Vbe20

VESA®
Video Electronics Standards Association
2150NorthFirst Street, Suite 440 Phone: (408) 435-0333
San Jose, CA 95131-2029 FAX: (408) 435-8225
VESA BIOS EXTENSION (VBE)
Core Functions
Standard
Version: 2.0
Document Revision: 1.1
Ratification Date: November 18, 1994
Purpose
Tostandardizeamodular,softwareinterfacetodisplayandaudiodevices. TheVBEinterfaceis
intendedtosimplifyandencouragethedevelopmentofapplicationsthatwishtousegraphics, video, and
audiodeviceswithoutspecificknowledgeoftheinternaloperationoftheevolvingtargethardware.
Summary
TheVBEstandarddefines aset ofextensions totheVGAROMBIOSservices. These functions can
beaccessedunderDOSthroughinterrupt 10h, orbecalleddirectlybyhighperformance32-bit
applicationsandoperatingsystems otherthanDOS.
Theseextensionsalsoprovideahardware-independentmechanismtoobtainvendorinformation, and
serveasanextensiblefoundationforOEMsandVESAtofacilitaterapidsoftwaresupport ofemerging
hardwaretechnologywithoutsacrificingbackwardscompatibility.
VBE Core Standard

Page ii VBECOREFUNCTIONSVERSION2.0
DOCUMENTREVISION1.1

VBECOREFUNCTIONSVERSION2.0 Pageiii
DOCUMENTREVISION1.1
Intellectual Property
Copyright©1993,1995-VideoElectronics Standards Association. Duplicationofthis document
withinVESAmembercompaniesforreviewpurposes is permitted. Thisdocumentmaybe posted
onlineinitsunmodified,read-onlyformatonly.Nocharges,otherthanstandardconnect ordownload
charges,maybeassessedforthis document. Allotherrightsreserved.
Whileeveryprecautionhasbeentakeninthepreparationofthis standard, theVideoElectronics
StandardsAssociationanditscontributorsassumenoresponsibilityforerrors oromissions, andmake
nowarranties,expressedorimplied,offunctionalityorsuitabilityforanypurpose.
Thesamplecodecontainedwithin thisstandardmaybeusedwithout restriction.
Trademarks
Alltrademarksusedinthisdocument arepropertyoftheirrespectiveowners.
• VESA, VBE, VESADDC, VBE/AI, VBE/PM, and VBE/DDCare trademarks ofVideo
ElectronicsStandardsAssociation.
• MS-DOSand Windows are trademarks ofMicrosoft , Inc.
• IBM, VGA, EGA, CGA, andMDAaretrademarks ofInternational Business Machines
• RAMDACis a trademark ofBrooktree Corp.
• HerculesisatrademarkofHercules ComputerTechnology, Inc.
Patents
VESAproposal andstandards documents areadoptedbytheVideoElectronics Standards Association
withoutregardtowhethertheiradoptionmayinvolvepatents onarticles, materials, orprocesses. Such
adoptiondoesnotassumeanyliabilitytoanypatentowner, nordoes it assumeanyobligationwhatever
toparties adoptingtheproposal orstandards document.
Support for this Specification
Clarificationsandapplicationnotestosupportthisstandardwill bepublishedas theneedarises. To
obtainthelateststandardandsupport documentation, contact VESA.
Ifyouhaveaproductwhichincorporates VBE, youshouldaskthecompanythat manufacturedyour
productforassistance. Ifyouareadisplayorcontrollermanufacturer, VESAcanassist youwithany
clarificationyoumayrequire. AllcommentsorreportederrorsshouldbesubmittedinwritingtoVESA
usingoneofthefollowingmechanisms:
World Wide Web: www.vesa.org Mail to:
E-mail: techsupport@vesa.org VideoElectronicsStandardsAssociation
Fax: 408-435-8225 2150NorthFirst Street, Suite 440
Voice: 408-435-0333 SanJose, California95131-2029

Page iv VBECOREFUNCTIONSVERSION2.0
DOCUMENTREVISION1.1
SSC/VBE Workgroup Members
Anyindustrystandardrequiresinput frommanysources. Thepeoplelistedbelowweremembers ofthe
VBEWorkgroupoftheSoftwareStandards Committee(SSC)whichwas responsibleforcombiningall
oftheindustryinputintothisproposal:
CHAIRMAN
Kevin Gillett, S-MOS Systems, Inc.,
past chairman, Rod Dewell , Excalibur Solutions
MEMBERS
David Penley, AT&T Global Information Solutions
Rebecca Nolan, Chips and Technologies, Inc.
Brad Haakenson, Cirrus Logic, Inc.
Joe Rickson, Logitech, Inc.
Aaron Leatherman, LSI Logic Corporation
Jake Richter, Panacea Inc.
Raluca Iovan, Phoenix Technologies Ltd.
Kendall Bennett, SciTech Software
Tom Ryan, SciTech Software
George Bystricky, S-MOS Systems, Inc.
Jason Li, Trident Microsystems, Inc.
Chris Tsang, ULSISystems
GregMoore, VideoElectronics Standards Association
Andy Lambrecht, VLSI Technology, Inc.
Rex Wolfe, Western Digital Imaging

VBECOREFUNCTIONSVERSION2.0 Page v
DOCUMENTREVISION1.1
Table of Contents
INTELLECTUAL PROPERTY .....................................................................................................................................................iii
TRADEMARKS ...................................................................................................................................................................................iii
PATENTS............................................................................................................................................................................................iii
SUPPORT FORTHISSPECIFICATION...................................................................................................................................iii
SSC/VBE WORKGROUPMEMBERS........................................................................................................................................iv
TABLE OFCONTENTS..................................................................................................................................................................v
1.0INTRODUCTION...................................................................................................................................................................... 1
1.1SCOPE OF THE VBESTANDARD...............................................................................................................................................1
1.2 BACKGROUNDER ........................................................................................................................................................................2
2.0 VBE OVERVIEW......................................................................................................................................................................5
2.1 VBE FEATURES...........................................................................................................................................................................5
2.2 VBE AFFECTEDDEVICES..........................................................................................................................................................5
2.3 PROVIDINGVENDORINFORMATION.......................................................................................................................................5
3.0 VBE MODE NUMBERS...........................................................................................................................................................6
4.0 VBE FUNCTIONS...................................................................................................................................................................10
4.1 VBE RETURN STATUS .............................................................................................................................................................10
4.2 PROTECTED MODE CONSIDERATIONS................................................................................................................................11
4.3 FUNCTION 00H - RETURN VBECONTROLLERINFORMATION.........................................................................................12
4.4 FUNCTION 01H - RETURN VBE MODE INFORMATION ......................................................................................................16
4.5 FUNCTION 02H - SET VBE MODE.........................................................................................................................................25
4.6 FUNCTION 03H - RETURN CURRENT VBE MODE...............................................................................................................26
4.7 FUNCTION 04H - SAVE/RESTORESTATE ............................................................................................................................27
4.8 FUNCTION 05H - DISPLAYWINDOW CONTROL.................................................................................................................27
4.9 FUNCTION 06H - SET/GET LOGICALSCANLINE LENGTH ................................................................................................28
4.10 FUNCTION 07H - SET/GET DISPLAYSTART ......................................................................................................................29
4.11 FUNCTION 08H - SET/GET DAC PALETTE FORMAT........................................................................................................30
4.12 FUNCTION 09H - SET/GET PALETTE DATA.......................................................................................................................30
4.13 FUNCTION 0AH - RETURN VBEPROTECTED MODE INTERFACE ..................................................................................31
5.0VBESUPPLEMENTAL SPECIFICATIONS......................................................................................................................34
5.1 PURPOSEOFSUPPLEMENTAL SPECIFICATIONS ................................................................................................................34
5.2 OBTAININGSUPPLEMENTAL VBEFUNCTIONNUMBERS.................................................................................................34
5.3 REQUIREDVBESUPPLEMENTAL SPECIFICATION COMPONENTS..................................................................................35
5.3.1 VBE Supplemental Specification Functions..............................................................................................................35
5.3.2 Return Status....................................................................................................................................................................35
5.3.3 Subfunction 00h - Return VBE Supplemental Specification Information ............................................................35
5.4 SUPPLEMENTAL SPECIFICATION PROTECTED MODE GUIDELINES..............................................................................38
5.5 LOADINGSUPPLEMENTAL DRIVERS ....................................................................................................................................39
5.6 IMPLEMENTATION QUESTIONS ............................................................................................................................................39

Page vi VBECOREFUNCTIONSVERSION2.0
DOCUMENTREVISION1.1
5.7 KNOWN SUPPLEMENTAL SPECIFICATIONS........................................................................................................................40
5.7.1 Function 10h - Power Management Extensions (PM).............................................................................................40
5.7.2 Function 11h - Flat Panel Interface Extensions (FP)..............................................................................................40
5.7.3 Function 12h - Cursor Interface Extensions (CI).....................................................................................................40
5.7.4 Function 13h - Audio Interface Extensions (AI) .......................................................................................................40
5.7.5 Function 14h - OEM Extensions ..................................................................................................................................40
5.7.6 Function 15h - Display Data Channel (DDC) ..........................................................................................................40
5.7.7 Function 16h - Graphics System Configuration (GC).............................................................................................40
APPENDIX1-VBEQUICKREFERENCE................................................................................................................................41
APPENDIX 2 - VBE DATA STRUCTURES..............................................................................................................................47
APPENDIX 3 - VBE SUPPLEMENTAL SPECS. .....................................................................................................................61
APPENDIX4-VBEIMPLEMENTATIONCONSIDERATIONS .........................................................................................63
A4.1 MINIMUM FUNCTIONALITY REQUIREMENTS..................................................................................................................63
A4.1.1 Required VBE Services...............................................................................................................................................63
A4.1.2 Minimum ROM Implementation................................................................................................................................63
A4.1.3 TSR Implementations ..................................................................................................................................................63
A4.2 VGA BIOS IMPLICATIONS....................................................................................................................................................64
A4.3 ROM SPACE LIMITATIONS..................................................................................................................................................65
A4.3.1 Data Storage ................................................................................................................................................................65
A4.3.2 Removal of Unused VGA Fonts .................................................................................................................................65
A4.3.3 Deleting VGA Parameter Tables...............................................................................................................................66
A4.3.4 Increasing ROM Space...............................................................................................................................................66
4.3.5 Support of VGA TTY Functions....................................................................................................................................66
A4.4 IMPLEMENTATION NOTESBY FUNCTION........................................................................................................................67
A4.4.1 General Notes...............................................................................................................................................................67
A4.4.2 Function 00h - Return VBE Controller Information.............................................................................................67
A4.4.3 Function 01h - Return VBE Mode Information......................................................................................................68
A4.4.4 Function 02h - Set VBE Mode...................................................................................................................................68
A4.4.5 Function 03h - Return Current VBE Mode.............................................................................................................69
A4.4.6 Function 05h - Display Window Control................................................................................................................69
A4.4.7 Function 06h - Get/Set Logical Scan Line Length................................................................................................70
A4.4.8 Function 07h - Get/Set Display Start ......................................................................................................................70
A4.4.9 Function 08h - Set/Get DAC Palette Format.........................................................................................................70
A4.4.10 Function 09h - Set/Get Palette Data......................................................................................................................70
A4.4.11 Function 0Ah - Return VBE Function Information..............................................................................................71
A4.5 PLUGANDPLAY ISSUES ........................................................................................................................................................71
A4.6 SUPPORTING MULTIPLE CONTROLLERS..........................................................................................................................71
A4.6.1 Dual-Controller Designs............................................................................................................................................71
A4.6.2 Provision for Multiple Independent Controllers...................................................................................................71
A4.7 DISPLAYREFRESHRATES ANDINTERLACING .................................................................................................................72
A4.8 OEM EXTENSIONSTOVBE ..................................................................................................................................................72
A4.9 CERTIFICATION REQUIREMENTS .......................................................................................................................................73
A4.9.1 VBETest Utility.............................................................................................................................................................73
A4.9.2 Communication with VESA Office............................................................................................................................73

VBECOREFUNCTIONSVERSION2.0 Pagevii
DOCUMENTREVISION1.1
APPENDIX5 - APPLICATIONPROGRAMMING CONSIDERATIONS..........................................................................74
A5.1 APPLICATION DEVELOPER'SSAMPLE SOURCE...............................................................................................................74
C Language Module.................................................................................................................................................................74
Assembly Language Module ...................................................................................................................................................84
A5.2 IMPLEMENTATION NOTESBY FUNCTION........................................................................................................................84
A5.2.1 General Notes...............................................................................................................................................................84
A5.2.2 Function 00h - Return VBE Controller Information.............................................................................................84
A5.2.3 Function 01h - Return VBE Mode Information......................................................................................................85
A5.2.4 Function 02h - Set VBE Mode...................................................................................................................................85
A5.2.5 Function 03h - Return Current VBE Mode.............................................................................................................86
A5.2.6 Function 05h - Display Window Control................................................................................................................86
A5.2.7 Function 06h - Get/Set Logical Scan Line Length................................................................................................86
A5.2.8 Function 07h - Get/Set Display Start ......................................................................................................................87
A5.2.9 Function 08h - Set/Get DAC Palette Format.........................................................................................................87
A5.2.10 Function 09h - Set/Get Palette Data......................................................................................................................87
A5.2.11 Function 0Ah - Return VBE Function Information..............................................................................................88
APPENDIX6-DIFFERENCESBETWEENVBE REVISIONS .............................................................................................89
6.1 VBE 1.0................................................................................................................................................................................89
6.2 VBE 1.1................................................................................................................................................................................89
6.3 VBE 1.2................................................................................................................................................................................89
6.4 VBE 2.0................................................................................................................................................................................89
6.5 VBE 2.0, Rev. 1.1................................................................................................................................................................90
APPENDIX7-RELATEDDOCUMENTS.................................................................................................................................93

