Architecture Description Languages for Programmable Embedded Systems P. Mishra and N. Dutt IEE...

Architecture Description Languages for Programmable Embedded Systems

P. Mishra and N. Dutt

IEE Proc.-Comput. Digit. Tech., Vol. 152, No. 3, May 2005

Speaker: Wen-Kai Huang

2005/11/18 Architecture Description Languages for Programmable embedded Systems 2/24

Abstract Embedded systems present a tremendous opportunity

to customize designs by exploiting the application behavior. Shrinking time-to-market, coupled with short product lifetimes, create a critical need for rapid exploration and evaluation of candidate architectures. Architecture description languages (ADL) enable exploration of programmable architectures for a given set of application programs under various design constraints such as area, power and performance. The ADL is used to specify programmable embedded systems, include processor, coprocessor and memory architectures. The ADL specification is used to generate a variety of software tools.


Abstract (Cont.) The paper surveys the existing ADLs in terms of (a) the

inherent features of the languages and (b) the methodologies they support to enable simulation, compilation, synthesis, test generation and validation of programmable embedded systems. It concludes with a discussion of the relative merits and demerits of the existing ADLs and expected features of future ADLs.


What’s the Problem Embedded systems are everywhere

Architecture Description Languages (ADL) are traditionally used to enable rapid design space exploration

Example system:

Key Features:

• Shrinking time-to-market

• Shorten product lifetime

So we need:

Rapid design space exploration


ADL-Driven Framework


Related Works Qin and Malik [1]

Surveyed and compared the ADLs to highlight their strengths and weaknesses for retargetable compilation

Tomiyama et al. [2] Classified existing ADLs into four categories

Synthesis Compiler generation Simulator generation Validation

This paper presents a comprehensive survey and accompanying methodologies for programmable embedded systems

Introduction to ADLs and Some Examples


Language Comparison

How do ADLs differ from conventional non-ADLs?? Programming languages

EX: C, C++ Hardware description languages (HDL)

VHDL, Verilog Modeling languages

EX: UML, SystemC


Classification of ADLs

Content

Objective


MIMOLA

Structural ADLSpecification of program counter

Specification of ALU

Specification of connections

•Purpose

•Hardware synthesis

•Program generation

•Weakness

•Lack of pipeline information


nML Behavioral ADL

Example of instruction specification•Purpose

•Software compilation

•Instruction-set simulation

•Weakness

•Hard to model the complicated processors


EXPRESSION

Mixed ADL

Data-path specification


EXPRESSION (Cont.)

•Purpose

•Software compilation



•Weakness

•Control path is not modeled

Instruction specification


LISA

Mixed ADLPipeline specification

Operation specification

•Purpose




AIDL

Partial ADL Aims at validation of the pipeline behavior

Data forwarding Out-of-order completion

ADL Applications


Software Toolkit Generation


Compiler Generation

Retargetable compiler Architecture template based (non-ADL based)

EX: Valen C, GNU-based C/C++ Explicit behavioral information based

EX: AVIV using ISDL, CHESS using nML, Elcor using MDes

Behavioral information generation based EX: MSSQ using MIMOLA, LISA-based, EXPRESS usi

ng EXPRESSION


Simulator Generation

Interpretation-Based Simulator Compilation-Based Simulator Interpretive + Compiled Simulator


Hardware Generation Parameterized processor core based

EX: Xtensa, Jazz, PEAS ADL-based

EX: HGEN using ISDL, GO using nML, LISA-based


Hardware Validation


Validation of ADL

Static verify Connectedness False pipeline Data-transfer paths

Dynamic verify Instruction flow in the pipeline

(More detail discussion can be found in [ 58 – 63 ] )


Comparative Study

Noted by speaker:

It seems that the EXPRESSION would be the best choice for microprocessor validation


Conclusions

The architecture description language (ADL) is an important modeling tool for future SOC design Hardware synthesis Software toolkit generations Test generations

This paper gives a comprehensive survey for several popular ADLs

Architecture Description Languages for Programmable Embedded Systems P. Mishra and N. Dutt IEE...

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