diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TObject.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TObject.java
index 3fb6b2e9a..376c007ea 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TObject.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TObject.java
@@ -127,7 +127,7 @@ public class TObject {
                         o.monitor.enteringThreads.remove().run();
                     }
                 }
-            });
+            }, false);
         } else {
             o.isEmptyMonitor();
         }
@@ -203,7 +203,7 @@ public class TObject {
         while (!listeners.isEmpty()) {
             NotifyListener listener = listeners.remove();
             if (!listener.expired()) {
-                Platform.startThread(listener);
+                Platform.startThread(listener, false);
                 break;
             }
         }
@@ -219,7 +219,7 @@ public class TObject {
         while (!listeners.isEmpty()) {
             NotifyListener listener = listeners.remove();
             if (!listener.expired()) {
-                Platform.startThread(listener);
+                Platform.startThread(listener, false);
             }
         }
     }
@@ -279,7 +279,7 @@ public class TObject {
         @Override
         public void onTimer() {
             if (!expired()) {
-                Platform.startThread(this);
+                Platform.startThread(this, false);
             }
         }
 
diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TThread.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TThread.java
index a635bc045..416a5be0d 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TThread.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/lang/TThread.java
@@ -71,7 +71,7 @@ public class TThread extends TObject implements TRunnable {
                     setCurrentThread(mainThread);
                 }
             }
-        });
+        }, true);
     }
 
     static void setCurrentThread(TThread thread) {
@@ -116,7 +116,7 @@ public class TThread extends TObject implements TRunnable {
                 setCurrentThread(thread);
                 callback.complete(null);
             }
-        });
+        }, false);
     }
 
     private static void yieldImpl() {
diff --git a/teavm-core/src/main/java/org/teavm/cache/AstIO.java b/teavm-core/src/main/java/org/teavm/cache/AstIO.java
index b1ead2777..78264c5ba 100644
--- a/teavm-core/src/main/java/org/teavm/cache/AstIO.java
+++ b/teavm-core/src/main/java/org/teavm/cache/AstIO.java
@@ -315,10 +315,18 @@ public class AstIO {
         }
 
         @Override
-        public void visit(MonitorEnterStatement statement) {
+        public void visit(SaveStatement statement) {
             try {
                 output.writeByte(18);
-                output.writeShort(statement.getAsyncTarget() != null ? 0 : statement.getAsyncTarget());
+            } catch (IOException e) {
+                throw new IOExceptionWrapper(e);
+            }
+        }
+
+        @Override
+        public void visit(MonitorEnterStatement statement) {
+            try {
+                output.writeByte(19);
                 writeExpr(statement.getObjectRef());
             } catch (IOException e) {
                 throw new IOExceptionWrapper(e);
@@ -328,7 +336,7 @@ public class AstIO {
         @Override
         public void visit(MonitorExitStatement statement) {
             try {
-                output.writeByte(19);
+                output.writeByte(20);
                 writeExpr(statement.getObjectRef());
             } catch (IOException e) {
                 throw new IOExceptionWrapper(e);
diff --git a/teavm-core/src/main/java/org/teavm/cache/DiskRegularMethodNodeCache.java b/teavm-core/src/main/java/org/teavm/cache/DiskRegularMethodNodeCache.java
index bb6d058e0..a08e16bfd 100644
--- a/teavm-core/src/main/java/org/teavm/cache/DiskRegularMethodNodeCache.java
+++ b/teavm-core/src/main/java/org/teavm/cache/DiskRegularMethodNodeCache.java
@@ -262,6 +262,10 @@ public class DiskRegularMethodNodeCache implements RegularMethodNodeCache {
         public void visit(GotoPartStatement statement) {
         }
 
+        @Override
+        public void visit(SaveStatement statement) {
+        }
+
         @Override
         public void visit(MonitorEnterStatement statement) {
 
diff --git a/teavm-core/src/main/java/org/teavm/javascript/BreakToContinueReplacer.java b/teavm-core/src/main/java/org/teavm/javascript/BreakToContinueReplacer.java
index f80c3f981..6e17963fb 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/BreakToContinueReplacer.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/BreakToContinueReplacer.java
@@ -117,6 +117,10 @@ class BreakToContinueReplacer implements StatementVisitor {
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
     }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/CertainBlockCountVisitor.java b/teavm-core/src/main/java/org/teavm/javascript/CertainBlockCountVisitor.java
index 11702da38..7892d98b4 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/CertainBlockCountVisitor.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/CertainBlockCountVisitor.java
@@ -112,6 +112,10 @@ class CertainBlockCountVisitor implements StatementVisitor {
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
     }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java b/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java
index 88c3745fb..40ad05685 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/Decompiler.java
@@ -22,6 +22,7 @@ import org.teavm.javascript.spi.GeneratedBy;
 import org.teavm.javascript.spi.Generator;
 import org.teavm.javascript.spi.InjectedBy;
 import org.teavm.model.*;
+import org.teavm.model.instructions.InvokeInstruction;
 import org.teavm.model.util.AsyncProgramSplitter;
 import org.teavm.model.util.ProgramUtils;
 
