We address the problem of instruction selection in code generation for embedded digital signal processors. Recent work has shown that this task can be efficiently solved by tree covering with dynamic programming, even in combination with the task of register allocation. However, performing instruction selection by tree-covering only does not exploit available instruction-level parallelism, for instance in form of multiply-accumulate instructions or parallel data moves. In this paper we investigate how such complex instructions may affect detection of optimal treecovers, and we present a two-phase scheme for instruction selection which exploits available instruction-level parallelism. At the expense of higher compilation time, this technique may significantly increase the code quality compared to previous work, which is demonstrated for a widespread DSP.

Embedded systems are broadly defined as systems designed for a particular application. The functionality of an embedded system is divided into hardware and software components. Synthesis of the hardware component involves designing a custom circuit for the hardware portion of the input application. Synthesis of the software component consists of designing a processor that is suited for the software portion of the input application and generating code that implements the functionality of the software component on the designed processor. Short design cycles and increasing embedded system complexity make it impractical to perform manual processor architecture exploration and code generation. In order to effectively explore the design space for the software component of embedded systems, a retargetable code generator is required. This thesis presents the Aviv retargetable code generator that generates optimized machine code for a specified target processor. Aviv is capable of compiling ap...

This tutorial responds to the rapidly increasing use of cores in general and of processor cores in particular for implementing systems-on-a-chip. In the first part of this text, we will provide a brief introduction to various cores. Applications can be found in most segments of the embedded systems market. These applications demand for extreme efficiency, and in particular for efficient processorarchitecturesand for efficient embedded software. In the second part of this text, we will show that current compilers do not provide the required efficiency and we will give an overview over new compiler optimization techniques,which aim at making assembly language programming for embedded software obsolete. Thesenew techniquestake advantageof the special characteristics of embedded software and embedded architectures. Due to efficiency considerations, processorarchitecturesoptimized for application domains or even for particular applications are of interest. This results in a large number of ...

In this paper, we present the application of dynamic trellis diagrams (DTDs) to automatic translation of data flow graphs (DFGs) into highly optimized programs for digital signal processors (DSPs). In contrast to static trellis diagrams (STDs), which may be precalculated, DTDs are built at runtime and adapted exactly to the local requirements. Therefore, DTDs are more flexible and need less program memory. Due to the significant reduction in memory size, the increase of compilation time is only moderate. At present, the concept of DTDs has been successfully applied to DFG compiler implementations for a variety of general purpose DSP families, including Motorola’s DSP56000 and Analog Devices ’ ADSP2100.

This tutorial responds to the increasing use of embedded processors for implementing systemson -a-chip. We will provide an introduction to embedded processors and we will show that current compilers do not provide the required efficiency. We will give an overview over new compiler optimization techniques, which aim at making assembly language programming for embedded software obsolete. Finally, we will present techniques for retargeting compilers to new architectures. One of the approaches closes the gap between electronic CAD and compiler generation. I. Embedded Processors, Core Processors and Embedded Systems There has recently been a huge amount of interest in embedded processors in general and in embedded core processors in particular. What is the main reason behaind this huge interest? The main reason is flexibility. It is possible to change the overall behavior of a processor-based design by changing the program that is executed on the processor. This way, it is possible to acc...