Index for interrupt INT 4B

Table of Contents by Order
4B - INT 4B - Z100 - Slave 8259 - S100 vectored line 3
4B - INT 4B - Common Access Method SCSI interface (draft revision 1.9)
4B - INT 4B - Tandy 2000 - EQUIPMENT DETERMINATION
4B - INT 4B - Acorn BBC Master 512 - "OSBYTE" - MISC FUNCTIONS USING REGISTER PARAMS
4B00 - INT 4B - TI Professional PC - PARALLEL PORT - OUTPUT CHARACTER
4B01 - INT 4B - TI Professional PC - PARALLEL PORT - INITIALIZE PRINTER
4B02 - INT 4B - TI Professional PC - PARALLEL PORT - GET PRINTER STATUS
4B80 - INT 4B - IBM SCSI interface
4B8102DX0000 - INT 4B - Virtual DMA Specification (VDS) - GET VERSION
4B8103 - INT 4B - Virtual DMA Specification - LOCK DMA REGION
4B8104 - INT 4B - Virtual DMA Specification - UNLOCK DMA REGION
4B8105 - INT 4B - Virtual DMA Specification - SCATTER/GATHER LOCK REGION
4B8106 - INT 4B - Virtual DMA Specification - SCATTER/GATHER UNLOCK REGION
4B8107 - INT 4B - Virtual DMA Specification - REQUEST DMA BUFFER
4B8108 - INT 4B - Virtual DMA Specification - RELEASE DMA BUFFFER
4B8109DX0000 - INT 4B - Virtual DMA Specification - COPY INTO DMA BUFFER
4B810ADX0000 - INT 4B - Virtual DMA Specification - COPY OUT OF DMA BUFFER
4B810B - INT 4B - Virtual DMA Specification - DISABLE DMA TRANSLATION
4B810C - INT 4B - Virtual DMA Specification - ENABLE DMA TRANSLATION
4B810D - INT 4B - QEMM-386 - BUG

INT 4B - Z100 - Slave 8259 - S100 vectored line 3
SeeAlso: INT 4A"Z100",INT 4C"Z100"

INT 4B - Common Access Method SCSI interface (draft revision 1.9)
	ES:DI -> CAM Control Block (see #03229 at INT 4F/AX=8100h)
InstallCheck:	test for the string "SCSI_CAM" eight bytes past the INT 4Bh
	  handler
Notes:	the CAM committee moved the interface to INT 4F after revision 1.9
	  to avoid conflicting with the IBM SCSI interface and the Virtual
	  DMA specification
	the only driver to date reported to use the CAM interface on INT 4B
	  instead of INT 4F is from Future Domain (which has drivers for CAM
	  on either interrupt)
SeeAlso: INT 4F/AX=8100h
Index:	installation check;Common Access Method SCSI interface

INT 4B - Tandy 2000 - EQUIPMENT DETERMINATION
Return: AX = BIOS equipment list word (see #03215)
Note:	this interrupt is identical to INT 11 on the Tandy 2000
SeeAlso: INT 11"EQUIPMENT",INT 4A"Tandy 2000",INT 4C"Tandy 2000"

Bitfields for Tandy 2000 BIOS equipment list:
Bit(s)	Description	(Table 03215)
 0	reserved
 1	monochrome graphics installed
 2	graphics with color option installed
 3	floppy disk drive 1 installed
 4	floppy disk drive 2 installed
 5	hard disk drive 1 installed
 6	hard disk drive 2 installed
 7	unused
 8	black and white monitor
 9	color monitor
 12-10	reserved
 13	printer installed
 14	reserved
 15	unused
SeeAlso: #00226 at INT 11

INT 4B - Acorn BBC Master 512 - "OSBYTE" - MISC FUNCTIONS USING REGISTER PARAMS
	AL = function code
	BL = first parameter
	BH = second parameter (if needed)
Return: BL = first return parameter
	BH = second return parameter
	CF depends on function
SeeAlso: INT 40"Acorn",INT 4A"Acorn",INT 4C"Acorn"

