644
--- a/build.xml
+++ b/build.xml
@@ -3,7 +3,7 @@
 
 <target name="prepare-build">
     <property file="properties"/>
-    <property name="asm" value="${basedir}/asm-3.1-p1r.jar"/>
+    <property name="asm" value="${basedir}/asm-5.0.3rr.jar"/>
     <property name="build"  value="${basedir}/.build"/>
     <property name="jardir" value="${basedir}"/>
     <property name="docdir" value="${build}/doc"/>
@@ -11,9 +11,9 @@
 </target>
 
 <target name="fetch" depends="prepare-build" unless="has.asm">
-    <property name="asmt" value="${build}/asm-3.1-p1.jar"/>
+    <property name="asmt" value="${build}/asm-5.0.3.jar"/>
     <mkdir dir="${build}/util"/>
-    <get src="http://dot.planet.ee/yeti/asm-3.1-p1.jar"
+    <get src="http://dot.planet.ee/yeti/asm-5.0.3.jar"
          dest="${asmt}" verbose="true"/>
     <javac destdir="${build}/util" srcdir="${basedir}/util"
            includes="Rename.java" encoding="UTF-8"
diff --git a/c/ClassFinder.java b/c/ClassFinder.java
index 5b86f21a..7130f7be 100644
--- a/c/ClassFinder.java
+++ b/c/ClassFinder.java
@@ -206,6 +206,9 @@ JavaTypeReader readClass(String className) {
                     ClassReader.SKIP_CODE | ClassReader.SKIP_FRAMES);
         } catch (IOException ex) {
             return null;
+        } catch (Exception ex) {
+            throw new RuntimeException("Internal error reading class " +
+                        className + ": " + ex.getMessage(), ex);
         }
         return t;
     }
diff --git a/c/JavaType.java b/c/JavaType.java
index a48db8d4..e2c2a79b 100644
--- a/c/JavaType.java
+++ b/c/JavaType.java
@@ -42,7 +42,7 @@ public JavaClassNotFoundException(String what) {
     }
 }
 
-class JavaTypeReader implements ClassVisitor, Opcodes {
+class JavaTypeReader extends ClassVisitor implements Opcodes {
     Map vars = new HashMap();
     Map fields = new HashMap();
     Map staticFields = new HashMap();
@@ -54,6 +54,10 @@ class JavaTypeReader implements ClassVisitor, Opcodes {
     String[] interfaces;
     int access;
 
+    JavaTypeReader() {
+        super(ASM5);
+    }
+
     public void visit(int version, int access, String name, String signature,
                       String superName, String[] interfaces) {
         if (superName != null)
diff --git a/c/TypeAttr.java b/c/TypeAttr.java
index d0f8a919..481f61f3 100644
--- a/c/TypeAttr.java
+++ b/c/TypeAttr.java
@@ -426,10 +426,14 @@ Tag yetiType() {
     }
 }
 
-class YetiTypeVisitor implements ClassVisitor {
+class YetiTypeVisitor extends ClassVisitor {
     TypeAttr typeAttr;
     private boolean deprecated;
 
+    YetiTypeVisitor() {
+        super(Opcodes.ASM5);
+    }
+
     public void visit(int version, int access, String name, String signature,
                       String superName, String[] interfaces) {
         deprecated = (access & Opcodes.ACC_DEPRECATED) != 0;
diff --git a/c/YetiCode.java b/c/YetiCode.java
index 78801ed8..e96523af 100644
--- a/c/YetiCode.java
+++ b/c/YetiCode.java
@@ -226,7 +226,7 @@ void createInit(int mod, String parent) {
         MethodVisitor m = cw.visitMethod(mod, "<init>", "()V", null, null);
         // super()
         m.visitVarInsn(ALOAD, 0);
-        m.visitMethodInsn(INVOKESPECIAL, parent, "<init>", "()V");
+        m.visitMethodInsn(INVOKESPECIAL, parent, "<init>", "()V", false);
         m.visitInsn(RETURN);
         m.visitMaxs(0, 0);
         m.visitEnd();
@@ -316,7 +316,7 @@ void captureCast(String type) {
 
     void visitInit(String type, String descr) {
         insn(-2);
-        m.visitMethodInsn(INVOKESPECIAL, type, "<init>", descr);
+        m.visitMethodInsn(INVOKESPECIAL, type, "<init>", descr, false);
         lastType = type;
     }
 