Introduction
VBECOREFUNCTIONSVERSION2.0 Page1
DOCUMENTREVISION1.1
1.0 Introduction
This document contains the VESA BIOS Extension (VBE) specification for standard software access to
graphics displaycontrollers which support resolutions, color depths, and frame buffer organizations
beyond the VGA hardware standard. It is intended for use by both applications programmers and
system software developers.
System software developers may use this document to supplement the System and INT 10h ROM
BIOS functions to provide the VBE services. Application developers can use this document as a guide
to programming all VBE compatible devices.
To understand the VBE specification, some knowledge of 80x86 assembly language and the VGA
hardware registers may be required. However, the services described in this specification may be
called fromanyhigh-level programming language that provides a mechanism for generating software
interrupts with the 80x86 registers set to user-specified values.
In this specification, 'VBE' and 'VBE 2.0' are synonymous with 'VBE Core Functions version 2.0'.
1.1 Scope of the VBE Standard
TheprimarypurposeoftheVESAVBE is toprovidestandardsoftwaresupport forthemanyunique
implementationsofSuperVGA(SVGA)graphicscontrollersonthePCplatformthat providefeatures
beyondtheoriginalVGAhardwarestandard. Thisis toprovideafeasiblemechanismbywhich
applicationdeveloperscantakeadvantageofthisnonstandardhardwareingraphics applications.
TheVBEspecificationoffersanextensiblesoftwarefoundationwhichallowsittoevolveasdisplayand
audiodevicesevolveovertime,withoutsacrificingbackwardsoftwarecompatibilitywitholder
implementations. Newapplicationsoftwareshouldbeabletoworkwitholderhardware, and
applicationsoftwarethathasalreadyshippedshouldworkcorrectlyonnewhardwaredevices.
VBEservicesprovidestandardaccess toall resolutions andcolordepths providedonthedisplay
controller,andreporttheavailabilityanddetailsofallsupportedconfigurationstotheapplicationas
necessary.
VBEimplementationsfacilitatethefieldsupportofaudioanddisplayhardwarebyprovidingthe
applicationsoftwarewiththemanufacturer'snameandtheproductidentificationofthedisplay
hardware.
SincegraphicscontrollerservicesonthePCaretypicallyimplementedinROM, theVBEservices are
definedsothattheyshouldbeimplementedwithinthestandardVGAROM. WhenROM
implementations ofVBEarenot possible, orwhenfieldsoftwareupgrades totheonboardROMare
necessary, theVBEimplementationmaybealsoofferedas adevicedriverorDOSTerminateandStay
Resident(TSR)program.

Introduction
Page2 VBECOREFUNCTIONSVERSION2.0
DOCUMENTREVISION1.1
ThestandardVBEfunctions maybesupplementedbyOEM's as necessarytosupport customor
proprietaryfunctionsuniquetothemanufacturer. ThismechanismenablestheOEMtoestablish
functions that maybestandardtotheproduct line, orprovideaccess tospecial hardware
enhancements.
AlthoughpreviousVBEstandardsassumedthattheunderlyinggraphicsarchitecturewas aVGA
device,thedisplayservicesdescribedbyVBE2.0canbeimplementedonanyframebufferoriented
graphicsdevice.
ThemajorityofVBEservicesfacilitatethesetupandconfigurationofthehardware,allowing
applicationshighperformance,directaccesstotheconfigureddeviceatruntime. Tofurtherimprovethe
performanceofflatframebufferdisplaydevicesinextendedresolutions, VBE2.0provides new
memorymodelsthatdonotrequirethetraditionalframebuffer"banking"mechanisms.
VBEis expectedtoworkonall 80x86platforms, inreal and protected modes.
Sincesomemoderndisplaydevicesaredesignedwithout anyVGAsupport, twodisplaycontrollers
maybepresentinthesystem. OnedisplaycontrollerwouldbeusedforVGAcompatibility, andthe
otherusedforgraphicextensionstothebasicVGAmodes, resolutions, andframebuffermodels.
Therefore, VBEmust beableoffertheapplicationautomaticaccess totheappropriatedevicebasedon
themodeorresolutionthat is requestedbytheapplication.
CurrentlybeyondthescopeoftheVBEspecificationisthehandlingofhardwareconfigurationand
installationissues. It was originallyconsideredtobecomepart ofVBE2.0, howeverwehavedeferred
theissuestotheGraphicsConfigurationSupplementalSpecification. Inaddition,itisalsopossiblefor
anOEMtodefinetheirownextensionsusingtheOEMSupplementalSpecificationifrequired.
1.2 Backgrounder
TheIBMVGA1
has becomeadefactostandardinthePCgraphics world. Amultitudeofdifferent
VGAofferingsexistinthemarketplace,eachoneprovidingBIOSorregistercompatibilitywiththeIBM
VGA.MoreandmoreoftheseVGAcompatibleproducts implement various supersets oftheVGA
standard.Theseextensionsrangefromhigherresolutionsandmorecolors toimprovedperformanceand
evensomegraphicsprocessingcapabilities.Intensecompetitionhasdramaticallyimprovedthe
price/performanceratio, tothebenefit oftheenduser.
1
IBM and VGA are trademarks of International Business Machines Corporation.

Introduction
DOCUMENTREVISION1.1
However, several serious problems faceasoftwaredeveloperwhointends totakeadvantageofthese
"SuperVGA"2
environments.Becausethereisnostandardhardwareimplementation, thedeveloperis
facedwithwidelydifferentSuperVGAhardwarearchitecture.Lackingacommonsoftwareinterface,
designingapplicationsfortheseenvironmentsiscostlyandtechnicallydifficult.Exceptforapplications
supportedbyOEM-specificdisplaydrivers, veryfewsoftwarepackages cantakeadvantageofthe
powerandcapabilities ofSuperVGAproducts.
TheVBEstandardwasoriginallyconceivedtoenablethedevelopmentofapplications that wishedto
takeadvantageofdisplayresolutions andcolordepths beyondtheVGAdefinition. Theneedforan
applicationorsoftwarestandardwas recognizedbythedevelopers ofgraphichardwaretoencourage
theuseandacceptanceoftheirrapidlyadvancingproduct families. It becameobvious that themajority
ofsoftwareapplicationdevelopers didnot havetheresources todevelopandsupport customdevice
levelsoftwareforthehundreds ofdisplayboards onthemarket. Thereforetherichnewfeatures of
thesedisplaydeviceswerenotbeingusedoutsideoftherelativelysmall CADmarket, andonlythen
afterconsiderableeffort.
Indeed, theneedforastandardforSVGAdisplayadapters became so important that the VESA
organizationwasformedtoseekout asolution. Theoriginal VBEstandardwas devisedandagreed
uponbyeachoftheactivedisplaycontrollermanufacturers, andhas sincebeenadoptedbyDOS
applicationdeveloperstoenableuseofnon-VGAextendeddisplaymodes.
As timewent alongVBE1.1was createdtoaddmorevideomodes andincreasedlogical line
length/doublebufferingsupport. VBE1.2was createdtoaddmodes andalsoaddedhigh color
RAMDACsupport.
Inthethreeyears sinceVBE1.2was approved we have seen the standard become widelyaccepted
andmanysuccessful programs haveembracedVBE. However, it has becomeobvious that theneed
foramorerobustandextensiblestandardexists. Earlyextensions totheVGAstandardcontinuedusing
alloftheoriginalVGAI/Oportsandframebufferaddresstocommunicatewiththecontroller
hardware. Aswe'veseen,thesupportedresolutions andcolordepths havegrown, intelligent controllers
withBITBLTandLineDrawFunctionshavebecomecommon,andnewflat framebuffermemory
models haveappearedalongwithdisplaycontrollers that arenot basedonVGAinanyway. VBE2.0
andfutureextensionswillsupportnon-VGAbasedcontrollerswithnewfunctionsforreadingand
writingthepaletteandforaccess totheflat framebuffermodels.
2
The term "Super VGA" is used in this document for a graphics display controller implementing any superset of the
standard IBM VGA display adapter.

Introduction
DOCUMENTREVISION1.1
VBE2.0,asdesigned,offerstheextensibilityandtherobustness that was lackingintheprevious
specifications,whileatthesametimeofferingbackwardscompatibility.
Inthefuture,weseetheneedforaddingsupplementalspecificationsforissueslikeMultimedia;
AdvancedGraphicsFunctions;and"PlugandPlay"features.

VBE Overview
DOCUMENTREVISION1.1
2.0 VBE Overview
ThischapteroutlinesthevariousfeaturesandlimitationsoftheVBEstandard.
2.1 VBE Features
• StandardapplicationinterfacetoGraphicsControllers (SVGADevices).
• Standardmethodofidentifyingproductsandmanufacturers.
• ProvisionforOEMextensionsthroughSub-function14h.
• Simpleprotectedmodeinterface.
• Extensibleinterfacethroughsupplementalspecifications.
2.2 VBE Affected Devices
Allframebuffer-baseddevicesinthePCplatform(withtheexceptionofHercules, Monochrome
(MDA), CGAandEGAdevices)aresuitableforusewithintheVBEstandardtoenable access to the
devicebyVBE-compliantapplications.
2.3 Providing Vendor Information
TheVGAspecificationdoesnotprovideastandardmechanismtodeterminewhat graphicdeviceit is
runningon.OnlybyknowingOEM-specificfeaturescananapplicationdeterminethepresenceofa
particulargraphicscontrollerordisplayboard.Thisofteninvolvesreadingandtestingregisterslocated
atI/OaddressesuniquetoeachOEM. Bynot knowingwhat hardwareanapplicationis runningon,
few, ifany, oftheextendedfeatures ofthis hardwarecan be used.
TheVESABIOSExtensionprovidesseveralfunctionstoreturninformationaboutthegraphics
environment.Thesefunctionsreturnsystemlevelinformationaswellasgraphicsmodespecificdetails.
Function00hreturnsgeneralsystemlevelinformation,includinganOEMidentificationstring.The
functionalsoreturns apointertothesupportedVBEandOEMmodes. Function01h maybe used by
anapplicationtoobtainadditionalinformationabouteachsupportedmode.Function03hreturns the
currentVBEmode.

VBEModeNumbers
DOCUMENTREVISION1.1
3.0 VBE Mode Numbers
StandardVGAmodenumbers are7bits wideandpresentlyrange from00h to 13h. OEMs have
definedextendeddisplaymodes intherange14hto7Fh. Values from80htoFFhcannot beused, since
VGABIOSFunction00h(Set videomode)interprets bit 7as a flagto clear or preserve display
memory.
Duetothelimitationsof7-bit modenumbers, theoptional VBEmodenumbers are14bits wide. To
initializeaVBEmode,themodenumberis passedintheBXregistertoVBEFunction02h(Set VBE
mode).
TheformatofVBEmodenumbersisas follows:
D0-D8 = Modenumber
IfD8==0, this is not a VESAdefined mode
IfD8== 1, this is a VESAdefined mode
D9-D13 = ReservedbyVESAforfutureexpansion(=0)
D14 = Linear/FlatFrameBufferSelect
IfD14 == 0, Use VGA Frame Buffer
IfD14==1, UseLinear/Flat Frame Buffer
D15 = PreserveDisplayMemorySelect
IfD15==0, Clear displaymemory
IfD14==1, Preserve displaymemory
Thus,VBEmodenumbersbeginat100h.Thismodenumberingschemeimplements standard7-bit
modenumbersforOEM-definedmodes. StandardVGAmodes maybeinitializedthrough VBE
Function02h(SetVBEmode)simplybyplacingthemodenumberinBLandclearingtheupperbyte
(BH).7-bitOEM-defineddisplaymodes maybeinitializedinthesameway. Notethat modes mayonly
beset ifthemodeexists in the VideoModeList pointedtobytheVideoModePTRreturnedinFunction
00h. Theexceptiontothis requirement is themodenumber81FFh.
Todate, VESAhas definedonespecial 7-bit mode number, 6Ah, for the 800x600, 16-color, 4-plane
graphics mode. Thecorresponding15-bit modenumberforthis modeis 102h. ThefollowingVBE
modenumbershavebeendefined:
GRAPHICS TEXT
15-bit 7-bit Resolution Colors 15-bit 7-bit Columns Rows
mode mode mode mode
number number number number
100h - 640x400 256 108h - 80 60
101h - 640x480 256 109h - 132 25
102h 6Ah 800x600 16 10Ah - 132 43
103h - 800x600 256 10Bh - 132 50
104h - 1024x768 16 10Ch - 132 60
105h - 1024x768 256
106h - 1280x1024 16

