Texas Instruments TVP4020 PERMEDIA 2 User manual

Texas
Instruments
TVP4020 PERMEDIA®2
Programmer’s Reference
Manual
Issue 4

Contents TVP4020 Programmers Reference Manual
iv
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Copyright 1997, Texas Instruments Incorporated

TVP4020 Programmers Reference Manual Contents
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3Dlabs is the worldwide trading name of 3Dlabs Inc. Ltd.
3Dlabs, GLINT and PERMEDIA are registered trademarks of 3Dlabs Inc. Ltd.
Microsoft, Windows and Direct3D are either registered trademarks or trademarks
of Microsoft Corp. in the United States and/or other countries. OpenGL is a
registered trademark of Silicon Graphics, Inc. Macintosh and Power Macintosh
are registered trademarks and QuickDraw is a trademark of Apple Computer Inc.
All other trademarks are acknowledged and recognized.

Contents TVP4020 Programmers Reference Manual
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Contents
1. Introduction........................................................................................................1
1.1 How to use this manual.............................................................................................................. 1
1.2 Further Reading......................................................................................................................... 1
2. Overview ............................................................................................................2
2.1 TVP4020 Key Features.............................................................................................................. 2
2.2 Functional Overview .................................................................................................................. 3
3. Programming Model..........................................................................................6
3.1 PERMEDIA as a Register file ....................................................................................................7
3.2 PERMEDIA I/O Interface ...........................................................................................................9
3.3 Interrupts.................................................................................................................................. 20
3.4 Synchronization ....................................................................................................................... 20
3.5 Host Memory Bypass............................................................................................................... 21
3.6 DMA Controller ........................................................................................................................22
3.7 Register Read back .................................................................................................................22
3.8 Byte Swapping......................................................................................................................... 23
3.9 Red and Blue Swapping ..........................................................................................................23
4. Memory I/O and Organization.........................................................................25
4.1 Patched Data........................................................................................................................... 25
4.2 Localbuffer ............................................................................................................................... 25
4.3 Framebuffer ............................................................................................................................. 27
4.4 Double Buffering......................................................................................................................33
4.5 Texture Buffer.......................................................................................................................... 37
5. Graphics Programming...................................................................................40
5.1 The Graphics HyperPipeline....................................................................................................40
5.2 Delta Unit.................................................................................................................................42
5.3 Rasterizer Unit......................................................................................................................... 48
5.4 Scissor/Stipple Unit.................................................................................................................. 68
5.5 Localbuffer Read and Write Units............................................................................................ 73
5.6 Stencil/Depth Test Unit............................................................................................................77
5.7 Texture Address Unit............................................................................................................... 85
5.8 Texture Read Unit....................................................................................................................88
5.9 YUV Unit..................................................................................................................................95
5.10 Framebuffer Read and Write Units........................................................................................98
5.11 Color DDA Unit ....................................................................................................................105
5.12 Texture/Fog/Blend ............................................................................................................... 109
5.13 Color Format Unit................................................................................................................. 118
5.14 Logical Op Unit ....................................................................................................................121
5.15 Host Out Unit .......................................................................................................................124
6. Initialization....................................................................................................130
6.1 Initializing PERMEDIA............................................................................................................ 130
6.2 System Initialization ............................................................................................................... 130
6.3 Window Initialization............................................................................................................... 134

TVP4020 Programmers Reference Manual Contents
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6.4 Application Initialization ..........................................................................................................137
6.5 Bypass Initialization................................................................................................................138
7. Programming Tips.........................................................................................139
7.1 PCI Bus Issues.......................................................................................................................139
7.2 Graphics Hyperpipeline..........................................................................................................141
7.3 Area Filling Techniques..........................................................................................................142
7.4 Copies and Downloads...........................................................................................................144
7.5 Multi Buffering.........................................................................................................................145
7.6 Overlays .................................................................................................................................146
7.7 Memory Organization.............................................................................................................146
7.8 Chroma Test...........................................................................................................................147
7.9 Configuration for 2D ...............................................................................................................147
8. Delta Programming Examples......................................................................148
Appendix A. Graphics Register Reference......................................................162
Appendix B. Pseudocode Definitions..............................................................272
Appendix C. Screen Widths Table....................................................................274
Appendix D. A Gouraud Shaded Triangle without using the Delta Unit ......276
Appendix E. Register Tables ............................................................................284
Appendix F. TVP4010 and TVP4020 Differences.............................................294
Glossary .............................................................................................................300
Index ...................................................................................................................306

