An ASIP Instruction Set Optimization Algorithm with Functional Module Sharing Constraint

Alauddin Y. ALOMARY  Masaharu IMAI  Nobuyuki HIKICHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E76-A   No.10   pp.1713-1720
Publication Date: 1993/10/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
ASIP,  instruction set optimization,  branch-and-bound method,  functional module sharing,  PEAS system,  

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One of the most interesting and most analyzed aspects of the CPU design is the instruction set design. How many and which operations to be provided by hardware is one of the most fundamental issues relaing to the instruction set design. This paper describes a novel method that formulates the instruction set design of ASIP (an Application Specific Integrated Processor) using a combinatorial appoach. Starting with the whole set of all possible candidata instructions that represesnt a given application domain, this approach selects a subset that maximizes the performance under the constraints of chip area, power consumption, and functional module sharing relation among operations. This leads to the efficient implementation of the selected instructions. A branch-and-bound algorithm is used to solve this combinatorial optimization problem. This approach selects the most important instructions for a given application as well as optimizing the hardware resources that implement the selected instructions. This approach also enables designers to predict the perfomance of their design before implementing them, which is a quite important feature for producing a quality design in reasonable time.