VBEModeNumbers
DOCUMENTREVISION1.1
107h - 1280x1024 256

VBEModeNumbers
DOCUMENTREVISION1.1
GRAPHICS
15-bit 7-bit Resolution Colors
mode mode
number number
10Dh - 320x200 32K(1:5:5:5:)
10Eh - 320x200 64K(5:6:5)
10Fh - 320x200 16.8M(8:8:8)
110h - 640x480 32K(1:5:5:5:)
111h - 640x480 64K(5:6:5)
112h - 640x480 16.8M(8:8:8)
113h - 800x600 32K(1:5:5:5:)
114h - 800x600 64K(5:6:5)
115h - 800x600 16.8M(8:8:8)
116h - 1024x768 32K(1:5:5:5:)
117h - 1024x768 64K(5:6:5)
118h - 1024x768 16.8M(8:8:8)
119h - 1280x1024 32K(1:5:5:5:)
11Ah - 1280x1024 64K(5:6:5)
11Bh - 1280x1024 16.8M(8:8:8)
81FFh Special Mode(seebelowfordetails)
Note: StartingwithVBEversion2.0,VESAwillnolongerdefinenewVESAmodenumbers andit will
notlongerbemandatorytosupport theseoldmodenumbers. However, it is highlyrecommendedthat
BIOSimplementationscontinuetosupportthesemodenumbersforcompatibilitywitholdersoftware.
VBE2.0-awareapplicationsshouldfollowtheguidelinesinAppendix5-ApplicationProgramming
Considerations -forsettingadesiredmode.
Note: Mode81FFhis aspecial modedesignedtopreservethecurrent memorycontents and give
accesstotheentirevideomemory. Thismodeisespeciallyusefulforsavingtheentirevideomemory
contents beforegoingintoastatethat couldlosethecontents (e.g., set this modetogainaccess toall
videomemorytosaveit beforegoingintoavolatilepowerdownstate). This modeis requiredbecause
theentirevideomemorycontents arenot always accessibleineverymode. It isrecommendedthat this
modebepackedpixel informat, andaModeInfoBlockmust bedefinedforit. However, it shouldnot
appearintheVideoModeList.LookintheModeInfoBlocktodetermineifpagingis requiredandhow
pagingissupportedifitis. Alsonotethattherearenoimpliedresolutionsortimingsassociatedwiththis
mode.
Note: FuturedisplayresolutionswillbedefinedbyVESAdisplayvendors. Thecolordepths will not
bespecifiedandnewmodenumbers will notbeassignedfortheseresolutions. Forexample, ifthe
VESAdisplayvendorsdefine1600x1200asaVESAresolution, applicationdevelopers shouldtarget
theirdisplayresolutionfor1600x1200ratherthanchoosinganarbitraryresolutionlike1550x1190.
TheVBEimplementationshouldbequeriedtogettheavailableresolutions andcolordepths andthe

VBEModeNumbers
DOCUMENTREVISION1.1
applicationshouldbeflexibleenoughtoworkwiththislist. Appendix5givesadetailedsummaryofthe
wayanapplicationshouldgoaboutselectingandsettingmodes.

VBEFunctions
DOCUMENTREVISION1.1
4.0 VBE Functions
Thischapterdescribesindetaileachofthefunctions definedbytheVBEstandard. VBEfunctions are
calledusingtheINT10hinterrupt vector, passingarguments inthe80X86registers. TheINT10h
interrupthandlerfirstdeterminesifaVBEfunctionhas beenrequested, andifso, processes that
request. Otherwisecontrol is passedtothestandardVGABIOSfor completion.
AllVBEfunctionsarecalledwiththeAHregistersetto4FhtodistinguishthemfromthestandardVGA
BIOSfunctions. TheALregisteris usedtoindicatewhichVBEfunctionis tobeperformed. For
supplementalorextendedfunctionalitytheBLregisterisusedwhenappropriatetoindicateaspecific
sub-function.
Functions00h-0FhhavebeenreservedforStandardVBEfunctionnumbers; Functions 10h-FFh are
reservedforVBESupplementalSpecifications.
InadditiontotheINT10hinterface, aProtectedModeInterfaceis availableand is described below.
4.1 VBE Return Status
TheAXregisterisusedtoindicatethecompletionstatus uponreturnfromVBEfunctions. IfVBE
supportforthespecifiedfunctionisavailable,the4FhvaluepassedintheAHregisteronentryis
returnedintheALregister. IftheVBEfunctioncompletedsuccessfully, 00his returnedintheAH
register. OtherwisetheAHregisteris set toindicatethenatureofthefailure.
VBERETURNSTATUS
AL == 4Fh: Functionissupported
AL != 4Fh: Functionisnotsupported
AH == 00h: Functioncallsuccessful
AH == 01h: Functioncallfailed
AH == 02h: Functionisnotsupportedinthecurrenthardwareconfiguration
AH == 03h: Functioncallinvalidincurrentvideomode
Note: Applicationsshouldtreatanynon-zerovalueintheAHregisterasageneral failureconditionas
laterversionsoftheVBEmaydefineadditional errorcodes.

VBEFunctions
00hReturnVBEControllerInformation
DOCUMENTREVISION1.1
4.2 Protected Mode Considerations
VBEservices maybecalleddirectlyfrom32-bit protectedmodeonly.
For32-bit protectedmode, 2selector/segment descriptors for 32-bit code and the data segment are
needed.Thesewillbeallocatedandinitializedbythecaller.Thesegmentlimitfieldswillbeset to64k.
TheseselectorsmayeitherbeintheGDTorLDT, but must bevalidwhenevertheVBEis calledin
protectedmode. Thecallermust supplyastacklargeenoughforusebyVBEandbypotential interrupt
handlers.Thecaller'sstackwillbeactiveiforwheninterrupts areenabledintheVBEroutine, sincethe
VBEwillnotswitchstackswheninterruptsareenabled,includingNMIinterrupts. The32-bit VBE
interfacerequires a32-bit stack.
Ifthememorylocationis zero, thenonlyI/Omappedports will beusedsotheapplicationdoes not
needtodoanythingspecial. This shouldbethedefault caseforALLcards that have I/Omapped
registersbecauseit provides thebest performance.
Ifthememorylocationis nonzero(therecanbeonlyone), theapplicationwill needtocreateanew32-
bitselectorwiththebaseaddressthatpointstothe“physical”locationspecifiedwiththespecifiedlimit.
Whentheapplicationneeds tocall the32-bitbankswitchfunction,itmustthenloadtheES selector
withthevalueofthenewselectorthat has beencreated. Thebankswitchingcodecanthen directly
accessitsmemorymappedregisters as absoluteoffsets intotheESselector
(i.e., mov[es:10],eaxtoput avalueintotheregisterat base+10).
It is uptotheapplicationcodetosaveandrestoretheprevious stateofthe ESselector ifthis is
necessary(forexampleinflat model code).
WhentheVBEservices arecalled, thecurrent I/Opermissionbit mapmust allowaccess tothe I/O
ports that theVBEmayneedtoaccess. This can be found in the Sub-Table (Ports and Memory)
returnedbyVBEFunction0Ah.
Tosummarize,itistheresponsibilityofthecallingtoensuretothat it has theappropriateI/Oand
memoryprivileges, andalargeenoughstackandappropriateselectors allocated. It is alsothe
responsibilityofthecallingapplicationtopreserveregistersifnecessary.
Applicationsmustusethesameregisters fortheFunction05handFunction09hprotectedmode
interfacethattheywoulduseinarealmodecall. This includes theAXregister.
Function07hprotectedmodecalls haveadifferent format.
AX = 4F07h
BL = 00h Set DisplayCRTCStart
= 80h SetDisplayCRTCStart duringVertical Retrace
CX = Bits 0-15ofdisplaystart address
DX = Bits 16-31ofdisplaystart address

VBEFunctions
DOCUMENTREVISION1.1
Theprotectedmodeapplicationmust keeptrackofthecolordepthandscanlinelengthtocalculatethe
newstartaddress. Ifavaluethat is out ofrangeis programmed, unpredictableresults will occur.
4.3 Function 00h - Return VBE Controller Information
Thisrequiredfunctionreturnsthecapabilitiesofthedisplaycontroller,therevisionleveloftheVBE
implementation,andvendorspecificinformationtoassistinsupportingalldisplaycontrollersinthefield.
Thepurposeofthisfunctionistoprovideinformationtothecallingprogramaboutthegeneral
capabilitiesoftheinstalledVBEsoftwareandhardware.Thisfunctionfillsaninformationblockstructure
attheaddressspecifiedbythecaller. TheVbeInfoBlockinformationblocksizeis 256bytes forVBE
1.x, and 512 bytes for VBE2.0.
Input: AX = 4F00h ReturnVBEControllerInformation
ES:DI = Pointertobufferinwhichtoplace
VbeInfoBlockstructure
(VbeSignatureshouldbeset to'VBE2'when
functioniscalledtoindicateVBE2.0information
isdesiredandtheinformationblockis 512bytes in
size.)
Output: AX = VBEReturnStatus
Note: Allotherregisters arepreserved.
Theinformationblockhasthefollowingstructure:
VbeInfoBlockstruc
VbeSignature db 'VESA' ;VBESignature
VbeVersion dw 0200h ;VBEVersion
OemStringPtr dd ? ;PointertoOEMString
Capabilities db 4 dup (?) ;Capabilitiesofgraphicscontroller
VideoModePtr dd ? ;PointertoVideoModeList
TotalMemory dw ? ; Numberof64kbmemoryblocks
; Added for VBE 2.0
OemSoftwareRev dw ? ;VBEimplementationSoftwarerevision
OemVendorNamePtr dd ? ;PointertoVendorNameString
OemProductNamePtr dd ? ; PointertoProduct NameString
OemProductRevPtr dd ? ;PointertoProductRevisionString
Reserved db 222 dup (?) ;ReservedforVBEimplementationscratch
; area
OemData db 256 dup (?) ; DataAreaforOEMStrings
VbeInfoBlockends

VBEFunctions
DOCUMENTREVISION1.1
Note: AlldatainthisstructureissubjecttochangebytheVBEimplementationwhenVBEFunction
00his called. Therefore, it shouldnot beusedbytheapplicationtostoredataofanykind.
DescriptionoftheVbeInfoBlockstructurefields:
The VbeSignaturefieldisfilledwiththeASCIIcharacters'VESA'bytheVBEimplementation.VBE
2.0applicationsshouldpreset this fieldwiththeASCIIcharacters 'VBE2'toindicatetotheVBE
implementationthattheVBE2.0extendedinformationisdesired,andtheVbeInfoBlockis 512bytes in
size. UponreturnfromVBEFunction00h, this fieldshouldalways beset to'VESA'bytheVBE
implementation.
The VbeVersionisaBCDvaluewhichspecifieswhatleveloftheVBEstandardis implementedinthe
software.Thehigherbytespecifiesthemajorversionnumber.Thelowerbytespecifies theminor
versionnumber.
Note: The BCDvalue for VBE2.0 is 0200h and the BCDvalue for VBE1.2 is 0102h. In the past we
havehadsomeapplicationsmisinterpretingtheseBCDvalues. Forexample, BCD0102hwas
interpretedas 1.02, whichis incorrect.
The OemStringPtrisaRealModefarpointertoanullterminatedOEM-definedstring. This stringmay
beusedtoidentifythegraphicscontrollerchiporOEMproduct familyforhardwarespecificdisplay
drivers.Therearenorestrictionsontheformat ofthestring. This pointermaypoint intoeitherROMor
RAM,dependingonthespecificimplementation. VBE2.0BIOSimplementationsmustplacethisstring
intheOemDataareawithintheVbeInfoBlockif'VBE2'is preset intheVbeSignaturefieldonentryto
Function00h. Thismakes it possibletoconvert theRealModeaddress toanoffset withinthe
VbeInfoBlockforProtectedmodeapplications.
Note: ThelengthoftheOEMStringis not defined, but forspaceconsiderations, werecommenda
stringlengthoflessthan256bytes.
The Capabilities fieldindicatesthesupportofspecificfeaturesinthegraphicsenvironment.Thebits
aredefinedasfollows:
D0 = 0 DACisfixedwidth, with6bits perprimarycolor
= 1 DACwidthis switchableto8bits perprimarycolor
D1 = 0 ControllerisVGAcompatible
= 1 ControllerisnotVGAcompatible
D2 = 0 NormalRAMDACoperation
= 1 WhenprogramminglargeblocksofinformationtotheRAMDAC,
usetheblankbitinFunction09h.
D3-31 =Reserved

