INT 7F - Alloy NTNX, MW386 - SEMAPHORE LOCK AND WAIT
        AH = 00h
        DS:DX -> ASCIZ semaphore name (max 64 bytes)
Return: AL = status (see below)
        AH = semaphore owner if status=02h
SeeAlso: AH=01h,AH=02h,AH=41h,INT 67/AH=00h

Values for status:
 00h    successful
 01h    invalid function
 02h    semaphore already locked
 03h    unable to lock/unlock semaphore
 04h    semaphore space exhausted
 05h    host/target PC did not respond (NTNX)

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