VM.assert(isPageAligned(address) && isPageMultiple(size));
VM._assert(isPageAligned(address) && isPageMultiple(size));
  public static VM_Address mmapFile(VM_Address address, int size, int fd, int prot) {    if (VM.VerifyAssertions)      VM.assert(isPageAligned(address) && isPageMultiple(size));    VM_BootRecord bootRecord = VM_BootRecord.the_boot_record;    return VM_Address.fromInt(VM.sysCall4(bootRecord.sysMMapGeneralFileIP, address.toInt(), size, fd, prot));  }