VBEFunctions
DOCUMENTREVISION1.1
BIOSImplementationNote: TheDACmust always berestoredto 6 bits per primaryas default upon
amodeset. Ifthe DAChas been switched to 8 bits per primary, the mode set must restore the DAC
to6bits perprimarytoensuretheapplicationdeveloperthat he does not have to reset it.
Application Developer's Note: IfaDACis switchable, youcanassume that the DACwill be
restoredto6bits perprimaryupona mode set. For an application to use a DAC, the application
programisresponsibleforsettingtheDACto8bits perprimarymodeusingFunction08h.
VGAcompatibilityisdefinedas supportingall standardIBMVGAmodes, fonts andI/Oports;
however,VGAcompatibilitydoesn't guaranteethat all modes whichcanbeset areVGAcompatible, or
thatthe8x14fontisavailable.
TheneedforD2=1"programtheRAMDACusingtheblankbit inFunction09h"is forolderstyle
RAMDACs,whereprogrammingtheRAMvaluesduringdisplaytimecausesa"snow-like"effect on
thescreen. NewerstyleRAMDACs don't havethis limitationandcaneasilybeprogrammedat any
time,but olderRAMDACs requirethat theybeblankedsoas not todisplaythesnowwhilevalues
changeduringdisplaytime. Thisbitinformsthesoftwarethatitshouldmakethefunctioncallwith
BL=80hratherthanBL=00htoensuretheminimizationofthe"snow-like"effect.
The VideoModePtr points toalist of modenumbers forall displaymodes supported bythe VBE
implementation. Eachmodenumberoccupies oneword(16bits). Thelist ofmodenumbers is
terminatedbya-1(0FFFFh). Themodenumbers inthis list represent all ofthepotentiallysupported
modes bythedisplaycontroller. RefertoChapter3foradescriptionofVESAVBEmode numbers.
VBE2.0BIOSimplementationsmust placethis modelist intheReservedareaoftheVbeInfoBlockor
haveitstaticallystoredwithintheVBEimplementationif'VBE2'ispresetintheVbeSignaturefieldon
entrytoFunction00h.
Note: Itisresponsibilityoftheapplicationtoverifytheactualavailabilityofanymodereturnedbythis
functionthroughtheReturnVBEModeInformation(VBEFunction01h)call.Someofthereturned
modesmaynotbeavailableduetotheactualamountofmemoryphysicallyinstalledonthedisplay
boardorduetothecapabilities oftheattachedmonitor.
Note: IfaVideoModeList is foundtocontainnoentries (starts with0FFFFh), it canbeassumed that
theVBEimplementationisa"stub"implementationwhereonlyFunction00hissupportedfordiagnostic
or"PlugandPlay"reasons. Thesestubimplementations arenot VBE2.0compliant andshouldonlybe
implementedincaseswherenospaceisavailabletoimplementtheentireVBE.
The TotalMemoryfieldindicatesthemaximumamountofmemoryphysicallyinstalledandavailableto
the frame buffer in 64KBunits. (e.g. 256KB= 4, 512KB= 8) Not all video modes can address all
thismemory,seetheModeInfoBlockfordetailedinformationabout theaddressablememoryforagiven
mode.
The OemSoftwareRev fieldisaBCDvaluewhichspecifiestheOEMrevisionlevel oftheVBE
software. Thehigherbytespecifiesthemajorversionnumber.Thelowerbytespecifies theminor

VBEFunctions
DOCUMENTREVISION1.1
versionnumber. ThisfieldcanbeusedtoidentifytheOEM's VBEsoftwarerelease. This fieldis only
filledinwhen'VBE2'ispresetintheVbeSignaturefieldonentrytoFunction00h.
The OemVendorNamePtrisapointerto anull-terminatedstringcontainingthenameofthevendor
whichproducedthedisplaycontrollerboardproduct. (This stringmaybecontainedinthe
VbeInfoBlockortheVBEimplementation.) Thisfieldisonlyfilledinwhen'VBE2'ispresetinthe
VbeSignaturefieldonentrytoFunction00h. (Note: thelengthofthestrings OemProductRev,
OemProductNameandOemVendorName(includingterminators)summed,mustfitwithina256byte
buffer;thisistoallowforreturnintheOemDatafieldifnecessary.)
The OemProductNamePtrisapointerto anull-terminatedstringcontainingtheproduct nameofthe
displaycontrollerboard. (ThisstringmaybecontainedintheVbeInfoBlockortheVBE
implementation.) Thisfieldisonlyfilledinwhen'VBE2'ispresetintheVbeSignaturefieldonentryto
Function00h. (Note: thelengthofthestrings OemProductRev, OemProductNameand
OemVendorName(includingterminators)summed,mustfitwithina256bytebuffer;thisistoallowfor
returnintheOemDatafieldifnecessary.)
The OemProductRevPtrisapointertoanull-terminatedstringcontainingtherevisionormanufacturing
levelofthedisplaycontrollerboardproduct. (This stringmaybecontainedintheVbeInfoBlockorthe
VBEimplementation.) Thisfieldcanbeusedtodeterminewhichproductionrevisionofthedisplay
controllerboardisinstalled. Thisfieldisonlyfilledinwhen'VBE2'ispresetintheVbeSignaturefieldon
entrytoFunction00h. (Note: thelengthofthestrings OemProductRev, OemProductNameand
OemVendorName(includingterminators)summed,mustfitwithina256bytebuffer;thisistoallowfor
returnintheOemDatafieldifnecessary.)
The ReservedfieldisaspacereservedfordynamicallybuildingtheVideoModeListifnecessaryifthe
VideoModeListisnotstaticallystoredwithintheVBEimplementation. Thisfieldshouldnotbeusedfor
anythingelse,andmaybereassignedinthefuture. Applicationsoftwareshouldnot assumethat
informationinthisfieldisvalid.
The OemDatafieldis a256bytedataareathat is usedtoreturnOEMinformation returned byVBE
Function00hwhen'VBE2'ispresetintheVbeSignaturefield. TheOemVendorNamestring,
OemProductNamestringandOemProductRevstringarecopiedintothis areabytheVBE
implementation. ThisareawillonlybeusedbyVBEimplementations 2.0andabovewhen'VBE2'is
presetintheVbeSignaturefield.

VBEFunctions
DOCUMENTREVISION1.1
4.4 Function 01h - Return VBE Mode Information
ThisrequiredfunctionreturnsextendedinformationaboutaspecificVBEdisplaymodefromthemode
listreturnedbyVBEFunction00h. Thisfunctionfillsthemodeinformationblock,ModeInfoBlock,
structurewithtechnicaldetailsontherequestedmode. TheModeInfoBlockstructureis providedby
theapplicationwithafixedsizeof256bytes.
InformationcanbeobtainedforalllistedmodesintheVideoModeList returnedinFunction00h. Ifthe
requestedmodecannotbeusedorisunavailable, abit will beset intheModeAttributes fieldtoindicate
thatthemodeisnotsupportedinthecurrentconfiguration.
Input: AX = 4F01h ReturnVBEmodeinformation
CX = Modenumber
ES:DI = PointertoModeInfoBlockstructure
Themodeinformationblockhasthefollowingstructure:
ModeInfoBlockstruc
;MandatoryinformationforallVBErevisions
ModeAttributes dw ? ;modeattributes
WinAAttributes db ? ;windowAattributes
WinBAttributes db ? ;windowBattributes
WinGranularity dw ? ;windowgranularity
WinSize dw ? ;windowsize
WinASegment dw ? ;windowAstart segment
WinBSegment dw ? ;windowBstartsegment
WinFuncPtr dd ? ;pointertowindowfunction
BytesPerScanLine dw ? ;bytes perscanline
;MandatoryinformationforVBE1.2andabove
XResolution dw ? ;horizontalresolutioninpixelsorcharacters3
YResolution dw ? ;verticalresolutioninpixelsorcharacters
XCharSize db ? ;charactercellwidthinpixels
YCharSize db ? ;charactercellheightinpixels
NumberOfPlanes db ? ;numberofmemoryplanes
3
Pixels in graphics modes, characters in text modes.

VBEFunctions
03hReturnCurrentVBE Mode
DOCUMENTREVISION1.1
BitsPerPixel db ? ;bitsperpixel
NumberOfBanks db ? ;numberofbanks
MemoryModel db ? ;memorymodeltype
BankSize db ? ;banksizeinKB
NumberOfImagePages db ? ;numberofimages
Reserved db 1 ;reservedforpagefunction
;DirectColorfields(requiredfordirect/6andYUV/7memorymodels)
RedMaskSize db ? ;sizeofdirect colorredmaskinbits
RedFieldPosition db ? ;bitpositionoflsbofredmask
GreenMaskSize db ? ;sizeofdirectcolorgreenmaskinbits
GreenFieldPosition db ? ;bitpositionoflsbofgreenmask
BlueMaskSize db ? ;sizeofdirectcolorbluemaskinbits
BlueFieldPosition db ? ;bitpositionoflsbofbluemask
RsvdMaskSize db ? ;sizeofdirect colorreservedmaskinbits
RsvdFieldPosition db ? ;bitpositionoflsbofreservedmask
DirectColorModeInfo db ? ;directcolormodeattributes
PhysBasePtr dd ? ;physicaladdressforflatmemoryframebuffer
OffScreenMemOffset dd ? ;pointertostart ofoffscreenmemory
OffScreenMemSize dw ? ;amountofoffscreenmemoryin1kunits
Reserved db 206 dup (?) ; remainderofModeInfoBlock
ModeInfoBlock ends
The ModeAttributes fielddescribescertainimportantcharacteristics ofthegraphics mode.
TheModeAttributesfieldisdefinedasfollows:
D0 = Modesupportedbyhardwareconfiguration
0 = Modenot supportedinhardware
1 = Modesupportedinhardware
D1 = 1(Reserved)
D2 = TTYOutput functions supportedbyBIOS
0 = TTYOutput functions not supportedbyBIOS
1 = TTYOutput functions supportedbyBIOS
D3 = Monochrome/colormode(seenotebelow)
0 = Monochromemode
1= Color mode
D4 = Mode type
0 = Textmode
1 = Graphicsmode
D5 = VGAcompatiblemode
0 = Yes

VBEFunctions
DOCUMENTREVISION1.1
1 = No

VBEFunctions
DOCUMENTREVISION1.1
D6 = VGAcompatiblewindowedmemorymodeisavailable
0 = Yes
1 = No
D7 = Linearframebuffermodeisavailable
0 = No
1 = Yes
D8-D15 = Reserved
BitD0issettoindicatethatthismodecanbeinitializedinthepresenthardwareconfiguration. This bit is
resettoindicatetheunavailabilityofagraphicsmodeifitrequires acertainmonitortype, morememory
thanisphysicallyinstalled,etc.
BitD1wasusedbyVBE1.0and1.1toindicatethat theoptional informationfollowingthe
BytesPerScanLinefieldwerepresentinthedatastructure. Thisinformationbecamemandatorywith
VBEversion1.2andabove, soD1is nolonger used and should be set to 1. The Direct Color fields
arevalidonlyiftheMemoryModel fieldis set toa6(Direct Color)or 7 (YUV).
BitD2indicateswhetherthevideoBIOShassupport foroutput functions likeTTYoutput, scroll, etc.
inthismode. TTYsupport is recommendedbut not requiredforall extendedtext andgraphicmodes.
Ifbit D2is set to1, thentheINT10hBIOSmust support all ofthestandardoutput functions listed
below.
AllofthefollowingTTYfunctionsmustbesupportedwhenthisbitisset:
01 Set CursorSize
02 SetCursorPosition
06 ScrollTTYwindowuporBlankWindow
07 ScrollTTYwindowdownorBlankWindow
09 Writecharacterandattributeat cursorposition
0A Writecharacteronlyat cursorposition
0E Writecharacter and advance cursor
Bit D3is set toindicatecolormodes, andclearedformonochromemodes.
Bit D4is set toindicategraphics modes, andclearedfortext modes.
Note: Monochromemodes maptheir CRTCaddress at 3B4h. Color modes map their CRTCaddress
at3D4h.Monochromemodeshaveattributesinwhichonlybit 3(video)andbit 4(intensity)ofthe
attributecontrolleroutputaresignificant.Therefore,monochrometextmodeshaveattributesofoff,
video,highintensity,blink,etc.Monochromegraphics modes aretwoplanegraphics modes andhave
attributesofoff,video,highintensity,andblink.Extendedtwocolormodes that havetheirCRTC
address at 3D4h, arecolormodes withonebit perpixel and one plane. The standard VGAmodes, 06h
and11h, wouldbeclassifiedas colormodes, whilethestandardVGAmodes 07h and 0Fh would be
classifiedasmonochromemodes.