@@ -294,7 +295,6 @@ public class Decompiler {
                 int tmp = indexer.nodeAt(next);
                 generator.nextBlock = tmp >= 0 && next < indexer.size() ? program.basicBlockAt(tmp) : null;
                 generator.statements.clear();
-                generator.asyncTarget = null;
                 InstructionLocation lastLocation = null;
                 NodeLocation nodeLocation = null;
                 List<Instruction> instructions = generator.currentBlock.getInstructions();
@@ -307,11 +307,17 @@ public class Decompiler {
                     if (insn.getLocation() != null) {
                         generator.setCurrentLocation(nodeLocation);
                     }
-                    if (targetBlocks[node] >= 0 && j == instructions.size() - 1) {
-                        generator.asyncTarget = targetBlocks[node];
-                    }
                     insn.acceptVisitor(generator);
+                    if (j == 0 && insn instanceof InvokeInstruction) {
+                        generator.statements.add(new SaveStatement());
+                    }
                 }
+                if (targetBlocks[node] >= 0) {
+                    GotoPartStatement stmt = new GotoPartStatement();
+                    stmt.setPart(targetBlocks[node]);
+                    generator.statements.add(stmt);
+                }
+
                 for (TryCatchBlock tryCatch : generator.currentBlock.getTryCatchBlocks()) {
                     TryCatchStatement tryCatchStmt = new TryCatchStatement();
                     tryCatchStmt.setExceptionType(tryCatch.getExceptionType());
diff --git a/teavm-core/src/main/java/org/teavm/javascript/NameFrequencyEstimator.java b/teavm-core/src/main/java/org/teavm/javascript/NameFrequencyEstimator.java
index fdfade618..20773208e 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/NameFrequencyEstimator.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/NameFrequencyEstimator.java
@@ -191,6 +191,10 @@ public class NameFrequencyEstimator implements StatementVisitor, ExprVisitor, Me
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
         if (async) {
diff --git a/teavm-core/src/main/java/org/teavm/javascript/OptimizingVisitor.java b/teavm-core/src/main/java/org/teavm/javascript/OptimizingVisitor.java
index f155919c4..eb9369618 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/OptimizingVisitor.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/OptimizingVisitor.java
@@ -619,6 +619,11 @@ class OptimizingVisitor implements StatementVisitor, ExprVisitor {
         resultStmt = statement;
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+        resultStmt = statement;
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
         statement.getObjectRef().acceptVisitor(this);
diff --git a/teavm-core/src/main/java/org/teavm/javascript/RedundantLabelEliminator.java b/teavm-core/src/main/java/org/teavm/javascript/RedundantLabelEliminator.java
index c0d240ebd..25c8bd389 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/RedundantLabelEliminator.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/RedundantLabelEliminator.java
@@ -122,6 +122,10 @@ class RedundantLabelEliminator implements StatementVisitor {
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
     }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ReferenceCountingVisitor.java b/teavm-core/src/main/java/org/teavm/javascript/ReferenceCountingVisitor.java
index 031ca7d2a..d9714e86b 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/ReferenceCountingVisitor.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/ReferenceCountingVisitor.java
@@ -116,6 +116,10 @@ class ReferenceCountingVisitor implements StatementVisitor {
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
     }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/Renderer.java b/teavm-core/src/main/java/org/teavm/javascript/Renderer.java
index 78abe9d5a..f5faaeeb3 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/Renderer.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/Renderer.java
@@ -716,6 +716,7 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
                 writer.softNewLine();
                 writer.outdent().append("}").softNewLine();
 
+                writer.append("while").ws().append("(true)").ws().append("{").indent().softNewLine();
                 writer.append("$main: switch").ws().append("($ptr)").ws().append('{').softNewLine();
                 for (int i = 0; i < methodNode.getBody().size(); ++i) {
                     writer.append("case ").append(i).append(":").indent().softNewLine();
@@ -724,6 +725,7 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
                     writer.outdent();
                 }
                 writer.append("}").softNewLine();
+                writer.outdent().append("}").softNewLine();
             } catch (IOException e) {
                 throw new RenderingException("IO error occured", e);
             }
@@ -1956,23 +1958,26 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
         }
     }
 
