INT 17 - Enhanced Parallel Port (EPP) BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. - INSTALLATION CHECK
	AX = 0200h
	BX = 5050h ('PP')
	CH = 45h   ('E')
	DX = printer port number (00h-02h)
Return: AH = status
	    00h if installed and port is an enhanced parallel port
		CX:AL = installed BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. type
		    5050h:45h ('PPE') if EPP v3.0+ BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. installed
		    4550h:50h ('EPP') if EPP v1.0 BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. installed
		---EPP 1.0, 3.0---
		DX:BX -> far entry point to Advanced BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. (see #00632)
		---EPP Revision 7---
		DX = EPP I/O base address
		ES:BX -> far entry point to EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. (see #00632,#00633)
	    03h if installed but specified port not supported
		CF set
Program: The Enhanced Parallel Port BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. provides support for parallel
	  port peripherals using the enhanced modes of the IEEE 1284.
SeeAlso: AH=E0h,MEM 0040h:0008h,MEM 0040h:00DCh


(Table 00632)
Call EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. entry point with:
	DL = port number (v1.0,v3.0)
	DX = (Revision 7) EPP port I/O base address
	AH = function
	    00h Query Configuration
		Return: AH = 00h if successful
			    AL = IRQ(Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated. number used by port or FFh if no IRQ(Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated.
			    BH = EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. revision (major in high nybble,
				  minor in low nybble)
			    BL = I/O capabilities (see #00635)
			    ES:DI -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. driver information/version text
			    ---v1.0,v3.0---
			    CX = I/O port base address for parallel port
			    ---Revision 7---
			    CL = EPP chipset code (see #00636)
			    CH = hardware manufacturer's product code
	    01h Set Mode
		AL = mode bits (see #00637)
		Return: AX,BX destroyed
	    02h Get Mode
		Return: AL = mode bits (see also #00637)
				bit 7: EPP port interrupts enabled
			AH = 00h
			CF clear
			BX destroyed
	    03h Interrupt Control
		AL = subfunction
		    00h enable parallel port interrupts
		    01h disable parallel port interrupts
		Return: AH = status (00h,05h,06h) (see also #00634)
	    04h EPP Reset
		Return: AH = 00h if successful
			AL destroyed
	    05h perform Address-Write/Device-Select I/O cycle
		AL = device address
		Return: AH = status
			AL destroyed
	    06h perform Address-Read I/O cycle
		Return: AL = returned address/device data
			AH = status
	    07h write byte
		AL = data byte to write
		Return: AH = status
	    08h output block of data
		DS:SI -> block of data to be sent to parallel port
		CX = number of bytes to output
		Return: AH = status (see #00634)
			CX = number of unsent bytes
	    09h read byte of data
		Return: AH = status (see #00634)
			AL = byte read from parallel port
	    0Ah read block of data
		ES:DI -> buffer for received data
		CX = number of bytes to read from paralle port
		Return: AH = status (see #00634)
			ES:DI buffer filled if successful
			CX = number of bytes not transferred
	    0Bh Address/Byte-Read
		AL = device address
		Return: AH = status (see #00634)
			AL = byte read if successful
	    0Ch Address/Byte-Write
		AL = device address
		DH = data byte (v1.0,v3.0)
		CL = data byte (Revision 7)
		Return: AH = status (see #00634)
	    0Dh Address/Block-Read
		AL = device address
		ES:DI -> buffer for received data
		CX = number of bytes to read
		Return: AH = status (see #00634)
			CX = number of bytes NOT transferred
	    0Eh Address/Block-Write
		AL = device address
		ES:DI -> data to be sent (v1.0,v3.0)
		DS:SI -> data to be send (Revision 7)
		CX = number of bytes to write
		Return: AH = status (see #00634)
			CX = number of bytes NOT transferred
	    0Fh Lock Port
		AL = multiplexor port number
			bits 7-4: daisy chain port number (1-8)
			bits 3-0: mux device port number (1-8, 0 if no mux)
		Return: AH = status (00h,03h,05h) (see #00634)
	    10h Unlock Port
		AL = multiplexor port number
			bits 7-4: daisy chain port number (1-8)
			bits 3-0: mux device port number (1-8, 0 if no mux)
		Return: AH = status (00h,03h,05h) (see #00634)
	    11h Device Interrupt
		BL = multiplexor port number
			00h if no multiplexor, else mux device port (01h-08h)
		AL = subfunction
		    00h disable device interrupts
		    01h enable device interrupt
			ES:DI -> interrupt event handler
		Return: AH = status (00h,03h,05h,06h) (see #00634)
		Note:	AMIAmerican Megatrends, Inc.(American Megatrends, Inc.) A hardware, software and firmware company founded in 1985. BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. v1.00.12.AX1T ignores the multiplexor port
			  number; it also always sets INT 0F to the address
			  specified in ES:DI
	    12h Real-Time Mode
		AL = subfunction
		    00h check whether any real-time devices present
		    01h add (advertise) real-time device
		    02h remove real-time device
		Return: AH = status (00h,05h,06h,07h) (see #00634)
			AL = real-time devices present? (00h no, 01h yes)
		Note:	unlike all other functions, this one does not use DL/DX
Return: AH = status (see #00634)
	CF clear if successful
	CF set on error
	BX destroyed
SeeAlso: #00633