INT 4B - TI Professional PC - PARALLEL PORT - OUTPUT CHARACTER
	AH = 00h
	DL = printer number (00h)
	AL = character to print
Return: AH = printer status (see #03216)
Note:	on the TI Pro, the BIOS only supports DL=00h; MS-DOS versions for the
	  TI hook INT 4B and handle requests for DL<>00h
SeeAlso: AH=01h,AH=02h,INT 17/AH=00h
SeeAlso: INT 40"TI Professional",INT 48/AH=00h"TI Professional"
SeeAlso: INT 49/AH=01h"TI",INT 4C"TI Professional",INT 4D/AH=00h

Bitfields for TI Professional PC printer status:
Bit(s)	Description	(Table 03216)
 0	timeout (function 00h only)
 3-1	unused
 4	busy
 5	paper out
 6	on-line (selected)
 7	fault

INT 4B - TI Professional PC - PARALLEL PORT - INITIALIZE PRINTER
	AH = 01h
	DL = printer number (00h)
Return: AH = printer status (see #03216)
Note:	on the TI Pro, the BIOS only supports DL=00h; MS-DOS versions for the
	  TI hook INT 4B and handle requests for DL<>00h
SeeAlso: AH=00h,AH=02h,INT 17/AH=01h

INT 4B - TI Professional PC - PARALLEL PORT - GET PRINTER STATUS
	AH = 02h
	DL = printer number (00h)
Return: AH = printer status (see #03216)
Note:	on the TI Pro, the BIOS only supports DL=00h; MS-DOS versions for the
	  TI hook INT 4B and handle requests for DL<>00h
SeeAlso: AH=00h,AH=01h,INT 17/AH=02h

INT 4B - IBM SCSI interface
	AH = 80h
	AL = 00h-10h (Corel PowerSCSI INT4BCAM.SYS)
	further details not yet available

INT 4B - Virtual DMA Specification (VDS) - GET VERSION
	AX = 8102h
	DX = 0000h
Return: CF clear if successful
	    AH = major version number
	    AL = minor version number
	    BX = product number (see #03217)
	    CX = product revision number
		always 0000h for QMAPS and HPMM.SYS
		always 0001h for Microsoft's EMM386.EXE v4.20-4.41
	    DX = flags (see #03219)
	    SI:DI = maximum DMA buffer size
	CF set on error
	    AL = error code (see #03218)
Note:	bit 5 of 0040h:007Bh is supposed to be set if VDS is supported; this is
	  apparently not always the case
SeeAlso: INT 2C/AX=002Bh,INT 31/AX=0400h,MEM 0040h:007Bh"4Bh"
Index:	installation check;Virtual DMA Specification

(Table 03217)
Values for VDS product number:
 0000h	for Quadtel's QMAPS and Hewlett-Packard's HPMM.SYS
 0001h	for Microsoft's EMM386.EXE
 0003h	for Windows 3.x WIN386.EXE
 0300h	OS/2 (all versions to date)
 0EDCh	for DR DOS 6.0 EMM386.SYS
 4560h	("E`") for Qualitas' 386MAX
 4D43h	("MC") for V Communications' Memory Commander
 5145h	("QE") for Quarterdeck's QEMM-386
 524Dh	("RM") for Helix's Netroom RM386

(Table 03218)
Values for VDS error code:
 01h	region not in contiguous memory
 02h	region crossed a physical alignment boundary
 03h	unable to lock pages
 04h	no buffer available
 05h	region too large for buffer
 06h	buffer currently in use
 07h	invalid memory region
 08h	region was not locked
 09h	number of physical pages greater than table length
 0Ah	invalid buffer ID
 0Bh	copy out of buffer range
 0Ch	invalid DMA channel number
 0Dh	disable count overflow
 0Eh	disable count underflow
 0Fh	function not supported
 10h	reserved flag bits set in DX

Bitfields for VDS flags:
Bit(s)	Description	(Table 03219)
 0	PC/XT bus (DMA in first megabyte only)
 1	physical buffer/remap region in first megabyte
 2	automatic remap enabled
 3	all memory is physically contiguous
 4-15	reserved (zero)