Contents TVP4020 Programmers Reference Manual
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Table of Figures
Figure 2.1 External Interfaces ............................................................................................................. 3
Figure 3.1 DMA Tag Description Format.......................................................................................... 13
Figure 3.2 Indexed Format............................................................................................................... 15
Figure 5.1 Hyperpipeline .................................................................................................................. 41
Figure 5.2 Triangle Mesh................................................................................................................... 43
Figure 5.3 Triangle Fan.....................................................................................................................43
Figure 5.4 Rasterizing a triangle........................................................................................................ 49
Figure 5.5 Polyline............................................................................................................................. 51
Figure 5.6 Relationship between Bitmask and Scanning Directions.................................................55
Figure 5.7 Copy Operation................................................................................................................ 58
Figure 5.8 Real Coordinate Representation...................................................................................... 61
Figure 5.9 Screen Scissor and User Scissor Tests........................................................................... 69
Figure 5.10 Scissor Mode Register................................................................................................... 70
Figure 5.11 AreaStippleMode Register ............................................................................................. 70
Figure 5.12 LBReadMode Register................................................................................................... 75
Figure 5.13 LBWriteMode Register ................................................................................................... 75
Figure 5.14 LBReadFormat / LBWriteFormat Register ..................................................................... 76
Figure 5.15 Depth Interpolation......................................................................................................... 80
Figure 5.16 Depth Derivative Format ................................................................................................ 81
Figure 5.17 StencilMode Register ..................................................................................................... 81
Figure 5.18 StencilData Register....................................................................................................... 81
Figure 5.19 DepthMode Register ......................................................................................................82
Figure 5.20 Window Register............................................................................................................82
Figure 5.21 Texture Address Interpolation........................................................................................ 85
Figure 5.22 Fixed Point S and T Format ...........................................................................................86
Figure 5.23 Fixed Point Q Format..................................................................................................... 86
Figure 5.24 TextureAddressMode..................................................................................................... 87
Figure 5.25 TextureReadMode Register........................................................................................... 90
Figure 5.26 TextureMapFormat Register .......................................................................................... 91
Figure 5.27 TextureDataFormat Register.......................................................................................... 91
Figure 5.28 TexelLUTMode Register ................................................................................................92
Figure 5.29 TexelLUTAddress register .............................................................................................92
Figure 5.30 YUVMode Register......................................................................................................... 97
Figure 5.31 ChromaUpperBound and ChromaLowerBound Registers RGB Format........................ 97
Figure 5.32 ChromaUpperBound and ChromaLowerBound Registers YUV Format ........................ 97
Figure 5.33 FBReadMode Register.................................................................................................103
Figure 5.34 FBWriteMode Register................................................................................................. 103
Figure 5.35 FBReadPixel Register.................................................................................................. 104
Figure 5.36 PackedDataLimits Register.......................................................................................... 104
Figure 5.37Color Representation .................................................................................................... 105
Figure 5.38 Color Interpolation........................................................................................................ 106
Figure 5.39 Fixed Point Color Format ............................................................................................. 106
Figure 5.40 ColorDDAMode Register.............................................................................................. 107
Figure 5.41 Fog Interpolation Over A Triangle................................................................................ 111
Figure 5.42 Fog Interpolant Fixed Point Format.............................................................................. 112
Figure 5.43 Fogging ........................................................................................................................113
Figure 5.44 TextureColorMode Register.........................................................................................115
Figure 5.45 Texel0 Register - RGB and YUV formats..................................................................... 115
Figure 5.46 FogMode Register........................................................................................................116
Figure 5.47 AlphaBlendMode Register............................................................................................ 116

