1GHz X-DSP Chip ALU Unit Design And Implementation

X-DSP chip is designed with45nm CMOS process to achieve1GHz under theworst conditions. The designing and optimization of ALU unit is one of the keytechnologies to improve the working frequency of DSP core, and it is importantlymeaningful to study the circuit design and physical design of ALU unit in the reality.In this paper, based on the background of designing and optimization ALU unit,through the hierarchical circuit design methodology with standard-cells and physicaldesign methodology in hierarchical and manual semi-conduct way, the projectaccomplished the design implementation of high performance ALU unit. The paper hasmainly accomplished these works below:1）Designed and implemented the fixing computation circuits of the ALU unit.based on the function of the computation from the front-end design work, finished thecustom circuit designing working in the right function with the standard-cells; throughthe static timing analysis, iteratively optimizing the circuits, made the critical timingdelay of the fixing computation circuits work in about590ps; during the circuitsoptimization, creatively designed a kind of high performance comparator to decrease thedelay of the circuits of comparing instructions by23%.2）By the manual semi-conduct methodology and hierarchical methodology,accomplished the layout of ALU unit. by the hierarchical methodology, finished thephysical design of the fixing computation units on ALU; using self-development scriptprogram in perl programming language to make the I/O file, accomplished the physicaldesign of the whole ALU unit by the hierarchical methodology; implemented the layoutwith the critical delayed in760ps, powering38.83mW, and in76270um of area;comparing with the automatic physical design methodology, deceased the power ofALU unit layout by5.6%, the area by14%and the delay by4.8%. The result of layoutdesigning had proved the designing progress with manual semi-conduct methodologyand hierarchical methodology is able to improve the quality and parallelism ofdesigning, and to decrease the design circle.3）Accomplished the stimulation and verification of the ALU unit. Studied themethodology of the stimulation and verification on ALU unit; with the planet ofsimulation and verification, verified the function of design on the fixing circuits of ALUunit; mainly verified the validity of the application of the instructions on each fixingunits. The result of the verification proved the ALU unit had satisfied the requirement ofthe system design.