INT 4B - Virtual DMA Specification - LOCK DMA REGION
	AX = 8103h
	DX = flags (see #03220)
	ES:DI -> DMA descriptor structure (see #03221,#03222,#03223)
Return: CF clear if successful
	    DDS physical address field filled in
	    DDS buffer ID field filled (0000h if no buffer allocated)
	CF set on error
	    AL = error code (see #03218)
	    DDS region size field filled wth maximum contiguous length in bytes
BUGS:	Windows 3.0 does not correctly support automatic remapping or copying
	  in enhanced mode
	Windows 3.0 in enhanced mode does not return a correct code on error
SeeAlso: AX=8104h,AX=8105h

Bitfields for VDS flags:
Bit(s)	Description	(Table 03220)
 0	reserved (zero)
 1	data should be copied into buffer (ignored if 2 set)
 2	buffer should not be allocated if region noncontiguous or crosses
	  physical alignment boundary specified by 4-5
 3	don't attempt automatic remap
 4	region must not cross 64K physical alignment boundary
 5	region must not cross 128K physical alignment boundary
 6-15	reserved (zero)

Format of DMA descriptor structure (DDS):
Offset	Size	Description	(Table 03221)
 00h	DWORD	region size
 04h	DWORD	offset
 08h	WORD	segment/selector
 0Ah	WORD	buffer ID
 0Ch	DWORD	physical address

Format of Extended DMA descriptor structure (EDDS):
Offset	Size	Description	(Table 03222)
 00h	DWORD	region size
 04h	DWORD	offset
 08h	WORD	segment/selector
 0Ah	WORD	reserved
 0Ch	WORD	number available
 0Eh	WORD	number used
 10h	DWORD	region 0 physical address
 14h	DWORD	region 0 size in bytes
 18h	DWORD	region 1 physical address
 1Ch	DWORD	region 1 size in bytes
	...

Format of Extended DMA descriptor structure (EDDS) with page table entries:
Offset	Size	Description	(Table 03223)
 00h	DWORD	region size
 04h	DWORD	offset
 08h	WORD	segment/selector
 0Ah	WORD	reserved
 0Ch	WORD	number available
 0Eh	WORD	number used
 10h	DWORD	page table entry 0 (same as 80386 page table entry)
 14h	DWORD	page table entry 1
	...
Note:	bits 1-11 of the page table entries should be zero; bit 0 set if page
	  is present and locked

INT 4B - Virtual DMA Specification - UNLOCK DMA REGION
	AX = 8104h
	DX = flags
	    bit 0: reserved (zero)
	    bit 1: data should be copied out of buffer
	    bits 2-15 reserved (zero)
	ES:DI -> DMA descriptor structure (see #03221,#03222) with region size,
		  physical address, and buffer ID fields set
Return: CF clear if successful
	    DDS physical address field set
	    DDS buffer ID field set (0000h if no buffer allocated)
	CF set on error
	    AL = error code (see #03218)
	    DDS region size field filled wth maximum contiguous length in bytes
Note:	Windows 3.0 does not check whether the region extends beyond the end of
	  a segment
BUG:	Windows 3.0 in enhanced mode does not return a correct code on error
SeeAlso: AX=8103h,AX=8106h

INT 4B - Virtual DMA Specification - SCATTER/GATHER LOCK REGION
	AX = 8105h
	DX = flags (see #03224)
	ES:DI -> Extended DMA descriptor structure (see #03222,#03223)
		  region size, linear segment, linear offset, and number avail
		  fields set
Return: CF clear if successful
	    EDDS number used field set
	    if DX bit 6 set, lower 12 bits of BX = offset in first page
	CF set on error
	    AL = error code (see #03218)
	    EDDS region size field filled with max length in bytes that can be
		  locked and described in the EDDS table
BUG:	Windows 3.0 in enhanced mode may return zero instead of the physical
	  page address for pages which were originally not present
SeeAlso: AX=8103h,AX=8106h

