if (VM.VerifyAssertions) VM.assert(isPageAligned(start) && isPageMultiple(len));
if (VM.VerifyAssertions) VM._assert(isPageAligned(start) && isPageMultiple(len));
  public static void zeroPages(VM_Address start, int len) {    if (VM.VerifyAssertions) VM.assert(isPageAligned(start) && isPageMultiple(len));    VM_BootRecord bootRecord = VM_BootRecord.the_boot_record;    VM.sysCall2(bootRecord.sysZeroPagesIP, start.toInt(), len);  }