嵌入式系統由於先天硬體資源的限制，以及價格性能比的考量，常使用模擬的方式來處理浮點數運算。本論文第一部份將探討不使用浮點數硬體加速之系統如何處理浮點數運算，以及浮點數硬體存在與否對整體效能上的影響，和使用浮點數與定點數之效能評估；同時將探討如何移植定點數版的Nano-X視窗系統到Versitle PB/926EJ-S發展版上。

　　由於市場需求及硬體的快速發展，嵌入式系統也逐漸有三維顯示的產品問世。而如欲發展3D繪圖，則需要3D繪圖介面的標準(API)，來簡化程式開發。OpenGL~ES (OpenGL for Embedded System)是由Khronos組織所主導，目標是發展出適合於嵌入式系統的3D繪圖精簡API。本論文第二部分將探討EGL之實做，即OpenGL~ES與Nano-X間的介面，以及類似GLUT (OpenGL Utility Toolkits)之函式庫之實做，旨在讓OpenGL程式設計師不需要了解如何處理視窗介面，即可發展在嵌入式系統上視窗介面之OpenGL應用程式，並可達到跨平台的效果。

　　Embedded systems often use several ways to emulate floating-point computation, due to the limitation of hardware resources and the performance/cost consideration. The first part of this thesis will discuss how systems without hardware support emulate floating point operation, and the performance difference between whether hardware floating-point units exists or not, and finally the performance evaluation between the usage of floating-point and fixed-point. In the mean time, we will also discuss the porting process of Nano-X fixed-point version to the Versatile PB/926EJ-S development board.

　　Due to the growing market demand and the big improvement of hardware, there are several 3D-display applications beginning to be presented to the public. In order to develop 3D programs, we need a standard API to reduce our development time. OpenGL~ES is a royalty-free, cross-platform API for full-function 2D and 3D graphics on embedded systems developed by The Khronos Group. The second part of this thesis will discuss the implementation of EGL---the interface between windowing system and the OpenGL~ES rendering API---and the GLUT (OpenGL Utility Toolkits)-like library, in order to make OpenGL programmers' life easier.