@@ -340,7 +340,7 @@ void fieldInsn(int opcode, String owner, String name, String desc) {
 
     void methodInsn(int opcode, String owner, String name, String desc) {
         insn(-1);
-        m.visitMethodInsn(opcode, owner, name, desc);
+        m.visitMethodInsn(opcode, owner, name, desc, opcode == INVOKEINTERFACE);
     }
 
     void visitApply(Code arg, int line) {
@@ -348,7 +348,7 @@ void visitApply(Code arg, int line) {
         insn(-1);
         visitLine(line);
         m.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun",
-                "apply", "(Ljava/lang/Object;)Ljava/lang/Object;");
+                "apply", "(Ljava/lang/Object;)Ljava/lang/Object;", false);
     }
 
     void jumpInsn(int opcode, Label label) {
diff --git a/util/Rename.java b/util/Rename.java
index 9b619b43..ab9fae5a 100644
--- a/util/Rename.java
+++ b/util/Rename.java
@@ -59,7 +59,7 @@ public static void main(String[] args) throws Exception {
         JarFile in = new JarFile(args[0]);
         JarOutputStream out =
             new JarOutputStream(new FileOutputStream(args[1]));
-        byte[] buf = new byte[65536];
+        byte[] buf = new byte[0x20000];
         for (Enumeration e = in.entries(); e.hasMoreElements();) {
             ZipEntry z = (ZipEntry) e.nextElement();
             if (z.isDirectory())
diff --git a/util/SpecialLib.java b/util/SpecialLib.java
index a3a7d840..6cc1b196 100644
--- a/util/SpecialLib.java
+++ b/util/SpecialLib.java
@@ -33,9 +33,9 @@
 import java.io.*;
 import yeti.renamed.asm3.*;
 
-class LListAdapter extends ClassAdapter implements Opcodes {
+class LListAdapter extends ClassVisitor implements Opcodes {
     LListAdapter(ClassVisitor cv) {
-        super(cv);
+        super(ASM5, cv);
     }
 
