INT 15 - Advanced Power Management Specification - GET POWER MANAGEMENT EVENT
        AX = 530Bh
Return: CF clear if successful
            BX = event code
                0001h system stand-by request
                0002h system suspend request
                0003h normal resume system notification
                0004h critical resume system notification
                0005h battery low notification
        CF set on error
            AH = error code (03h,80h) (see AX=5300h)
Notes:  although power management events are often asynchronous, notification
          will not be made until polled via this call to permit software to
          only receive event notification when it is prepared to process
          power management events; since these events are not very time-
          critical, it should be sufficient to poll once or twice per second
        the critical resume notification is made after the system resumes
          from an emergency suspension; normally, the system BIOS only notifies
          its partner that it wishes to suspend and relies on the partner to
          actually request the suspension, but no notification is made on an
          emergency suspension
        should not be called from within a hardware interrupt handler to avoid
          reentrance problems
SeeAlso: AX=5307h/BX=0001h/CX=0001h,AX=5307h/BX=0001h/CX=0002h