List of Tables . . . . . . . . . . . . . . . . . .. iv
List of Figures . . . . . . . . . . . . . . . . . .. v
List of Listings . . . . . . . . . . . . . . . . .. vi
Acknowledgments . . . . . . . . . . . . . . . . . .viii
Chapter 1 Introduction . . . . . . . . . . . . . . . 1
1.1 Background and Motivation . . . . . . . . . . . . 1
1.2 Organization of the Thesis. . . . . . . . . . . . 2
Chapter 2 RelatedWork . . . . . . . . . . . . . . . 3
2.1 Why Linux? . . . . . . . . . . . . . . . . . . . 3
2.1.1 The Market . . . . . . . . . . . . . . . . . . 3
2.1.2 Advanced Technology . . . . . . . . . . . . . . 3
2.1.3 GPL and Open Source . . . . . . . . . . . . . . 4
2.2 Introduction to Embedded System . . . . . . . . . 4
2.2.1 Characteristics . . . . . . . . . . . . . . . . 4
2.2.2 Applications . . . . . . . . . . . . . . . . . 4
2.2.3 The Design of Embedded Systems . . . . . . . . 5
2.3 Graphics User Interface on Embedded Linux . . . . 6
2.3.1 Qt/Embedded . . . . . . . . . . . . . . . . . . 6
2.3.2 GTK+ . . . . . . . . . . . . . . . . . . . . . 6
2.3.3 MiniGUI . . . . . . . . . . . . . . . . . . . . 6
2.3.4 Nano-X . . . . . . . . . . . . . . . . . . . . 7
2.4 OpenGL ES . . . . . . . . . . . . . . . . . . . . 8
2.4.1 Introduction . . . . . . . . . . . . . . . . . 8
2.4.2 EGL . . . . . . . . . . . . . . . . . . . . . . 8
2.4.3 GLUT . . . . . . . . . . . . . . . . . . . . . 9
Chapter 3 Floating-Point versus Fixed-Point . . . .. 10
3.1 Introduction . . . . . . . . . . . . . . . . . .10
3.1.1 Floating-Point . . . . . . . . . . . . . . . . 10
3.1.2 Fixed-Point . . . . . . . . . . . . . . . . .. 10
3.2 How OS Handling Floating-Point . . . . . . . . . 11
3.2.1 Hardware Support . . . . . . . . . . . . . . . 11
3.2.2 Software Support . . . . . . . . . . . . . . . 12
Chapter 4 Porting Nano-X . . . . . . . . . . . . .. 14
4.1 Layered Design . . . . . . . . . . . . . . . . . 14
4.1.1 Device Drivers . . . . . . . . . . . . . . . . 14
4.1.2 MicroGUI - Device Independent Graphics Engine. 15
4.1.3 Applications Programmer Interfaces . . . . . . 15
4.2 Compiling Nano-X . . . . . . . . . . . . . . . . 16
4.3 Changing Floating-Point to Fixed-Point Version . 17
Chapter 5 Integrating Nano-X and OpenGL ES . . . . .21
5.1 Overview . . . . . . . . . . . . . . . . . . . . 21
5.2 Implementing EGL . . . . . . . . . . . . . . . . 24
5.2.1 Introduction . . . . . . . . . . . . . . . . . 24
5.2.2 Initialization . . . . . . . . . . . . . . . . 24
5.2.3 Configuration Management . . . . . . . . . . . 24
5.2.4 Rendering Surfaces . . . . . . . . . . . . . . 25
5.2.5 Rendering Contexts . . . . . . . . . . . . . . 25
5.2.6 Posting the Color Buffer . . . . . . . . . . . 26
5.3 Implementing GLUT-Like APIs . . . . . . . . . . .27
5.3.1 Introduction . . . . . . . . . . . . . . . . . 27
5.3.2 Initialization . . . . . . . . . . . . . . . . 28
5.3.3 Window Management . . . . . . . . . . . . . . .30
5.3.4 Overlay Management . . . . . . . . . . . . . . 33
5.3.5 Menu Management . . . . . . . . . . . . . . . .33
5.3.6 Callback Registration . . . . . . . . . . . . .33
5.3.7 Color Index Colormap Management . . . . . . . .35
5.3.8 State Retrieval . . . . . . . . . . . . . . . .35
5.3.9 Beginning Event Processing . . . . . . . . . . 35
5.3.10 Font Rendering . . . . . . . . . . . . . . . .39
5.3.11 Geometric Object Rendering . . . . . . . . . .40
Chapter 6 Experimental Results and Performance Evaluation . . .41
6.1 Development Enviroment. . . . . . . . . . . . . .41
6.1.1 Target Platform . . . . . . . . . . . . . . . .41
6.1.2 Host platform . . . . . . . . . . . . . . . . .44
6.2 Building Toolchains and Preparing the System. . .44
6.2.1 Host Side . . . . . . . . . . . . . . . . . . .44
6.2.2 Target Side . . . . . . . . . . . . . . . . . .46
6.3 Floating-Point Performance Evaluation . . . . . .46
6.3.1 Evaluation Details . . . . . . . . . . . . . . 47
6.3.2 Evaluation Result . . . . . . . . . . . . . . .53
6.4 Integrating Nano-X and OpenGL ES . . . . . . . . 54
6.4.1 Building the system . . . . . . . . . . . . . .54
6.4.2 Experimental Results. . . . . . . . . . . . . .56
Chapter 7 Conclusion and FutureWorks. . . . . . . . .58
7.1 Conclusion. . . . . . . . . . . . . . . . . . . .58
7.2 Future Works. . . . . . . . . . . . . . . . . . .59

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