     public MethodVisitor visitMethod(int access, String name, String desc,
@@ -58,7 +58,7 @@ public void visitEnd() {
         mv.visitLabel(retry);
         mv.visitIincInsn(0, 1);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "next", "()Lyeti/lang/AIter;");
+                           "next", "()Lyeti/lang/AIter;", false);
         mv.visitInsn(DUP);
         mv.visitJumpInsn(IFNONNULL, retry);
         mv.visitLabel(end);
@@ -79,12 +79,13 @@ public void visitEnd() {
         mv.visitLabel(retry = new Label());
         mv.visitInsn(DUP2); // fun iter fun iter
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "first", "()Ljava/lang/Object;");
+                           "first", "()Ljava/lang/Object;", false);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun",
-                           "apply", "(Ljava/lang/Object;)Ljava/lang/Object;");
+                           "apply", "(Ljava/lang/Object;)Ljava/lang/Object;",
+                           false);
         mv.visitInsn(POP);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "next", "()Lyeti/lang/AIter;");
+                           "next", "()Lyeti/lang/AIter;", false);
         mv.visitInsn(DUP);
         mv.visitJumpInsn(IFNONNULL, retry);
         mv.visitLabel(end);
@@ -105,12 +106,12 @@ public void visitEnd() {
         mv.visitInsn(SWAP);
         mv.visitVarInsn(ALOAD, 0);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "first", "()Ljava/lang/Object;");
+                           "first", "()Ljava/lang/Object;", false);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun", "apply",
-            "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;");
+            "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;", false);
         mv.visitVarInsn(ALOAD, 0); 
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "next", "()Lyeti/lang/AIter;");
+                           "next", "()Lyeti/lang/AIter;", false);
         mv.visitInsn(DUP);
         mv.visitVarInsn(ASTORE, 0);
         mv.visitJumpInsn(IFNONNULL, retry);
@@ -129,20 +130,20 @@ public void visitEnd() {
         mv.visitTypeInsn(NEW, "yeti/lang/MList");
         mv.visitInsn(DUP);
         mv.visitMethodInsn(INVOKESPECIAL, "yeti/lang/MList",
-                           "<init>", "()V");
+                           "<init>", "()V", false);
         mv.visitVarInsn(ASTORE, 0);
         mv.visitLabel(retry = new Label());
         mv.visitInsn(DUP2); // fun iter fun iter
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "first", "()Ljava/lang/Object;"); // i -> v
-        mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun", // f v -> v'
-                           "apply", "(Ljava/lang/Object;)Ljava/lang/Object;");
+                           "first", "()Ljava/lang/Object;", false); // i -> v
+        mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun", "apply", // f v -> v'
+                           "(Ljava/lang/Object;)Ljava/lang/Object;", false);
         mv.visitVarInsn(ALOAD, 0);
         mv.visitInsn(SWAP);
-        mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/MList",
-                           "add", "(Ljava/lang/Object;)V"); // l v' -> ()
-        mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter",
-                           "next", "()Lyeti/lang/AIter;"); // i -> i'
+        mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/MList", "add",
+                           "(Ljava/lang/Object;)V", false); // l v' -> ()
+        mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AIter", "next",
+                           "()Lyeti/lang/AIter;", false); // i -> i'
         mv.visitInsn(DUP);
         mv.visitJumpInsn(IFNONNULL, retry);
         mv.visitVarInsn(ALOAD, 0);
@@ -160,7 +161,7 @@ public void visitEnd() {
         mv.visitInsn(ACONST_NULL);
         mv.visitVarInsn(ASTORE, 0);
         mv.visitMethodInsn(INVOKESPECIAL, "yeti/lang/MList",
-                           "<init>", "(Lyeti/lang/AIter;)V");
+                           "<init>", "(Lyeti/lang/AIter;)V", false);
         mv.visitInsn(ARETURN);
         mv.visitMaxs(0, 0);
         mv.visitEnd();
@@ -176,7 +177,7 @@ public void visitEnd() {
         mv.visitVarInsn(ILOAD, 1);
         mv.visitJumpInsn(IFLE, drop);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/AList",
-                           "rest", "()Lyeti/lang/AList;"); // i -> i'
+                           "rest", "()Lyeti/lang/AList;", false); // i -> i'
         mv.visitIincInsn(1, -1);
         mv.visitInsn(DUP);
         mv.visitJumpInsn(IFNONNULL, retry);
@@ -186,8 +187,8 @@ public void visitEnd() {
         mv.visitVarInsn(ILOAD, 2);
         mv.visitJumpInsn(IFLT, end = new Label());
         mv.visitVarInsn(ILOAD, 2);
-        mv.visitMethodInsn(INVOKESTATIC, "yeti/lang/TakeList",
-                           "take", "(Lyeti/lang/AIter;I)Lyeti/lang/AList;");
+        mv.visitMethodInsn(INVOKESTATIC, "yeti/lang/TakeList", "take",
+                           "(Lyeti/lang/AIter;I)Lyeti/lang/AList;", false);
         mv.visitLabel(end);
         mv.visitInsn(ARETURN);
         mv.visitMaxs(0, 0);
@@ -232,7 +233,8 @@ void fun2_() throws Exception {
                         "(Lyeti/lang/Fun2;Ljava/lang/Object;)V", null, null);
         mv.visitCode();
         mv.visitVarInsn(ALOAD, 0);
-        mv.visitMethodInsn(INVOKESPECIAL, "yeti/lang/Fun", "<init>", "()V");
+        mv.visitMethodInsn(INVOKESPECIAL, "yeti/lang/Fun",
+                           "<init>", "()V", false);
         mv.visitVarInsn(ALOAD, 0);
         mv.visitVarInsn(ALOAD, 1);
         mv.visitFieldInsn(PUTFIELD, "yeti/lang/Fun2_",
@@ -259,7 +261,7 @@ void fun2_() throws Exception {
         mv.visitInsn(ACONST_NULL);
         mv.visitVarInsn(ASTORE, 1);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun2", "apply",
-            "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;");
+            "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;", false);
         mv.visitInsn(ARETURN);
         mv.visitMaxs(0, 0);
         mv.visitEnd();
@@ -278,7 +280,8 @@ void compose() throws Exception {
             "(Ljava/lang/Object;Ljava/lang/Object;)V", null, null);
         mv.visitCode();
         mv.visitVarInsn(ALOAD, 0);
-        mv.visitMethodInsn(INVOKESPECIAL, "yeti/lang/Fun", "<init>", "()V");
+        mv.visitMethodInsn(INVOKESPECIAL, "yeti/lang/Fun",
+                           "<init>", "()V", false);
         mv.visitVarInsn(ALOAD, 0);
         mv.visitVarInsn(ALOAD, 1);
         mv.visitTypeInsn(CHECKCAST, "yeti/lang/Fun");
@@ -306,9 +309,9 @@ void compose() throws Exception {
         mv.visitInsn(ACONST_NULL);
         mv.visitVarInsn(ASTORE, 1);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun", "apply",
-            "(Ljava/lang/Object;)Ljava/lang/Object;");
+            "(Ljava/lang/Object;)Ljava/lang/Object;", false);
         mv.visitMethodInsn(INVOKEVIRTUAL, "yeti/lang/Fun", "apply",
-            "(Ljava/lang/Object;)Ljava/lang/Object;");
+            "(Ljava/lang/Object;)Ljava/lang/Object;", false);
         mv.visitInsn(ARETURN);
         mv.visitMaxs(0, 0);
         mv.visitEnd();