Master the fundamental concepts of real-time embedded system programming and jumpstart your embedded projects with effective design and implementation practices. This book bridges the gap between higher abstract modeling concepts and the lower-level programming aspects of embedded systems development. You gain a solid understanding of real-time embedded systems with detailed practical examples and industry wisdom on key concepts, design processes, and the available tools and methods.
Delve into the details of real-time programming so you can develop a working knowledge of the common design patterns and program structures of real-time operating systems (RTOS). The objects and services that are a part of most RTOS kernels are described and real-time system design is explored in detail. You learn how to decompose an application into units and how to combine these units with other objects and services to create standard building blocks. A rich set of ready-to-use, embedded design “building blocks” is also supplied to accelerate your development efforts and increase your productivity.
Experienced developers new to embedded systems and engineering or computer science students will both appreciate the careful balance between theory, illustrations, and practical discussions. Hard-won insights and experiences shed new light on application development, common design problems, and solutions in the embedded space. Technical managers active in software design reviews of real-time embedded systems will find this a valuable reference to the design and implementation phases.
Qing Li is a senior architect at Wind River Systems, Inc., and the lead architect of the company’s embedded IPv6 products. Qing holds four patents pending in the embedded kernel and networking protocol design areas. His 12+ years in engineering include expertise as a principal engineer designing and developing protocol stacks and embedded applications for the telecommunications and networks arena. Qing was one of a four-member Silicon Valley startup that designed and developed proprietary algorithms and applications for embedded biometric devices in the security industry.
Caroline Yao has more than 15 years of high tech experience ranging from development, project and product management, product marketing, business development, and strategic alliances. She is co-inventor of a pending patent and recently served as the director of partner solutions for Wind River Systems, Inc.
About the Authors
13.2 Dynamic Memory Allocation in Embedded Systems
Chapter 3 shows that the program code, program data, and system stack occupy the physical memory after program initialization completes. Either the RTOS or the kernel typically uses the remaining physical memory for dynamic memory allocation. This memory area is called the heap. Memory management in the context of this chapter refers to the management of a contiguous block of physical memory, although the concepts introduced in this chapter apply to the management of non-contiguous memory blocks as well. These concepts also apply to the management of various types of physical memory. In general, a memory management facility maintains internal information for a heap in a reserved memory area called the control block. Typical internal information includes:
· the starting address of the physical memory block used for dynamic memory allocation,
· the overall size of this physical memory block, and
· the allocation table that indicates which memory areas are in use, which memory areas are free, and the size of each free region.
This chapter examines aspects of memory management through an example implementation of the malloc and free functions for an embedded system.
