INT 2F U - Novell DOS 7 - EMM386.EXE - MULTITASKING API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. - SUPERVISOR MODULE
	AX = 2780h
	CL = 01h (module: Supervisor)
	CH = subfunction
	    00h unused
		Return: CX = status (0002h) (see #02739)
	    01h unused
		Return: CX = status (0002h) (see #02739)
	    02h "Z_ModuleReg" register an OS module
		EBX = module number (0005h-000Fh)
		DS:EDX -> module descriptor (see #02741)
		Return: CX = status (0000h,0030h) (see #02739)
	    03h allocate SYSDAT memory
		DX = number of ??? to allocate
		Return: CX = status (0000h,0003h) (see #02739)
	    04h get selector to SYSDAT
		Return: CX = 0000h (successful)
			BX = selector for EMM386 data segment
			EBX high word cleared
	    05h "Z_MoveReal" relocate segment into extended memory
		DS:EDX -> descriptor parameter block
		Return: ECX = status (00h,03h,31h,32h) (see #02739)
			---if successful---
			parameter block filled
	    06h "Z_Reboot" return to real mode via triple fault
	    07h debugger break
		Note:	calls INT 03, then INT 21/AH=02h to output a question
			  mark
	    08h "X_ForeCheck" check if domain is in foreground
		Return: CX = 0000h (successful)
			EBX = ??? (0 or 2)
	    09h register VxDA virtual device driver for Windows 3.x or 95.	So called because nearly all of the Windows 3.0 drivers had names of the form "VdeviceD". See also device driver. with system
	    0Ah unload VxDA virtual device driver for Windows 3.x or 95.	So called because nearly all of the Windows 3.0 drivers had names of the form "VdeviceD". See also device driver. hook
	    0Bh indicate end of initialization phase
		Return: CX = status (0002h) (see #02739)
	    0Ch "F_AllocWindow" allocate 4K mapping window
	    0Dh "F_RegisterBoot" register reboot addresses
		EBX = ???
		EDX = ???
		Return: ???
	    0Eh "F_EnquireBoot" check if reboot active
		Return: CX = 0000h (successful)
			BL = ???     \ or BX = 0000h
			BH = ???     /
	    0Fh get debugging level
		Return: CX = 0000h (successful)
			EBX = new value for debugging level
	    10h set debugging level
		EDX = ???
		Return: CX = 0000h (successful)
			EBX = old value of debugging level
	    11h installation check (documented)
		Return: CX = status
			    0000h if multitasker is installed
				EBX = version (0100h for v1.00)
			    1101h if multitasker is not present
	    12h "F_V86BPInstall" install V86see Virtual-86 Mode breakpoint
		DX = ???
		Return: CX = 0000h (successful)
			AX = old value of ???
	    13h "F_V86BPRemove" remove V86see Virtual-86 Mode breakpoint
		Return: CX = status (0000h,003Fh) (see #02739)
			AX = ???
	    14h "F_V86BPOffer" indicate INT 03 to be used as V86see Virtual-86 Mode breakpoint
		EDX = linear address ??? of INT 03 instruction for breakpoint
		Return: CX = status (0000h,003Fh) (see #02739)
	    15h "F_LoaderCleanup" offer opportunity to clean up
		BX = segment of ???
		Return: CX = 0000h (successful)
			BX = segment of ???
	    16h "F_RegisterVxDWindow" register VxDA virtual device driver for Windows 3.x or 95.	So called because nearly all of the Windows 3.0 drivers had names of the form "VdeviceD". See also device driver. mapping window
	    17h "F_RegisterPNW" register Personal NetWare information
		EBX = subfunction (0-2)
		Return: CX = status (0002h if EBX>2) (see #02739)
			???
	    18h unused
		Return: CX = status (0002h) (see #02739)
Return: CX = status (most subfunctions)
	(E)AX and/or (E)BX contain return values, depending on function
Notes:	called by DPMSsee DOS Protected-Mode Services.EXE and EMM386.EXE
	this API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. is only available if AX=12FFh/BX=0EDCh returns successfully;
	  because the request is handled on the initial trap to the memory
	  manager caused by INT instructions, this API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. must be invoked with
	  an actual INT 2F instruction instead of some simulation such as a
	  far call to the address in the interrupt vector table
SeeAlso: AX=12FFh/BX=0EDCh,AX=2780h/CL=02h,AX=2780h/CL=03h,AX=2780h/CL=04h