VBEFunctions
DOCUMENTREVISION1.1
Bit D5is usedtoindicateifthemodeis compatiblewiththeVGAhardwareregisters andI/Oports. If
this bit is set, thenthemodeis NOTVGAcompatibleandnoassumptions shouldbemadeabout the
availabilityofanyVGAregisters. Ifclear, thenthestandardVGAI/Oports andframebufferaddress
definedinWinASegmentand/orWinBSegmentcanbeassumed.
BitD6isusedtoindicateifthemodeprovides WindowingorBankingoftheframebuffer intothe
framebuffermemoryregionspecifiedbyWinASegmentandWinBSegment. Ifset,thenWindowingof
theframebufferis NOTpossible. Ifclear, thenthedeviceis capableof mappingtheframebufferinto
thesegmentspecifiedinWinASegmentand/orWinBSegment. (Thisbitisusedinconjunctionwithbit
D7,seetablefollowingD7forusage).
BitD7indicatesthepresenceofaLinearFrameBuffermemorymodel. Ifthis bit is set, thedisplay
controllercanbeputintoaflatmemorymodelbysettingthemode(VBEFunction02h)withtheFlat
MemoryModelbitset.(ThisbitisusedinconjunctionwithbitD6, seefollowingtableforusage)
D7 D6
Windowed frame buffer only 0 0
n/a 0 1
Both Windowed and Linear
4 1 0
Linear frame buffer only 1 1
The BytesPerScanLine fieldspecifieshowmanyfullbytesareineachlogicalscanline.Thelogical
scanlinecouldbeequaltoorlargerthanthedisplayedscanline.
The WinAAttributes and WinBAttributes describethecharacteristics oftheCPUwindowingscheme
suchaswhetherthewindowsexistandareread/writeable, as follows:
D0 = Relocatablewindow(s)supported
0 = Singlenon-relocatablewindowonly
1 = Relocatablewindow(s)aresupported
D1 = Windowreadable
0 = Windowis not readable
1 = Windowisreadable
D2 = Windowwriteable
0 = Windowisnotwriteable
1 = Windowiswriteable
D3-D7 = Reserved
4
Use D14 of the Mode Number to select the Linear Buffer on a mode set (Function 02h).

VBEFunctions
DOCUMENTREVISION1.1
Evenifwindowingis not supported(bit D0=0forbothWindowAandWindowB), then an
applicationcanassumethatthedisplaymemorybufferresidesatthelocationspecifiedby
WinASegmentand/orWinBSegment.
WinGranularityspecifiesthesmallestboundary, inKB, onwhichthewindowcanbeplacedinthe
framebuffermemory.ThevalueofthisfieldisundefinedifBitD0oftheappropriateWinAttributesfield
is not set.
WinSizespecifiesthesizeofthewindowinKB.
WinASegment and WinBSegmentaddress specifythesegment addresses wherethe windows are
located in the CPUaddress space.
WinFuncPtrspecifiesthesegment:offsetoftheVBEmemorywindowingfunction.Thewindowing
functioncanbeinvokedeitherthroughVBEFunction05h,orbycallingthefunctiondirectly.Adirect
callwillprovidefasteraccesstothehardwarepagingregistersthanusingVBEFunction05h, andis
intendedtobeusedbyhighperformanceapplications.Ifthis fieldis NULL, thenVBEFunction05h
mustbeusedtoset thememorywindowwhenpagingis supported. This direct call methoduses the
sameparametersasVBEFunction05hincludingAXandforVBE2.0implementationswillreturnthe
correct ReturnStatus. VBE1.2implementationsandearlier,didnotrequiretheReturnStatus
informationtobereturned. Formoreinformationonthedirect call method, seethenotes inVBE
Function05handthesamplecodeinAppendix5.
The XResolution and YResolutionspecifythewidthandheightinpixelelementsorcharacters forthis
displaymode.Ingraphicsmodes,thesefieldsindicatethenumberofhorizontalandverticalpixelsthat
maybedisplayed.Intextmodes,thesefieldsindicatethenumberofhorizontal andvertical character
positions. Thenumberofpixelpositionsfortextmodesmaybecalculatedbymultiplyingthereturned
XResolutionandYResolutionvaluesbythecharactercellwidthandheightindicatedintheXCharSize
andYCharSizefieldsdescribedbelow.
The XCharSize and YCharSizespecifythesizeofthecharactercellinpixels. This valueis not zero
based(e.g. XCharSizeforMode3usingthe9point font will haveavalue of9).
The NumberOfPlanes fieldspecifiesthenumberofmemoryplanesavailabletosoftwareinthat mode.
Forstandard16-colorVGAgraphics, this would be set to 4. For standard packed pixel modes, the
fieldwouldbeset to 1. For 256-color non-chain-4 modes, where you need to do bankingto address
allpixels,thisvalueshouldbesettothenumberofbanksrequiredtogettoallthepixels (typicallythis
would be 4 or 8).
The BitsPerPixel fieldspecifiesthetotalnumberofbits allocatedtoonepixel. Forexample, astandard
VGA4Plane16-colorgraphics modewouldhavea4inthis fieldandapacked pixel 256-color
graphicsmodewouldspecify8inthisfield.Thenumberofbits perpixel perplanecannormallybe
derivedbydividingtheBitsPerPixelfieldbytheNumberOfPlanesfield.

VBEFunctions
DOCUMENTREVISION1.1
The MemoryModel fieldspecifiesthegeneraltypeofmemoryorganizationusedinthismode. The
followingmodelshavebeendefined:
00h = Textmode
01h = CGAgraphics
02h = Herculesgraphics
03h = Planar
04h = Packedpixel
05h = Non-chain 4, 256 color
06h = DirectColor
07h = YUV
08h-0Fh = Reserved, to be defined byVESA
10h-FFh = To be defined byOEM
VBEVersion1.1andearlierdefinedDirectColorgraphicsmodes withpixel formats 1:5:5:5, 8:8:8, and
8:8:8:8 as aPackedPixel model with16, 24, and32-bits perpixel, respectively. In VBEVersion 1.2
andlater, theDirect Colormodes usetheDirect Colormemorymodel andusetheMaskSize and
FieldPositionfieldsoftheModeInfoBlocktodescribethepixelformat.BitsPerPixelisalways definedto
bethetotalmemorysizeofthepixel, inbits.
NumberOfBanks.Thisisthenumberofbanksinwhichthescanlines aregrouped. Thequotient from
dividingthescanlinenumberbythenumberofbanksisthebankthatcontains thescanlineandthe
remainderisthescanlinenumberwithinthebank. Forexample, CGAgraphics modes havetwobanks
andHercules graphics modehas fourbanks. Formodes that don't havescanlinebanks (suchas VGA
modes 0Dh-13h), this fieldshouldbeset to 1.
The BankSize fieldspecifies thesizeofabank(groupofscanlines)inunits of1KB. For CGAand
Hercules graphics modes this is 8, as eachbankis 8192bytes inlength. For modes that do not have
scanlinebanks (suchas VGAmodes 0Dh-13h), this fieldshouldbeset to0.
The NumberOfImagePages fieldspecifiesthe"totalnumberminusone(-1)"ofcompletedisplay
imagesthatwillfitintotheframebuffermemory.Theapplicationmayloadmorethanoneimageintothe
framebuffermemoryifthisfieldisnon-zero,andmovethedisplaywindowwithineachofthosepages.
Thisshouldonlybeusedfordeterminingtheadditionaldisplaypageswhichareavailabletothe
application;todeterminetheavailableoffscreenmemory,usetheOffScreenMemOffset and
OffScreenMemSizeinformation.
Note: IftheModeInfoBlockis foranIBMStandardVGAmodeandtheNumberOfImagePages field
containsmorepagesthanwouldbefoundina256KBimplementation, theTTYsupport describedin
theModeAttributes must beaccurate. i.e., iftheTTYfunctions areclaimedtobesupported, theymust
besupportedinallpages,notjustthepagesnormallyfoundinthe256KBimplementation.

VBEFunctions
DOCUMENTREVISION1.1
The Reserved fieldhas beendefinedtosupport afutureVBEfeatureandwill always beset toonein
thisversion.

VBEFunctions
DOCUMENTREVISION1.1
The RedMaskSize, GreenMaskSize, BlueMaskSize, and RsvdMaskSize fieldsdefinethesize,in
bits, ofthered, green, andbluecomponents ofadirect colorpixel. Abit maskcan be constructed from
theMaskSizefieldsusingsimpleshiftarithmetic.Forexample,theMaskSizevaluesforaDirect Color
5:6:5modewouldbe5, 6, 5, and0, forthered, green, blue, and reserved fields, respectively. Note that
intheYUVMemoryModel, theredfieldis usedforV, thegreenfieldis usedforY, andthebluefieldis
usedforU. TheMaskSizefields shouldbeset to0inmodes usingamemorymodel that does not have
pixelswithcomponentfields.
The RedFieldPosition, GreenFieldPosition, BlueFieldPosition, andRsvdFieldPositionfields
definethebitpositionwithinthedirectcolorpixelorYUVpixeloftheleastsignificantbitofthe
respectivecolorcomponent.Acolorvaluecanbealignedwithitspixelfieldbyshiftingthevalueleft by
theFieldPosition.Forexample, theFieldPositionvalues foraDirect Color5:6:5modewouldbe11, 5,
0, and0, forthered, green, blue, andreservedfields, respectively. Note that in the YUV
MemoryModel, theredfieldis usedforV, thegreenfieldis usedforY, andthebluefieldis usedfor U.
TheFieldPositionfieldsshouldbesetto0inmodes usingamemorymodel that does not havepixels
withcomponentfields.
The DirectColorModeInfofielddescribesimportant characteristics ofdirect colormodes. Bit D0
specifieswhetherthecolorrampoftheDACis fixedorprogrammable. Ifthecolorrampis fixed, thenit
cannot bechanged. Ifthecolorrampis programmable, it is assumedthat thered, green, and blue
lookuptablescanbeloadedbyusingVBEFunction09h. Bit D1specifies whetherthebits intheRsvd
fieldofthedirect colorpixel canbeusedbytheapplicationorarereserved, andthus unusable.
D0 = Colorrampisfixed/programmable
0 = Colorrampisfixed
1 = Colorrampisprogrammable
D1 = BitsinRsvdfieldareusable/reserved
0 = BitsinRsvdfieldarereserved
1 = BitsinRsvdfieldareusablebytheapplication
The PhysBasePtrisa32-bitphysical address ofthestart offramebuffermemorywhenthecontroller
isinflatframebuffermemorymode.Ifthismodeisnotavailable,thenthisfieldwillbezero.
The OffScreenMemOffset is a32-bit offset fromthestart oftheframebuffermemory. Extraoff-
screenmemorythat is neededbythecontrollermaybelocatedeitherbeforeorafterthis offscreen
memory,besuretocheckOffScreenMemSizetodeterminetheamount ofoff-screenmemorywhichis
availabletotheapplication.
The OffScreenMemSize containstheamountofavailable,contiguousoff-screenmemoryin1kunits,
whichcanbeusedbytheapplication.

VBEFunctions
DOCUMENTREVISION1.1
Note: Version1.1andlaterVBEwillzerooutallunusedfieldsintheModeInformationBlock, always
returningexactly256bytes.Thisfacilitatesupwardcompatibilitywithfutureversionsofthestandard,as
anynewlyaddedfieldswillbedesignedsuchthatvaluesofzerowillindicatenominaldefaultsornon-
implementationofoptionalfeatures.(Forexample,afieldcontainingabit-maskofextendedcapabilities
wouldreflecttheabsenceofallsuchcapabilities.)Applications that wishtobebackwards compatibleto
Version1.0VBEshouldpre-initializethe256bytebufferbeforecallingtheReturnVBEMode
Informationfunction.
4.5 Function 02h - Set VBE Mode
ThisrequiredfunctioninitializesthecontrollerandsetsaVBEmode. Theformat ofVESAVBEmode
numbersisdescribedearlierinthis document. Ifthemodecannot beset, theBIOSshouldleavethe
graphicsenvironmentunchangedandreturnafailureerrorcode.
Input: AX = 4F02h Set VBEMode
BX = Desired Mode to set
D0-D8= Modenumber
D9-D13 = Reserved(must be 0)
D14 = 0 Usewindowedframebuffermodel
= 1 Uselinear/flatframebuffermodel
D15 = 0 Cleardisplaymemory
= 1 Don'tcleardisplaymemory
Iftherequestedmodenumberisnotavailable,thenthecallwillfail,returningAH=01htoindicatethe
failuretotheapplication.
IfbitD14isset,themodewill beinitializedforusewithaflat framebuffermodel. Thebaseaddress of
theframebuffercanbedeterminedfromtheextendedmodeinformationreturnedbyVBEFunction
01h. IfD14isset,andalinearframebuffermodelisnotavailablethenthecall will fail.
IfbitD15isnotset,all reportedimagepages, basedonFunction00hreturnedinformation
NumberOfImagePages, will beclearedto00hingraphics mode, and20 07 in text mode. Memory
overandabovethereportedimagepages will not bechanged. Ifbit D15is set, then the contents ofthe
framebufferafterthemodechangeis undefined. Note, the1-bytemodenumbers usedinFunction00h
ofanIBMVGAcompatibleBIOSuseD7tosignifythesamethingas D15does inthis function. If
functioncallD7issetandtheapplicationassumesitissimilartotheIBMcompatiblemodeset using
VBEFunction02h,theimplementationwillfail. VBEawareapplicationsmustusethememoryclearbit
inD15.