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Figure 5.48 Dither Mode Register....................................................................................................119
Figure 5.49 LogicalOpMode Register ..............................................................................................123
Figure 5.50 FilterMode Register.......................................................................................................127
Figure 5.51 StatisticMode Register..................................................................................................127
Figure 5.52 PickResult Register.......................................................................................................127
Figure 8.1 Geometry of the Mesh and Clip regions. ........................................................................148
List of Tables
Table 2.1 Standard VGA Modes..........................................................................................................4
Table 2.2 VESA SVGA Modes.............................................................................................................5
Table 3.1 Memory Regions..................................................................................................................6
Table 3.2 Region 0 Address Map.........................................................................................................7
Table 4.1 Supported Color Formats..................................................................................................31
Table 5.1 Vertex Parameters.............................................................................................................42
Table 5.2 Draw Command Bit Field Assignments Affecting Delta.....................................................45
Table 5.3 DeltaMode Register Bit Field Assignments........................................................................46
Table 5.4 Rasterizer Command Registers.........................................................................................63
Table 5.5 Rasterizer Control Registers..............................................................................................64
Table 5.6 Render Command Register Fields.....................................................................................65
Table 5.7 Rasterizer Mode Register ..................................................................................................66
Table 5.8 Localbuffer Read/Write Modes...........................................................................................74
Table 5.9 Stencil Comparison Modes................................................................................................78
Table 5.10 Possible Update Operations for Stencil Planes ...............................................................78
Table 5.11 Stencil Operations............................................................................................................78
Table 5.12 Stencil Sources................................................................................................................79
Table 5.13 Depth Comparison Modes ...............................................................................................79
Table 5.14 Depth Sources. ................................................................................................................80
Table 5.15 Depth Interpolation Registers...........................................................................................82
Table 5.16 Texture Interpolation Registers........................................................................................86
Table 5.17 Chroma Test Modes.........................................................................................................96
Table 5.18 Framebuffer Read/Write Modes.....................................................................................100
Table 5.19 Color Interpolation Registers..........................................................................................107
Table 5.20 Logical Operations.........................................................................................................121
Table 5.21 Filter Modes ...................................................................................................................125
Table 7.1 Memory Organization.......................................................................................................147

TVP4020 Programmers Reference Manual Introduction
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1. Introduction
TVP4020 is a high performance PCI/AGP graphics processor that
balances high quality 3D polygon and textured graphics acceleration,
windows acceleration and state-of-the-art MPEG1/MPEG2 playback with
a fast integrated SVGA core, integrated RAMDAC and video ports. This
document provides a high level overview of the architecture of the
TVP4020 graphics processor and is intended as an introduction for
design engineers and project managers planning the implementation of
TVP4020 based systems.
TVP4020 sets the standard for 3D and multimedia acceleration, making
it the ideal solution to meet the increasingly pervasive need for balanced
3D and multimedia acceleration - and all in a single, low cost PCI device.
This document has been written as the primary reference for
programmers and system designers who wish to develop software to
drive TVP4020. Information on programming the I/O registers can be
found in the
TVP4020 Hardware Reference Manual.
TVP4020 is the second generation PERMEDIA device. Compared with
TVP4010, it provides greater flexibility, additional features and enhanced
performance. Throughout this manual the terms TVP4020 and PERMEDIA
are used interchangeably.
An understanding of the principles of 2D and 3D graphics programming
will be useful in reading this document.
1.1 How to use this manual
Chapter 2 gives an overview of PERMEDIA.
Chapter 3 details the programming model for the chip.
Chapter 4 describes the data formats that PERMEDIA supports in the
framebuffer, localbuffer and texture buffer.
Chapter 5 describes how to use PERMEDIA for graphics rendering.
Chapter 6 describes the initialization of PERMEDIA.
Chapter 7 provides tips for programming PERMEDIA.
Chapter 8 provides examples of Delta programming.
Appendix A details the PERMEDIA registers.
Appendix B gives the format used in the pseudocode examples
throughout the document.

Introduction TVP4020 Programmers Reference Manual
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Appendix C gives a table used to set-up common screen widths.

TVP4020 Programmers Reference Manual Introduction
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Appendix D describes how a Gouraud shaded triangle can be rendered
without using the Delta Unit. This is helpful in understanding how the
chip works and
also when dealing with TVP4010 legacy.
Appendix E tabulates the TVP4020 registers.
Appendix F describes the differences between TVP4010 and 2
A Glossary of technical terms follows the Appendices.
An extensive index is included.
1.2 Further Reading
•TVP4020 Data Manual, Texas Instruments
•TVP4020 Architecture Overview, Texas Instruments
•OpenGL Programming Guide, Jackie Neider et al, Reading MA:
Addison-Wesley
•Microsoft WIN32 Software Development Kit 3.1, Microsoft
•Windows NT 3.1 Graphics Programming, Emeryville CA, Ziff-Davis
Press
•Computer Graphics: Principles and Practice, James D. Foley et al,
Reading MA: Addison-Wesley
•Programmer’s Guide to the EGA, VGA and Super VGA Cards,
Richard F. Ferraro, Reading MA: Addison-Wesley, ISBN 0-201-
62490-7