(Table 02739)
Values for Novell DOS 7 EMM386 function status:
 0000h	successful
 0001h	not implemented
 0002h	invalid subfunction
 0003h	unable to find memory
 0004h	invalid flag (semaphore) number
 0005h	flag (semaphore) overrun
 0006h	flag (semaphore) underrun
 0007h	no queue handles available
 0009h	no queue buffers available
 000Ah	queue is in use
 000Bh	invalid process handle
 000Ch	no process handles available
 000Dh	queue access not permitted
 000Eh	queue is empty
 000Fh	queue is full
 0012h	no memory handles available
 0014h	can't find process in process list
 001Bh	invalid memory handle
 0023h	unable to terminate process
 002Ah	flag set ignored
 002Dh	no more system flags
 002Eh	flag (semaphore) not in idle state
 002Fh	flag (semaphore) wait timed out
 0030h	bad module number in CL
 0031h	bad descriptor
	invalid value for DESC_PB_SINFO in a descriptor parameter block
 0032h	no free descriptors
 0033h	error while locking/unlocking a page
 0034h	error getting or setting a page
 0035h	no pages available
 0036h	invalid domain
 0037h	process already frozen
 0038h	process not frozen
 0039h	fork failure (no registered swaplist)
 003Ah	page already free
 003Bh	page already allocated
 003Ch	unable to switch tasks
 003Dh	attempted to free critical section which is not active
 003Eh	too many active critical sections
 003Fh	???
 41FFh	current domain is invalid, or no domain in context
 42FFh	domain ID is not a valid descriptor
 43FFh	domain creation still in progress
 44FFh	domain currently being deleted
 45FFh	task manager is busy, cannot unload it
 46FFh	task manager already loaded
 47FFh	task manager not yet loaded
 48FFh	cannot save/restore because prior switch not complete
 49FFh	console already has owner
 4BFFh	unsupported opcode
 4CFFh	32-bit address prefix not supported
 4FFFh	timeout, but not on timer queue
 50FFh	unable to lock timer queue
 53FFh	unable to switch while in Global Message Mode
 54FFh	error while setting Global Message Mode
 55FFh	not in Global Message Mode
 56FFh	system already in Domain Message Mode
 57FFh	not in Domain Message Mode
 58FFh	unable to allocate timeout structure
 59FFh	unsupported video type
 5AFFh	function not handled by any VMsee Virtual Machine
 5BFFh	error in Serial..Set call
 5CFFh	error in Parallel..Set call
 5DFFh	domain list overflowed
 5FFFh	unable to free domain while in nobuffers mode


Format of Novell DOS/OpenDOS EMM386 descriptor parameter block:
Offset	Size	Description	(Table 02740)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	"DESC_PB_BASE"
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	"DESC_PB_LIMIT"
 08h	WORD	"DESC_PB_SEL"
 0Ah	BYTE	"DESC_PB_MINFO"
 0Bh	BYTE	"DESC_PB_SINFO"
SeeAlso: #02741


Format of Novell DOS/OpenDOS EMM386 module descriptor:
Offset	Size	Description	(Table 02741)
 00h 12 BYTEs	descriptor parameter block (see #02740)
 0Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	-> module entry point
Note:	for function "Z_ModuleReg", only DESC_PB_SEL and the module entry point
	  need to be initialized before calling EMM386
SeeAlso: #02740