VBEFunctions
DOCUMENTREVISION1.1
Note: VBEBIOS2.0implementations shouldalsoupdatetheBIOSDataArea40:87memoryclear
bitsothatVBEFunction03hcanreturnthisflag.VBEBIOS1.2andearlierimplementations ignorethe
memoryclearbit.
Note: Thiscallshouldnotsetmodesnot listedinthelist ofsupportedmodes. Inadditionall modes
(includingIBMstandardVGAmodes),iflistedassupported,must haveModeInfoBlockstructures
associatedwiththem. RequiredModeInfoBlockvalues fortheIBMStandardModes arelistedin
Appendix2.
4.6 Function 03h - Return Current VBE Mode
ThisrequiredfunctionreturnsthecurrentVBEmode. Theformat ofVBEmodenumbers is described
earlierinthisdocument.
Input: AX = 4F03h Returncurrent VBEMode
BX = CurrentVBEmode
D0-D13 = Modenumber
D14 = 0 Windowedframebuffermodel
= 1 Linear/flatframebuffermodel
D15 = 0 Memoryclearedat last mode set
= 1 Memorynot clearedat last mode set
Version 1.x Note: InastandardVGABIOS, Function0Fh(Readcurrent video state) returns the
currentgraphics modeintheALregister. InD7ofAL, it alsoreturns thestatus ofthememoryclearbit
(D7of40:87).Thisbitissetifthemodewassetwithoutclearingmemory. Inthis VBEfunction, the
memoryclearbitwillnotbereturnedinBXsincethepurposeofthefunctionis toreturnthevideomode
only.Ifanapplicationwantstoobtainthememoryclearbit, it shouldcall thestandardVGABIOS
Function0Fh.
Version 2.x Note: Unlikeversion1.xVBEimplementations,thememoryclearflagwillbereturned.
TheapplicationshouldNOTcall thestandardVGABIOSFunction0Fhifthemodewas set withVBE
Function02h.
Note: Themodenumberreturnedmust bethesamemodenumberusedintheVBEFunction02hmode
set.
Note: Thisfunctionis not guaranteedtoreturnanaccuratemodevalueifthemodeset was not done
withVBEFunction02h.

VBEFunctions
07hSet/GetDisplayStart
DOCUMENTREVISION1.1
4.7 Function 04h - Save/Restore State
Thisrequiredfunctionprovidesacompletemechanismtosaveandrestorethedisplaycontroller
hardwarestate. Thefunctions areasuperset ofthethreesubfunctions underthestandardVGABIOS
Function1Ch(Save/restorestate)whichdoes not guaranteethat theextendedregisters ofthevideo
devicearesavedorrestored. Thecompletehardwarestate(except framebuffermemory)should be
saveable/restorablebysettingtherequestedstates mask(intheCXregister)to000Fh.
Input: AX = 4F04h Save/RestoreState
DL = 00h ReturnSave/RestoreStatebuffersize
= 01h Savestate
= 02h Restorestate
CX = Requestedstates
D0= Save/Restorecontrollerhardwarestate
D1= Save/Restore BIOSdata state
D2= Save/RestoreDACstate
D3= Save/RestoreRegisterstate
ES:BX = Pointertobuffer (ifDL<> 00h)
BX = Numberof64-byte blocks to hold the state
buffer (ifDL=00h)
4.8 Function 05h - Display Window Control
Thisrequiredfunctionsetsorgetsthepositionofthespecifieddisplaywindoworpageintheframe
buffermemorybyadjustingthenecessaryhardwarepagingregisters. Tousethis functionproperly, the
softwareshouldfirstuseVBEFunction01h(ReturnVBEModeinformation)todeterminethesize,
locationandgranularityofthewindows.
Forperformancereasons,itmaybemoreefficienttocallthisfunctiondirectly,withoutincurringtheINT
10hoverhead. VBEFunction01hreturnsthesegment:offsetofthiswindowingfunctionthatmaybe
calleddirectlyforthis reason. Notethat adifferent entrypoint maybereturnedbasedupontheselected
mode. Therefore,itisnecessarytoretrievethissegment:offset specificallyforeachdesiredmode.
Input: AX = 4F05h VBEDisplayWindowControl
BH = 00h Setmemorywindow
= 01h Getmemorywindow
BL = Windownumber
= 00h WindowA
= 01h WindowB
DX = Windownumberinvideomemoryinwindow
granularityunits (SetMemoryWindowonly)

VBEFunctions
DOCUMENTREVISION1.1
DX = Windownumberinwindowgranularityunits
(GetMemoryWindowonly)
Note: InVBE1.2implementations,thedirectfarcallversionreturnsnoReturnStatusinformationto
theapplication.Also,inthefarcallversion, theAXandDXregisters will bedestroyed. ThereforeifAX
and/orDXmustbepreserved, theapplicationmust dosopriortomakingthefarcall. Theapplication
muststillloadtheinputargumentsinBH,BL,andDX(forSet Window). InVBE2.0implementations,
theBIOSwillreturnthecorrectReturnStatus, andthereforetheapplicationmust assumethat AXand
DXwill bedestroyed.
Application Developer's Note: Thisfunctionisnotintendedforuseinalinearframebuffermode, if
thisfunctionisrequested,thefunctioncallwillfailwiththeVBECompletioncodeAH=03h.
VBEBIOSImplementationNote: Ifthisfunctioniscalledwhileinalinearframebuffermemory
model,thisfunctionmustfailwithcompletioncodeAH=03h.
4.9 Function 06h - Set/Get Logical Scan Line Length
Thisrequiredfunctionsetsorgetsthelengthofalogicalscanline.This allows anapplicationtoset upa
logicaldisplaymemorybufferthatiswiderthanthedisplayedarea.VBEFunction07h(Set/Get Display
Start)thenallowstheapplicationtosetthestartingpositionthat is tobedisplayed.
Input: AX = 4F06h VBESet/GetLogicalScanLineLength
BL = 00h SetScanLineLengthinPixels
= 01h GetScanLineLength
= 02h SetScanLineLengthinBytes
= 03h GetMaximumScanLineLength
CX = IfBL=00h DesiredWidthinPixels
IfBL=02h DesiredWidthinBytes
(IgnoredforGetFunctions
BX = Bytes PerScan Line
CX = ActualPixelsPerScanLine
(truncatedtonearestcompletepixel)
DX = MaximumNumberofScanLines
Note: Thedesiredwidthinpixels orbytes maynot beachievablebecauseofhardwareconsiderations.
Thenextlargervaluewillbeselectedthatwillaccommodatethedesirednumberofpixels orbytes, and
theactualnumberofpixelswill bereturnedinCX. BXreturns avaluethat whenaddedtoapointerinto
displaymemorywillpointtothenextscanline. Forexample, inVGAmode13hthis wouldbe320, but
inmode12hthis wouldbe80. DXreturns thenumberoflogical scanlines baseduponthenewscan
linelengthandthetotalmemoryinstalledandusableinthisdisplaymode.

VBEFunctions
07hSet/GetDisplayStart
DOCUMENTREVISION1.1
Note: Thisfunctionis alsovalidinVBEsupportedtext modes. InVBEsupportedtext modes the
applicationshouldconvertthecharacterlinelengthtopixellinelengthbygettingthecurrentcharacter
cellwidththroughtheXCharSizefieldreturnedinModeInfoBlock,multiplyingthattimesthedesired
numberofcharactersperline,andpassingthatvalueintheCXregister. Inaddition,this functionwill
onlyworkifthelinelengthisspecifiedincharactergranularity. i.e.in8dotmodesonlymultiples of8
willwork. Anyvaluewhichisnotincharactergranularitywillresultinafunctioncallfailure.
Note: OnafailuretosetscanlinelengthbysettingaCXvaluetoolarge, thefunctionwill fail witherror
code02h.
Note: ThevaluereturnedwhenBL=03histhelesserofeitherthemaximumlinelengththat the
hardwarecansupport,orthelongestscanlinelengththat wouldsupport thenumberoflines inthe
currentvideomode.
4.10 Function 07h - Set/Get Display Start
Thisrequiredfunctionselectsthepixeltobedisplayedintheupperleft cornerofthedisplay. This
functioncanbeusedtopanandscroll aroundlogical screens that arelargerthanthedisplayedscreen.
Thisfunctioncanalsobeusedtorapidlyswitchbetweentwodifferent displayedscreens fordouble
bufferedanimationeffects.
Input: AX = 4F07h VBESet/Get DisplayStart Control
BH = 00h Reservedandmust be 00h
BL = 00h SetDisplayStart
= 01h GetDisplayStart
= 80h SetDisplayStartduringVertical Retrace
CX = FirstDisplayedPixelInScanLine
(SetDisplayStartonly)
DX = FirstDisplayedScanLine(Set DisplayStart only)
BH = 00hReservedandwill be0(Get DisplayStart only)
CX = FirstDisplayedPixelInScanLine(Get DisplayStart only)
DX = FirstDisplayedScanLine(Get DisplayStart only)
Note: Thisfunctionisalsovalidintextmodes. Tousethisfunctionintextmode,theapplicationshould
convertthecharactercoordinatestopixelcoordinatesbyusingXCharSizeandYCharSizereturnedin
theModeInfoBlock. IftherequestedDisplayStart coordinates donot allowforafull pageofvideo
memoryorthehardwaredoesnotsupportmemorywrapping, theFunctioncall shouldfail andno
changes shouldbemade. As ageneral case, ifarequestedDisplayStart is not available, fail the
Functioncallandmakenochanges.
Note: CX and DX,forbothinputandoutput values,will bezero-based.

VBEFunctions
0AhReturnVBE Protected Mode Interface
DOCUMENTREVISION1.1
4.11 Function 08h - Set/Get DAC Palette Format
Thisrequiredfunctionmanipulates theoperatingmodeorformat oftheDACpalette. SomeDACs are
configurabletoprovide6bits, 8bits, ormoreofcolordefinitionperred, green, andblueprimary
colors. TheDACpalettewidthis assumedtobereset tothe standard VGAvalue of6 bits per primary
colorduringanymodeset.
Input: AX = 4F08h VBESet/Get PaletteFormat
BL = 00h Set DACPalette Format
= 01h Get DACPaletteFormat
BH = Desiredbits ofcolorperprimary
(Set DACPalette Format only)
BH = Currentnumberofbits ofcolorperprimary
AnapplicationcandetermineifDACswitchingisavailablebyqueryingBitD0oftheCapabilitiesfield
oftheVbeInfoBlockstructurereturnedbyVBEFunction00h(ReturnControllerInformation). The
applicationcanthenattempttosettheDACpalettewidthtothedesiredvalue. Ifthedisplaycontroller
hardwareisnotcapableofselectingtherequestedpalettewidth, thenthenext lowervaluethat the
hardwareis capableofwill beselected. Theresultingpalettewidthisreturned.
ThisfunctionwillreturnfailurecodeAH=03hifcalledinadirect colororYUVmode.
4.12 Function 09h - Set/Get Palette Data
ThisrequiredfunctionisveryimportantforRAMDAC's whicharelargerthanastandardVGA
RAMDAC. ThestandardINT10hBIOSPalettefunctioncalls assume standard VGAports and VGA
palettewidths. ThisfunctionoffersapaletteinterfacethatisindependentoftheVGAassumptions.
Input: AX = 4F09h VBELoad/UnloadPaletteData
BL = 00h Set PaletteData
= 01h Get PaletteData
= 02h Set SecondaryPalette Data
= 03h Get SecondaryPaletteData
= 80h SetPaletteDataduringVertical Retrace
withBlankBit on
CX = Numberofpaletteregisters to update (to a
maximumof256)
DX = First ofthepaletteregisters toupdate(start)
ES:DI = Tableofpalettevalues (seebelowforformat)