Bitfields for VDS flags:
Bit(s)	Description	(Table 03224)
 0-5	reserved (zero)
 6	EDDS should be returned with page table entries
 7	only present pages should be locked (not-present pages receive entry
	  of 0000h)
 8-15	reserved (zero)

INT 4B - Virtual DMA Specification - SCATTER/GATHER UNLOCK REGION
	AX = 8106h
	DX = flags (see #03225)
	ES:DI -> Extended DMA descriptor structure (see #03222,#03223) returned
		  by AX=8105h
Return: CF clear if successful
	CF set on error
	    AL = error code (see #03218)
Note:	according to the Microsoft version of the VDS specification, the
	  actual scatter/gather list is ignored, while according to the IBM
	  version of the specification, "the result of a LOCK operation"
	  must be provided to this function
SeeAlso: AX=8104h,AX=8105h

Bitfields for VDS flags:
Bit(s)	Description	(Table 03225)
 0-5	reserved (zero)
 6	EDDS contains page table entries
 7	EDDS may contain not-present pages (entry = 0000h)
 8-15	reserved (zero)

INT 4B - Virtual DMA Specification - REQUEST DMA BUFFER
	AX = 8107h
	DX = flags
	    bit 0: reserved (zero)
	    bit 1: data should be copied into buffer
	    bits  2-15 reserved (zero)
	ES:DI -> DMA descriptor structure (see #03221) with region size set
		  (also region offset and region segment if DX bit 1 set)
Return: CF clear if successful
	    DDS physical address and buffer ID set
	    DDS region size filled with length of buffer
	CF set on error
	    AL = error code (see #03218)
SeeAlso: AX=8108h

INT 4B - Virtual DMA Specification - RELEASE DMA BUFFFER
	AX = 8108h
	DX = flags
	    bit 0: reserved (zero)
	    bit 1: data should be copied out of buffer
	    bits 2-15 reserved (zero)
	ES:DI -> DMA descriptor structure (see #03221,#03222) with buffer ID set
		  (also region size/region offset/segment if DX bit 1 set)
Return: CF clear if successful
	CF set on error
	    AL = error code (see #03218)
BUG:	under Windows 3.0 Enhanced mode, you must specify that data be copied
	  for this function to work correctly
SeeAlso: AX=8107h

INT 4B - Virtual DMA Specification - COPY INTO DMA BUFFER
	AX = 8109h
	DX = 0000h
	ES:DI -> DMA descriptor structure (see #03221,#03222) with buffer ID,
		  region segment/offset, and region size fields set
	BX:CX = starting offset into DMA buffer
Return: CF clear if successful
	CF set on error
	    AL = error code (see #03218)
BUG:	Windows 3.0 Enhanced mode does not correctly interpret the copy count
SeeAlso: AX=810Ah

INT 4B - Virtual DMA Specification - COPY OUT OF DMA BUFFER
	AX = 810Ah
	DX = 0000h
	ES:DI -> DMA descriptor structure (see #03221,#03223) with buffer ID,
		  region segment/offset, and region size fields set
	BX:CX = starting offset into DMA buffer
Return: CF clear if successful
	CF set on error
	    AL = error code (see #03218)
BUG:	Windows 3.0 Enhanced mode does not correctly interpret the copy count
SeeAlso: AX=8109h

INT 4B - Virtual DMA Specification - DISABLE DMA TRANSLATION
	AX = 810Bh
	BX = DMA channel number
	DX = 0000h
Return: CF clear if successful
	CF set on error
	    AL = error code (see #03218)
SeeAlso: AX=810Ch

INT 4B - Virtual DMA Specification - ENABLE DMA TRANSLATION
	AX = 810Ch
	BX = DMA channel number
	DX = 0000h
Return: CF clear if successful
	    ZF set if disable count decremented to zero
	CF set on error
	    AL = error code (see #03218)
SeeAlso: AX=810Bh

INT 4B - QEMM-386 - BUG
	AX = 810Dh
Note:	the code in QEMM v5.11 and 6.00 jumps to an invalid location on this
	  call