INT 31 P - DPMIsee DOS Protected-Mode Interface 1.0+ - SERIALIZE SHARED MEMORY
	AX = 0D02h
	SI:DI = shared memory block handle
	DX = flags
	    bit 0: return immediately rather than suspending if serialization
		  unavailable
	    bit 1: shared rather than exclusive serialization
	    bits 2-15 reserved (0)
Return: CF clear if successful
	CF set on error
	    AX = error code (8004h,8005h,8017h-8019h,8023h) (see #03143)
Notes:	an exclusive serialization blocks any other serialization attempts for
	  the same block by another virtual machine; a shared serialization
	  blocks attempts at exclusive serialization by another virtual machine
	hosts are not required to detect deadlock
	a client's interrupt handler can cancel a serialization call which
	  caused it to block by calling AX=0D03h
SeeAlso: AX=0D00h,AX=0D03h