-
     @Override
     public void visit(GotoPartStatement statement) {
         try {
-            gotoPart(statement.getPart());
+            writer.append("$ptr").ws().append("=").ws().append(statement.getPart()).append(";")
+                    .softNewLine();
+            writer.append("break $main;").softNewLine();
         } catch (IOException ex){
             throw new RenderingException("IO error occured", ex);
         }
     }
 
-    private void gotoPart(int part) throws IOException {
-        writer.append("$ptr").ws().append("=").ws().append(part).append(";")
-                .softNewLine();
-        writer.append("if").ws().append("($rt_suspending())").ws().append("{").indent().softNewLine();
-        writer.append("return $save();").softNewLine();
-        writer.outdent().append("}").softNewLine();
-        writer.append("break $main;").softNewLine();
+    @Override
+    public void visit(SaveStatement statement) {
+        try {
+            writer.append("if").ws().append("($rt_suspending())").ws().append("{").indent().softNewLine();
+            writer.append("return $save();").softNewLine();
+            writer.outdent().append("}").softNewLine();
+        } catch (IOException ex){
+            throw new RenderingException("IO error occured", ex);
+        }
     }
 
     @Override
@@ -1984,9 +1989,9 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
                 writer.appendMethodBody(monitorEnterRef).append("(");
                 statement.getObjectRef().acceptVisitor(this);
                 writer.append(");").softNewLine();
-                if (statement.getAsyncTarget() != null) {
-                    gotoPart(statement.getAsyncTarget());
-                }
+                writer.append("if").ws().append("($rt_suspending())").ws().append("{").indent().softNewLine();
+                writer.append("return $save();").softNewLine();
+                writer.outdent().append("}").softNewLine();
             } else {
                 MethodReference monitorEnterRef = new MethodReference(
                         Object.class, "monitorEnterSync", Object.class, void.class);
diff --git a/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java b/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java
index 604bb2f3c..4b9665225 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/StatementGenerator.java
@@ -37,7 +37,6 @@ class StatementGenerator implements InstructionVisitor {
     Program program;
     ClassHolderSource classSource;
     private NodeLocation currentLocation;
-    Integer asyncTarget;
 
     public void setCurrentLocation(NodeLocation currentLocation) {
         this.currentLocation = currentLocation;
@@ -557,11 +556,6 @@ class StatementGenerator implements InstructionVisitor {
             stmt.setLocation(currentLocation);
             statements.add(stmt);
         }
-        if (asyncTarget != null) {
-            GotoPartStatement gotoStmt = new GotoPartStatement();
-            gotoStmt.setPart(asyncTarget);
-            statements.add(gotoStmt);
-        }
     }
 
     @Override
@@ -662,7 +656,6 @@ class StatementGenerator implements InstructionVisitor {
         MonitorEnterStatement stmt = new MonitorEnterStatement();
         stmt.setLocation(currentLocation);
         stmt.setObjectRef(Expr.var(insn.getObjectRef().getIndex()));
-        stmt.setAsyncTarget(asyncTarget);
         statements.add(stmt);
     }
 
diff --git a/teavm-core/src/main/java/org/teavm/javascript/TryCatchFinder.java b/teavm-core/src/main/java/org/teavm/javascript/TryCatchFinder.java
index 6bc07c4f0..3f65ad2b8 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/TryCatchFinder.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/TryCatchFinder.java
@@ -115,6 +115,10 @@ class TryCatchFinder implements StatementVisitor {
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
     }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/UnusedVariableEliminator.java b/teavm-core/src/main/java/org/teavm/javascript/UnusedVariableEliminator.java
index 82c00b82a..b828f31b5 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/UnusedVariableEliminator.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/UnusedVariableEliminator.java
@@ -229,6 +229,10 @@ class UnusedVariableEliminator implements ExprVisitor, StatementVisitor {
     public void visit(GotoPartStatement statement) {
     }
 
+    @Override
+    public void visit(SaveStatement statement) {
+    }
+
     @Override
     public void visit(MonitorEnterStatement statement) {
         statement.getObjectRef().acceptVisitor(this);
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ast/MonitorEnterStatement.java b/teavm-core/src/main/java/org/teavm/javascript/ast/MonitorEnterStatement.java
index 476d7820a..a7479337f 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/ast/MonitorEnterStatement.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/ast/MonitorEnterStatement.java
@@ -22,7 +22,6 @@ package org.teavm.javascript.ast;
 public class MonitorEnterStatement extends Statement {
     private NodeLocation location;
     private Expr objectRef;
-    private Integer asyncTarget;
 