VBEFunctions
0AhReturn VBE Protected Mode Interface
DOCUMENTREVISION1.1
Format of Palette Values:Alignment byte, Red byte, Green byte, Blue byte
Note: TheneedforBL=80his forolderstyleRAMDAC's whereprogrammingtheRAMvalues
duringdisplaytimecausesa"snow-like"effect onthescreen. NewerstyleRAMDAC's don't havethis
limitationandcaneasilybeprogrammedat anytime, but olderRAMDAC's requirethat theybe
programmedduringanon-displaytimeonlytostopthesnowlikeeffect seenwhenchangingtheDAC
values. WhenthisisrequestedtheVBEimplementationwillprogramtheDACwithblankingon.
CheckD2oftheCapabilitiesfieldreturnedbyVBEFunction00htodetermineif80hshouldbeused
insteadof00h.
Note: Theneedforthesecondarypaletteis foranticipatedfuturepaletteextensions, ifasecondary
palettedoesnotexistinaimplementationandthesecallsaremade,theVBEimplementationwillreturn
error code 02h.
Note: Whenin6bit mode, theformat ofthe 6 bits is LSB, this is done for speed reasons, as the
applicationcantypicallyshiftthedatafasterthantheBIOScan.
Note: AllapplicationshouldassumetheDACisdefaultedto6bit mode. Theapplicationis responsible
forswitchingtheDACtohighercolormodesusingFunction08h.
Note: QueryVBEFunction08htodeterminetheRAMDACwidthbeforeloadinganewpalette.
4.13 Function 0Ah - Return VBE Protected Mode Interface
Thisrequiredfunctioncall returns apointertoatablethat contains codefora32-bit protectedmode
interfacethat caneitherbecopiedintolocal 32-bit memoryspaceorcan be executed fromROM
providingthecallingapplicationsetsallrequiredselectorsandI/Oaccesscorrectly.Thisfunctionreturns
apointer(inrealmodespace)withoffsets tothecodefragments, andadditionallyreturns anoffset toa
tablewhichcontainsNon-VGAPortandMemorylocations whichanApplicationmayhavetohaveI/O
access to.
Input: AX = 4F0Ah VBE2.0 Protected Mode Interface
BL = 00h Returnprotectedmodetable
Output: AX = Status
ES = Real ModeSegment ofTable
DI = OffsetofTable
CX = LengthofTableincludingprotectedmodecodein bytes
(forcopyingpurposes)

VBEFunctions
0AhReturnVBE Protected Mode Interface
DOCUMENTREVISION1.1
Theformatofthetableisasfollows:
ES:DI+ 00h WordOffset in table ofProtected mode code for
Function5forSet WindowCall
Function7forset DisplayStart
Function9forset PrimaryPalettedata
ES:DI+ 06h Word Offset intableofPorts and MemoryLocations
thattheapplicationmayneedI/Oprivilegefor.
(Optional: ifunsupportedthismustbe0000h)
(SeeSub-tableforformat)
ES:DI + ? VariableremainderofTableincludingCode
Theformat oftheSub-Table(Ports andMemorylocations)
Port, Port, ... , Port, Terminate Port List with FFFF, Memorylocations (4 bytes), Length (2
bytes), TerminateMemoryList withFFFF.
Example 1.ForPort/Indexcombination3DE/FhandMemorylocations DE800-DEA00h(length =
200h)thetablewouldlooklikethis:
DE 03 DF 03 FF FF 00 E8 0D 00 00 02 FF FF
Example 2.Foronlytheports it wouldlooklike:
DE 03 DF 03 FF FF FF FF
Example 3.Foronlythememorylocationsitwouldlooklike
FF FF 00 E8 0D 00 00 02 FF FF
Note:. All protectedmodefunctions shouldendwithanearRET(as opposedtoFARRET)to allow
theapplicationsoftwaretoCALLthecodefromwithintheROM.
Note: ThePort andMemorylocationSub-tabledoes not includetheFrameBufferMemorylocation.
TheFrameBufferMemorylocationiscontainedwithintheModeInfoBlockreturnedbyVBEFunction
01h.
Note: Theprotectedmodecodeis assembled for a 32-bit code segment, when copyingit, the
applicationmust copythecodetoa32-bit code segment.
Note: Itistheresponsibilityoftheapplicationtoensurethat theselectors andsegments areset up
correctly.

VBEFunctions
0AhReturn VBE Protected Mode Interface
DOCUMENTREVISION1.1
Ifthememorylocationis zero, thenonlyI/Omappedports will beusedsotheapplicationdoes not
needtodoanythingspecial. This shouldbethedefault caseforALLcards that have I/Omapped
registersbecauseit provides thebest performance.
Ifthememorylocationis nonzero(therecanbeonlyone), theapplication will need to create a new32-
bitselectorwiththebaseaddressthatpointstothe“physical”locationspecifiedwiththespecifiedlimit.
Whentheapplicationneedstocallthe32-bit bankswitchfunction, it must thenloadtheESselector
withthevalueofthenewselectorthat has beencreated. Thebankswitchingcodecanthendirectly
accessitsmemorymappedregisters as absoluteoffsets intotheESselector
(i.e., mov[es:10],eaxtoput avalueintotheregisterat base+10).
It is uptotheapplicationcodetosaveandrestoretheprevious stateofthe ESselector ifthis is
necessary(forexampleinflat model code).
Note: Currentlyundefinedregisters maybedestroyedwiththeexceptionofESI, EBP, DSand SS.
Note: Applicationsmustusethesameregisters fortheFunction05handFunction09hprotectedmode
interfacethatitwoulduseinarealmodecall. This includes theAXregister.
Note: Function07hprotectedmodecalls haveadifferent format.
AX = 4F07h
BL = 00h Set DisplayCRTCStart
= 80h SetDisplayCRTCStart duringVertical Retrace
CX = Bits 0-15ofdisplaystart address
DX = Bits 16-31ofdisplaystart address
Theprotectedmodeapplicationmust keeptrackofthecolordepthandscanlinelengthtocalculatethe
newstartaddress. Ifavaluethat is out ofrangeis programmed, unpredictableresults will occur.
Note: RefertoSection4.2forinformationonprotectedmodeconsiderations.

VBESupplementalSpecifications
DOCUMENTREVISION1.1
5.0 VBE Supplemental Specifications
ThischapterdetailsVBESupplementalSpecifications.
5.1 Purpose of Supplemental Specifications
TheVBEwasoriginallydesignedtoprovideadevice-independentinterfacebetweenapplication
softwareandSVGAhardware.Inthelastfewyears, thepersonal computingenvironment has grown
muchmorecomplexandtherehavebeennumerous requests toprovideinterfaces similartotheVBEto
servicethesenewrequirements.TheVBEsupplementalspecificationarchitectureprovides awayto
extendthebasicVBEspecificationwithoutmakingittoounwieldyorhavingtorevisetheVBE
specificationitself.
ThesupplementalspecificationsareimplementedusingVBEfunctionnumbersstartingatAL=10h.This
leavesthefirstsixteenfunctionsavailableforeventualVBEgrowth.Individualcallsforeach
supplementalspecificationaremadethroughasubfunctionnumberviatheBLregister.This
function/subfunctionarchitectureiscompatiblewiththeVBEandprovideseachVBESupplemental
Specificationwith64potentialsubfunctions.Subfunction00hforeachsupplementalspecificationis
reservedfora'ReturnVBESupplementalSpecificationInformation'call. It is basedontheVBE
Function00handreturnsbasicinformationontheVBESupplementalSpecificationimplementation.
5.2 Obtaining Supplemental VBE Function Numbers
VBESupplemental Specifications canonlybecreatedbyVESAcommittees. Onceaneedforanew
softwarespecificationhasbeenidentified,thegroupworkingonit needs tocontact theVESASoftware
StandardsCommittee(SSC)todiscusstherequirements. TheSSCwill assignafunctionnumberand
nametothesupplementalspecification.Thenameassignedtoasupplementalspecificationwillbeinthe
formof'VBE/???'wherethe'???'is atwoorthreeletteracronymforits function. Twoletteracronyms
will bepaddedwithFFhforthethirdletter. Insomecases thecommitteethat is workingonthe
supplementalspecificationmayhaveanothernamethattheywilluseforpromotionalpurposes,however
theVBE/???willcontinuetobethesignature.
TheVBEspecificationwillberevisedperiodicallytoupdatethelistofsupplementalspecifications. To
obtaintheactualspecifications,contacttheVESAoffice.

DOCUMENTREVISION1.1
5.3 Required VBE Supplemental Specification Components
5.3.1 VBE Supplemental Specification Functions
AllVBESupplementalSpecificationfunctionsarecalledwiththeAHregistersetto4Fhtoidentifythem
asVBEfunctioncalls. TheALregisterisusedtospecifywhichVESAfunctionthesupplemental
specificationisusing. TheBLregisterwillcontainthesubfunctionnumberforthecallbeingmade,BH
willcontainthesub-subfunctionnumberifnecessary.
e.g.,Input: AX =4FXXh VESASupplementalVBESpecification
('XX'representsthefunctionnumberforthe
supplementalspecification)
BL = ? Subfunction
BH = ? Sub-subfunction
5.3.2 Return Status
AllVBESupplementalSpecificationswillusetheVBECompletioncodesasdocumentedinSection4.1
oftheVBEspecification.
5.3.3 Subfunction 00h - Return VBE Supplemental Specification Information
Thissubfunctionreturnsthecapabilities,revisionlevel,andvendorspecificinformationofthe
supplementalspecification,andisarequiredfunctionforanyVBE2.xSupplementalSpecification.
Thepurposeofthissubfunctionistoprovideinformationtothecallingprogramaboutthegeneral
capabilitiesoftheinstalledVBEsoftwareandhardware. Thissubfunctionfillsaninformationblock
structureattheaddressspecifiedbythecaller. TheSupVBEInfoBlockinformationblocksizeis 256
bytes.
Input: AX =4FXXh ReturnSupplementalVBESpecificationInformation
('XX'representsthefunctionnumberforthe
supplementalspecification)
BL = 00h Subfunction'0'
SupVBEInfoBlockstructure
Output:AX = VBEReturnStatus
Otherregistersmaybedefinedforinputandoutput basedupontheparticularrequirements of
supplementalspecifications
Whenwritingsupplementalfunctions,explicitlystatewhichregistersarepreservedandwhichare
destroyed. Refrainfrompreservingallregistersasthistendstolimitexpandabilityinthefuture. An
exampleofthenoteis:

DOCUMENTREVISION1.1
Note: Currentlyundefinedregisters maybedestroyedwiththeexceptionof SI,BP,DS
and SS.
Theinformationblockhasthefollowingstructure:
SupVbeInfoBlockstruc
SupVbeSignature db 'VBE/???' ;SupplementalVBESignature
SupVbeVersion dw ? ;SupplementalVBEVersion
SupVbeSubFunc db 8dup (?) ;Bitfieldofsupportedsubfunctions
OemSoftwareRev dw ? ;OEMSoftwarerevision
OemProductNamePtr dd ? ;PointertoProduct NameString
Reserved db 221 dup (?) ;Reservedfordescriptionstringsandfuture
;expansion
SupVbeInfoBlockends
Note: AlldatainthisstructureissubjecttochangebytheVBEimplementationwhenanyVBE
Subfunction00hiscalled. Thereforeit shouldnot beusedbytheapplicationtostoredataofanykind.
Descriptionofthe SupVbeInfoBlockstructurefields:
The SupVbeSignaturefieldisfilledwiththeASCIIcharacters 'VBE/'followedbythetwoorthree
letteracronymthatrepresentsthesupplementalspecification.Thisfieldisfilledbythesupplementary
VBEimplementation. Intheeventthattheacronymisonlytwoletters,thethirdlettermustbefilledwith
FFh.
The SupVbeVersionisaBCDvaluewhichspecifieswhatleveloftheVBEsupplementary
specificationisimplementedinthesoftware.Thehigherbytespecifiesthemajorversionnumber.The
lowerbytespecifiestheminorversionnumber.
Note: The BCDvalue for 2.0 is 0200h and the BCDvalue for 1.2 is 0102h. In the past we have had
someapplicationsmisinterpretingtheseBCDvalues. Forexample, BCD0102hwas interpretedas
1.02,whichisincorrect.
The SupVbeSubFuncisabitfieldthatrepresentsthesubfunctionsavailableforthesupplementary
specification.Ifthebitrepresentingaparticularsubfunctionisset,thenthatsubfunctionissupported.
Subfunction'0'isrepresentedbytheLSBofthefirst byteandtheothersubfunctions follow. Onlybits
forsubfunctionsdefinedinthespecificationneedtobeset.
The OemStringPtrisaRealModefarpointertoanull-terminatedOEM-definedstring. This stringmay
usedtoidentifythegraphicscontrollerchiporOEMproductfamilyforhardwarespecificdisplay

DOCUMENTREVISION1.1
drivers.Therearenorestrictionsontheformat ofthestring. This pointermaypoint intoeitherROMor
RAM,dependingonthespecificimplementation.