(Table 00633)
Call EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. (Revision 7) entry point multiplexor functions with:
	DX = EPP port base I/O address
	AH = function
	    40h Query Mux
		Return: AH = status (see #00634)
			AL = currently-selected port
			CH = status flags
				bit 0: channel locked
				bit 1: interrupt pending
			BH destroyed
		Note:	the PhoenixBIOS v4.0 documentation lists BL as the
			  currently-selected port and AL as the status flags
	    41h Query Device Port
		AL = EPP multiplex device port (1-8)
		Return: AH = status (see #00634)
			CH = status flags (see #00638)
			BX = EPP product/device ID (0000h if undefined)
		Note:	the PhoenixBIOS v4.0 documentation lists AL as the
			  status flags and CX as the device ID
	    42h Set Product ID
		AL = EPP multiplex device port (1-8)
		CX = EPP product ID
		Return: AH = status (see #00634)
			BX destroyed
	    50h Query Daisy Chain
		AL = EPP multiplexor device port (1-8)
		Return: AH = status (see #00634)
			CH = status flags
				bit 0: channel locked
				bit 1: interrupt pending
			BL = currently-selected device
			BH = EPP daisy chain revision (high nybble = major)
			CL = daisy-chain depth (00h if no daisy chain)
			ES:DI -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. driver vendor identification string
		Note:	the PhoenixBIOS v4.0 documentation lists AH=51h as
			  "Query Daisy Chain" and BL as the multiplexor port;
			  it also lists AL as status flags on return
	    51h Rescan Daisy Chain (dynamically reassign port numbers)
		AL = EPP multiplexor device port (1-8)
		Return: AH = status (see #00634)
			BX destroyed
		Note:	the PhoenixBIOS v4.0 documentation lists AH=50h as
			  "Rescan Daisy Chain" and BL as the multiplexor port
Notes:	these functions are only valid if a port multiplexor or daisy chain
	  is present
	PhoenixBIOS 4.0 documents function 50h as "Rescan" and 51h as
	  "Query Daisy Chain"
SeeAlso: #00632,INT 2D/AL=DCh


(Table 00634)
Values for EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. function status:
 00h	successful
 02h	unsupported command/feature
 03h	unsupported parallel port
 05h	unsupported in current mode
 06h	invalid subfunction
 07h	already ???
 20h	multiplexor not present (AMIAmerican Megatrends, Inc.(American Megatrends, Inc.) A hardware, software and firmware company founded in 1985.)
 40h	multiplexor not present
 41h	multiplexor currently locked
 80h	I/O timeout
 FFh	invalid/unsupported function
SeeAlso: #00632,#00633


Bitfields for EPP (v3.0, Revision 7) I/O capabilities:
Bit(s)	Description	(Table 00635)
 0	multiplexor present
 1	PS/2IBM PS/2, any model bi-directional capable
 2	daisy chain present
 3	ECP capable
 4	EPP software emulation supported
 5	EPP capable
 6	fast Centronics supported
 7	standard EPP I/O map
SeeAlso: #00632


(Table 00636)
Values for EPP (Revision 7) chipset code:
 00h	Intel SL
 01h	FarPoint Communications
 02h	SMC
 03h	Chips&Technologies
 04h	Western Digital
 05h	National Semiconductor
SeeAlso: #00632


Bitfields for EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. mode bits:
Bit(s)	Description	(Table 00637)
 0	set compatibility mode
 1	set bi-directional mode
 2	set EPP mode
---Revision 7,v3.0---
 3	set ECP mode
 4	set EPP software emulation
 5	set fast Centronics mode
 6-7 reserved (0)
SeeAlso: #00632,#M0053


Bitfields for EPP BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. multiplex status flags:
Bit(s)	Description	(Table 00638)
 0	port is selected
 1	port is locked
 2	interrupts are enabled
 3	interrupt pending
SeeAlso: #00633