public VM_Address sub (int v) throws VM_PragmaLogicallyUninterruptible {
public VM_Address sub (VM_Extent extent) throws VM_PragmaLogicallyUninterruptible {
  public VM_Address sub (int v) throws VM_PragmaLogicallyUninterruptible {    if (VM.VerifyAssertions && VM.runningVM) VM._assert(VM.NOT_REACHED);  // call site should have been hijacked by magic in compiler    return new VM_Address(value - v);  }