DOCUMENTREVISION1.1
The OemSoftwareRev fieldisaBCDvaluewhichspecifiestheOEMrevisionlevel ofthe
SupplementalSpecificationsoftware. Thehigherbytespecifiesthemajorversionnumber.Thelower
bytespecifiestheminorversionnumber. This fieldcanbeusedtoidentifytheOEM's VBEsoftware
release.
The OemVendorNamePtrisaRealModefarpointertoanull-terminatedOEM-definedstring
containingthenameofthevendorwhoproducedthedisplaycontrollerboardproduct.
The OemProductNamePtrisaRealModefarpointertoanull-terminatedOEM-definedstring
containingtheproductnameofthedisplaycontrollerboard.
The OemProductRevPtrisaRealModefarpointertoanull-terminatedOEM-definedstring
containingtherevisionormanufacturinglevelofthedisplaycontrollerboardproduct. Thisfieldcanbe
usedtodeterminewhichproductionrevisionofthedisplaycontrollerboardisinstalled.
5.4 Supplemental Specification Protected Mode Guidelines
VBESupplementalSpecificationsmaywishtoincorporate32-bit protectedmodeinterfaces based
uponthe32-bitprotectedmodeinterfaceinVBE2.0. Theguidelines forthis aresimple.
Input: AX =4FXXh SupplementalSpecificationFunctionNumber
BL = XX Return32-bit protectedmodeinterfacetable
Output: AX = Status
DI = OffsetofTable
CX = LengthofTableincludingprotectedmodecode
Theformatofthetableshouldbeas follows:
firstfunction
ES:DI+(n*2) WordOffset in table ofProtected mode code for
nthfunction
ES:DI+ ? Word Offset intableofPorts and MemoryLocations
thattheapplicationmayneedI/Oprivilegefor
(Optional: ifunsupportedthismustbe0000h)
(SeeSub-tableforformat)
ES:DI + ? VariableremainderofTableincludingCode

DOCUMENTREVISION1.1
Theformat oftheSub-Table(Ports andMemorylocations)
Port, Port, ... , Port, Terminate Port List with FFFF, Memorylocations (4 bytes), Length (2
bytes), TerminateMemoryList withFFFF.
Example 1.ForPort/Indexcombination3DE/FhandMemorylocations DE800-DEA00h(length=
200h)thetablewouldlooklikethis:
DE 03 DF 03 FF FF 00 E8 0D 00 00 02 FF FF
Example 2.Foronlytheports it wouldlooklike:
DE 03 DF 03 FF FF FF FF
Example 3.Foronlythememorylocationsitwouldlooklike
FF FF 00 E8 0D 00 00 02 FF FF
Note:. All protectedmodefunctions shouldendwithanearRET(as opposedtoFARRET)to allow
theapplicationsoftwaretoCALLthecodefromwithintheROM.
Note: Theprotectedmodecodeshouldbeassembled for a 32-bit code segment, when copyingit, the
applicationmust copythecodetoa32-bit code segment.
Note: Itistheresponsibilityoftheapplicationtoensurethat theselectors andsegments areset up
correctly.
Note: Currentlyundefinedregisters maybedestroyedwiththeexceptionofESI, EBP, DSand SS.
Indevelopingasupplementalspecification,ensurethatboththeapplicationdeveloperandthe
VBE/XXXimplementorsareawareofwhichportionofthefunctionissupported, i.e., ifafunction
supports bothaGet andaSet function, spell out whichis supported, the Get, the Set or both.
5.5 Loading Supplemental Drivers
VBESupplementalSpecificationscanbeimplementedinROM, TSRprograms oras devicedrivers.
Thespecificrequirementswillvarydependingontheindividualsupplementaryspecification.Ifthereare
anyspecificrequirements,theyshouldbedetailedinthesupplementaryspecification.
5.6 Implementation Questions
Whendevelopinganewsupplementalspecification,implementationquestionswhethertheyarecovered
inthisguidelineornot,shouldbereferredtotheVESASoftwareStandards Committeeforclarification.
ThechairmanoftheSSCcanbecontactedthroughVESAoffice.

DOCUMENTREVISION1.1
5.7 Known Supplemental Specifications
5.7.1 Function 10h - Power Management Extensions (PM)
Thisoptionalfunctioncontrolsthepowerstateoftheattacheddisplaydeviceormonitor.
RefertotheVBE/PMStandardforspecifics.
5.7.2 Function 11h - Flat Panel Interface Extensions (FP)
Thisproposedoptionalsupplementalspecificationallowsaccesstothespecialfeatures incorporatedin
FlatPanelcontrollers.Thereisnoreferencespecificationat thetimeofthis standard's approval. Contact
theVESAofficeformoreinformation.
5.7.3 Function 12h - Cursor Interface Extensions (CI)
ThisproposedoptionalfunctionprovidesservicesforHardwareCursors andPointingDevices. At this
time,thisisindevelopment. Thereisnoreferencespecificationat thetimeofthis standard's approval,
contacttheVESAofficeformoreinformation.
5.7.4 Function 13h - Audio Interface Extensions (AI)
ThisoptionalfunctionprovidesstandardAudioservices.
RefertotheVBE/AIStandardforspecifics.
5.7.5 Function 14h - OEM Extensions
ThisoptionalsupplementalfunctionprovidesOEM'swithacodedispatchareathat falls underthe
VESA4Fhfunctions. AnOEMmayusethis areaat theirown risk. VESAstates no warranties or
guaranteesaboutthefunctioncallscontainedwithinthisarea.
5.7.6 Function 15h - Display Data Channel (DDC)
Thisoptionalfunctionprovidesamechanismtoextractdatafromattacheddisplaydevices ontheVESA
communicationchannel. RefertotheVBE/DDCStandardforspecifics.
5.7.7 Function 16h - Graphics System Configuration (GC)
Thisproposedsupplementalfunctionprovidesamechanismforsystemlevelservicestoset upMonitor
Timings,LinearFrameBufferaddressesetc.,i.e.systemlevelcallsthatapplicationsshouldnot deal with
. Thereisnoreferencespecificationat thetimeofthis standard's approval. Contact theVESAoffice
formoreinformation.

VBEQuickReference
DOCUMENTREVISION1.1
Appendix 1 - VBE Quick Reference
Input: AX = 4F00h ReturnVBEControllerInformation
VbeInfoBlockstructure
(VbeSignatureshouldbeset to'VBE2'when
functioniscalledtoindicateVBE2.0information
isdesiredandtheinformationblockis 512bytes in
size.)
______________________________
Input: AX = 4F01h ReturnVBEmodeinformation
CX = Modenumber
ES:DI = PointertoModeInfoBlockstructure
______________________________
Input: AX = 4F02h Set VBEMode
BX = Desired Mode to set
D0-D8= Modenumber
D9-D13 = Reserved(must be 0)
D14 = 0 Usewindowedframebuffermodel
= 1 Uselinear/flatframebuffermodel
D15 = 0 Cleardisplaymemory
= 1 Don'tcleardisplaymemory
______________________________

VBEQuickReference
DOCUMENTREVISION1.1
Input: AX = 4F03h Returncurrent VBEMode
BX = CurrentVBEmode
D0-D13 = Modenumber
D14 = 0 Windowedframebuffermodel
= 1 Linear/flatframebuffermodel
D15 = 0 Memoryclearedat last mode set
= 1 Memorynot clearedat last mode set
______________________________
Input: AX = 4F04h Save/RestoreState
DL = 00h ReturnSave/RestoreStatebuffersize
= 01h Savestate
= 02h Restorestate
CX = Requestedstates
D0= Save/Restorecontrollerhardwarestate
D1= Save/Restore BIOSdata state
D2= Save/RestoreDACstate
D3= Save/RestoreRegisterstate
ES:BX = Pointertobuffer (ifDL <> 00h)
BX = Numberof64-byte blocks to hold the state
buffer (ifDL=00h)
______________________________
Input: AX = 4F05h VBEDisplayWindowControl
BH = 00h Setmemorywindow
= 01h Getmemorywindow
BL = Windownumber
= 00h WindowA
= 01h WindowB
DX = Windownumberinvideomemoryinwindow
granularityunits (SetMemoryWindowonly)
DX = Windownumberinwindowgranularityunits

VBEQuickReference
DOCUMENTREVISION1.1
______________________________

VBEQuickReference
DOCUMENTREVISION1.1
Input: AX = 4F06h VBESet/GetLogicalScanLineLength
BL = 00h SetScanLineLengthinPixels
= 01h GetScanLineLength
= 02h SetScanLineLengthinBytes
= 03h GetMaximumScanLineLength
CX = IfBL=00h DesiredWidthinPixels
IfBL=02h DesiredWidthinBytes
(IgnoredforGetFunctions)
BX = Bytes PerScan Line
CX = ActualPixels PerScanLine
(truncatedtonearestcompletepixel)
DX = MaximumNumberofScanLines
______________________________
Input: AX = 4F07h VBESet/Get DisplayStart Control
BH = 00h Reservedandmust be 00h
BL = 00h SetDisplayStart
= 01h GetDisplayStart
= 80h SetDisplayStartduringVertical Retrace
CX = FirstDisplayedPixelInScanLine
(SetDisplayStartonly)
DX = FirstDisplayedScanLine(Set DisplayStart only)
BH = 00hReservedandwill be0(Get DisplayStart only)
CX = FirstDisplayedPixelInScanLine(Get DisplayStart only)
DX = FirstDisplayedScanLine(Get DisplayStart only)
______________________________
Input: AX = 4F08h VBESet/Get PaletteFormat
BL = 00h Set DACPalette Format
= 01h Get DACPaletteFormat
BH = Desiredbits ofcolorperprimary
(Set DACPaletteFormat only)
BH = Currentnumberofbits ofcolorperprimary

VBEQuickReference
DOCUMENTREVISION1.1
______________________________

VBEQuickReference
DOCUMENTREVISION1.1
Input: AX = 4F09h VBELoad/UnloadPaletteData
BL = 00h Set PaletteData
= 01h Get PaletteData
= 02h Set SecondaryPalette Data
= 03h Get SecondaryPaletteData
= 80h SetPaletteDataduringVertical Retrace
withBlankBit on
CX = Numberofpaletteregisters toupdate
DX = Firstpaletteregistertoupdate
ES:DI = Tableofpalettevalues (seebelowforformat)
FormatofPaletteValues: Alignment byte, Redbyte, Greenbyte, Bluebyte
______________________________
Input: AX = 4F0Ah VBE2.0 Protected Mode Interface
BL = 00h Returnprotectedmodetable
Output: AX = Status
DI = OffsetofTable
CX = LengthofTableincludingprotectedmodecodeinbytes
______________________________

VBEData Structures
DOCUMENTREVISION1.1
Appendix 2 - VBE Data Structures
VbeInfoBlockstruc
VbeSignature db 'VESA' ;VBESignature
VbeVersion dw 0200h ;VBEVersion
Capabilities db 4 dup (?) ;Capabilitiesofgraphicscontroller
VideoModePtr dd ? ;PointertoVideoModeList
TotalMemory dw ? ; Numberof64kbmemoryblocks
; Added for VBE 2.0
OemSoftwareRev dw ? ;VBEimplementationSoftwarerevision
OemProductNamePtr dd ? ;PointertoProduct NameString
Reserved db 222 dup (?) ;ReservedforVBEimplementationscratch
; area
OemData db 256 dup (?) ; DataAreaforOEMStrings
VbeInfoBlockends

VBEData Structures
DOCUMENTREVISION1.1
ModeInfoBlockstruc
;MandatoryinformationforallVBErevisions
ModeAttributes dw ? ;modeattributes
WinAAttributes db ? ;windowAattributes
WinBAttributes db ? ;windowBattributes
WinGranularity dw ? ;windowgranularity
WinSize dw ? ;windowsize
WinASegment dw ? ;windowAstart segment
WinBSegment dw ? ;windowBstartsegment
WinFuncPtr dd ? ;pointertowindowfunction
BytesPerScanLine dw ? ;bytes perscanline
XResolution dw ? ;horizontalresolutioninpixelsorcharacters
YResolution dw ? ;verticalresolutioninpixelsorcharacters
XCharSize db ? ;charactercellwidthinpixels
YCharSize db ? ;charactercellheightinpixels
NumberOfPlanes db ? ;numberofmemoryplanes
BitsPerPixel db ? ;bitsperpixel
NumberOfBanks db ? ;numberofbanks
MemoryModel db ? ;memorymodeltype
BankSize db ? ;banksizeinKB
NumberOfImagePages db ? ;numberofimages
Reserved db 1 ;reservedforpagefunction
;DirectColorfields(requiredfordirect/6andYUV/7memorymodels)
RedMaskSize db ? ;sizeofdirect colorredmaskinbits
RedFieldPosition db ? ;bitpositionoflsbofredmask
GreenMaskSize db ? ;sizeofdirectcolorgreenmaskinbits
GreenFieldPosition db ? ;bitpositionoflsbofgreenmask
BlueMaskSize db ? ;sizeofdirectcolorbluemaskinbits
BlueFieldPosition db ? ;bitpositionoflsbofbluemask
RsvdMaskSize db ? ;sizeofdirect colorreservedmaskinbits
RsvdFieldPosition db ? ;bitpositionoflsbofreservedmask
DirectColorModeInfo db ? ;directcolormodeattributes
PhysBasePtr dd ? ;physicaladdressforflatmemoryframebuffer
OffScreenMemOffset dd ? ;pointertostart ofoffscreenmemory
OffScreenMemSize dw ? ;amountofoffscreenmemoryin1kunits
Reserved db 206 dup (?) ; remainder of ModeInfoBlock
ModeInfoBlock ends

Vbe20

Recommended

Recommended

More Related Content

What's hot

What's hot (7)

Similar to Vbe20

Similar to Vbe20 (20)

Recently uploaded

Recently uploaded (20)

Vbe20