VM.assert(isPageAligned(address) && isPageMultiple(size));
VM._assert(isPageAligned(address) && isPageMultiple(size));
  public static int munmap(VM_Address address, int size) {    if (VM.VerifyAssertions)      VM.assert(isPageAligned(address) && isPageMultiple(size));    VM_BootRecord bootRecord = VM_BootRecord.the_boot_record;    return VM.sysCall2(bootRecord.sysMUnmapIP, address.toInt(), size);  }