     @Override
     public void acceptVisitor(StatementVisitor visitor) {
@@ -44,12 +43,4 @@ public class MonitorEnterStatement extends Statement {
     public void setObjectRef(Expr objectRef) {
         this.objectRef = objectRef;
     }
-
-    public Integer getAsyncTarget() {
-        return asyncTarget;
-    }
-
-    public void setAsyncTarget(Integer asyncTarget) {
-        this.asyncTarget = asyncTarget;
-    }
 }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ast/RenamingVisitor.java b/teavm-core/src/main/java/org/teavm/javascript/ast/RenamingVisitor.java
index 1bb1cfccd..db5e26719 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/ast/RenamingVisitor.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/ast/RenamingVisitor.java
@@ -197,12 +197,14 @@ public class RenamingVisitor implements StatementVisitor, ExprVisitor {
     }
 
     @Override
-    public void visit(MonitorEnterStatement statement) {
+    public void visit(SaveStatement statement) {
+    }
 
+    @Override
+    public void visit(MonitorEnterStatement statement) {
     }
 
     @Override
     public void visit(MonitorExitStatement statement) {
-
     }
 }
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ast/SaveStatement.java b/teavm-core/src/main/java/org/teavm/javascript/ast/SaveStatement.java
new file mode 100644
index 000000000..8e8c955b1
--- /dev/null
+++ b/teavm-core/src/main/java/org/teavm/javascript/ast/SaveStatement.java
@@ -0,0 +1,27 @@
+/*
+ *  Copyright 2015 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.javascript.ast;
+
+/**
+ *
+ * @author Alexey Andreev
+ */
+public class SaveStatement extends Statement {
+    @Override
+    public void acceptVisitor(StatementVisitor visitor) {
+        visitor.visit(this);
+    }
+}
diff --git a/teavm-core/src/main/java/org/teavm/javascript/ast/StatementVisitor.java b/teavm-core/src/main/java/org/teavm/javascript/ast/StatementVisitor.java
index 7194cdb4e..7c4f6cf9b 100644
--- a/teavm-core/src/main/java/org/teavm/javascript/ast/StatementVisitor.java
+++ b/teavm-core/src/main/java/org/teavm/javascript/ast/StatementVisitor.java
@@ -49,4 +49,6 @@ public interface StatementVisitor {
     void visit(MonitorEnterStatement statement);
 
     void visit(MonitorExitStatement statement);
+
+    void visit(SaveStatement statement);
 }
diff --git a/teavm-core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java b/teavm-core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java
index 81d174be4..e3b3ccde0 100644
--- a/teavm-core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java
+++ b/teavm-core/src/main/java/org/teavm/model/util/AsyncProgramSplitter.java
@@ -74,7 +74,7 @@ public class AsyncProgramSplitter {
                 // If we met asynchronous invocation...
                 // Copy portion of current block from last occurrence (or from start) to i'th instruction.
                 targetBlock.getInstructions().addAll(ProgramUtils.copyInstructions(sourceBlock,
-                        last, i + 1, targetBlock.getProgram()));
+                        last, i, targetBlock.getProgram()));
                 targetBlock.getTryCatchBlocks().addAll(ProgramUtils.copyTryCatches(sourceBlock,
                         targetBlock.getProgram()));
                 for (TryCatchBlock tryCatch : targetBlock.getTryCatchBlocks()) {
@@ -85,7 +85,7 @@ public class AsyncProgramSplitter {
                         queue.add(next);
                     }
                 }
-                last = i + 1;
+                last = i;
 
                 // If this instruction already separates program, end with current block and refer to the
                 // existing part
diff --git a/teavm-platform/src/main/java/org/teavm/platform/Platform.java b/teavm-platform/src/main/java/org/teavm/platform/Platform.java
index cbf6fe506..749b9d0b5 100644
--- a/teavm-platform/src/main/java/org/teavm/platform/Platform.java
+++ b/teavm-platform/src/main/java/org/teavm/platform/Platform.java
@@ -107,7 +107,7 @@ public final class Platform {
 
     @GeneratedBy(PlatformGenerator.class)
     @PluggableDependency(PlatformGenerator.class)
-    public static native void startThread(PlatformRunnable runnable);
+    public static native void startThread(PlatformRunnable runnable, boolean newNativeThread);
 
     private static void launchThread(PlatformRunnable runnable) {
         runnable.run();