--- old/src/cpu/x86/vm/x86_64.ad	Wed Feb 15 11:46:30 2012
+++ new/src/cpu/x86/vm/x86_64.ad	Wed Feb 15 11:46:30 2012
@@ -853,121 +853,53 @@
 
 //=============================================================================
 #ifndef PRODUCT
-void MachPrologNode::format(PhaseRegAlloc* ra_, outputStream* st) const
-{
+void MachPrologNode::format(PhaseRegAlloc* ra_, outputStream* st) const {
   Compile* C = ra_->C;
 
   int framesize = C->frame_slots() << LogBytesPerInt;
   assert((framesize & (StackAlignmentInBytes-1)) == 0, "frame size not aligned");
-  // Remove wordSize for return adr already pushed
-  // and another for the RBP we are going to save
-  framesize -= 2*wordSize;
-  bool need_nop = true;
+  // Remove wordSize for return addr which is already pushed.
+  framesize -= wordSize;
 
-  // Calls to C2R adapters often do not accept exceptional returns.
-  // We require that their callers must bang for them.  But be
-  // careful, because some VM calls (such as call site linkage) can
-  // use several kilobytes of stack.  But the stack safety zone should
-  // account for that.  See bugs 4446381, 4468289, 4497237.
   if (C->need_stack_bang(framesize)) {
-    st->print_cr("# stack bang"); st->print("\t");
-    need_nop = false;
+    framesize -= wordSize;
+    st->print("# stack bang");
+    st->print("\n\t");
+    st->print("pushq   rbp\t# Save rbp");
+    if (framesize) {
+      st->print("\n\t");
+      st->print("subq    rsp, #%d\t# Create frame",framesize);
+    }
+  } else {
+    st->print("subq    rsp, #%d\t# Create frame",framesize);
+    st->print("\n\t");
+    framesize -= wordSize;
+    st->print("movq    [rsp + #%d], rbp\t# Save rbp",framesize);
   }
-  st->print_cr("pushq   rbp"); st->print("\t");
 
   if (VerifyStackAtCalls) {
-    // Majik cookie to verify stack depth
-    st->print_cr("pushq   0xffffffffbadb100d"
-                  "\t# Majik cookie for stack depth check");
-    st->print("\t");
-    framesize -= wordSize; // Remove 2 for cookie
-    need_nop = false;
+    st->print("\n\t");
+    framesize -= wordSize;
+    st->print("movq    [rsp + #%d], 0xbadb100d\t# Majik cookie for stack depth check",framesize);
+#ifdef ASSERT
+    st->print("\n\t");
+    st->print("# stack alignment check");
+#endif
   }
-
-  if (framesize) {
-    st->print("subq    rsp, #%d\t# Create frame", framesize);
-    if (framesize < 0x80 && need_nop) {
-      st->print("\n\tnop\t# nop for patch_verified_entry");
-    }
-  }
+  st->cr();
 }
 #endif
 
-void MachPrologNode::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const
-{
+void MachPrologNode::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {
   Compile* C = ra_->C;
+  MacroAssembler _masm(&cbuf);
 
-  // WARNING: Initial instruction MUST be 5 bytes or longer so that
-  // NativeJump::patch_verified_entry will be able to patch out the entry
-  // code safely. The fldcw is ok at 6 bytes, the push to verify stack
-  // depth is ok at 5 bytes, the frame allocation can be either 3 or
-  // 6 bytes. So if we don't do the fldcw or the push then we must
-  // use the 6 byte frame allocation even if we have no frame. :-(
-  // If method sets FPU control word do it now
-
   int framesize = C->frame_slots() << LogBytesPerInt;
-  assert((framesize & (StackAlignmentInBytes-1)) == 0, "frame size not aligned");
-  // Remove wordSize for return adr already pushed
-  // and another for the RBP we are going to save
-  framesize -= 2*wordSize;
-  bool need_nop = true;
 
-  // Calls to C2R adapters often do not accept exceptional returns.
-  // We require that their callers must bang for them.  But be
-  // careful, because some VM calls (such as call site linkage) can
-  // use several kilobytes of stack.  But the stack safety zone should
-  // account for that.  See bugs 4446381, 4468289, 4497237.
-  if (C->need_stack_bang(framesize)) {
-    MacroAssembler masm(&cbuf);
-    masm.generate_stack_overflow_check(framesize);
-    need_nop = false;
-  }
+  __ verified_entry(framesize, C->need_stack_bang(framesize), false);
 
-  // We always push rbp so that on return to interpreter rbp will be
-  // restored correctly and we can correct the stack.
-  emit_opcode(cbuf, 0x50 | RBP_enc);
-
-  if (VerifyStackAtCalls) {
-    // Majik cookie to verify stack depth
-    emit_opcode(cbuf, 0x68); // pushq (sign-extended) 0xbadb100d
-    emit_d32(cbuf, 0xbadb100d);
-    framesize -= wordSize; // Remove 2 for cookie
-    need_nop = false;
-  }
-
-  if (framesize) {
-    emit_opcode(cbuf, Assembler::REX_W);
-    if (framesize < 0x80) {
-      emit_opcode(cbuf, 0x83);   // sub  SP,#framesize
-      emit_rm(cbuf, 0x3, 0x05, RSP_enc);
-      emit_d8(cbuf, framesize);
-      if (need_nop) {
-        emit_opcode(cbuf, 0x90); // nop
-      }
-    } else {
-      emit_opcode(cbuf, 0x81);   // sub  SP,#framesize
-      emit_rm(cbuf, 0x3, 0x05, RSP_enc);
-      emit_d32(cbuf, framesize);
-    }
-  }
-
   C->set_frame_complete(cbuf.insts_size());
 
-#ifdef ASSERT
-  if (VerifyStackAtCalls) {
-    Label L;
-    MacroAssembler masm(&cbuf);
-    masm.push(rax);
-    masm.mov(rax, rsp);
-    masm.andptr(rax, StackAlignmentInBytes-1);
-    masm.cmpptr(rax, StackAlignmentInBytes-wordSize);
-    masm.pop(rax);
-    masm.jcc(Assembler::equal, L);
-    masm.stop("Stack is not properly aligned!");
-    masm.bind(L);
-  }
-#endif
-
   if (C->has_mach_constant_base_node()) {
     // NOTE: We set the table base offset here because users might be
     // emitted before MachConstantBaseNode.