DesiJ: A Tool for Decomposing STGs

Work Group – Basics of Systems Engineering

Mark Schaefer, Walter Vogler, Dominic Wist and Ralf Wollowski

DesiJ: A Tool for Decomposing STGs


2

Outline

■ Motivation

□ Decomposition-based SI Logic Synthesis

□ Idea of Decomposition

■ DesiJ

□ Functionality

□ User Interface

□ Installation requirements

■ Live Demo

■ Integration into the Balsa Design Flow


3

Outline

■ Motivation



■ DesiJ

□ Functionality

□ User Interface


■ Live Demo



4

From SI Logic Synthesis to …

dtack-

ldtack-

dsr+ lds+

ldtack+lds-d-

dsr- dtack+ d+

Specification:Signal Transition Graph (STG)

State Graph

State Graph with CSC (Complete State Coding)

Next-State Functions

Gate netlist

Reachabilityanalysis

Decomposed Functions

State encoding

Boolean minimization

Logic decomposition

Technologymapping

00/000 10/00000/010

01/010 01/000 11/000

11/10001/10001/110

01/111 11/111 11/101

11/100

10/100

(dsr ldtack / lds dtack d)

dtack- dsr+

dtack- dsr+

dtack- dsr+

lds-

ldtack-

lds-

ldtack-

lds-

ldtack-

lds+

ldtack+

d+

dtack+dsr-

d-

00/0000 10/000000/0100

01/0100 01/0000 11/0000

11/100001/100001/1100

01/1111 11/1111 11/1011

11/1001

10/1001

(dsr ldtack / lds dtack d csc)

dtack- dsr+

dtack- dsr+

dtack- dsr+

lds-

ldtack-

lds-

ldtack-

lds-

ldtack- lds+

ldtack+

d+

dtack+dsr-

d-

10/0001

01/1110

csc+

csc-

lds = d + cscdtack = d

d = ldtack · csccsc = dsr · (csc + ldtack)


5

Decomposition-based Logic Synthesis

Specification:STG

State Graph

State Graph with CSC (Complete State Coding)


Gate netlist



State encoding


Logic decomposition

Technologymapping

Specification:STG

State Graphs

State Graphs with CSC (Complete State Coding)


Gate netlist

STG decomposition


State encoding


Logic decomposition

Technologymapping

Component STGs


Petrify

DesiJ

“State Space Explosion“


6

Idea of STG-Decomposition

VME Bus Controller

DataTransceiver

Dev

ice

BU

S

dsr

dtack

lds

ldtack

dVME BusController

DataTransceiver

Dev

ice

BU

S

dsr

dtack

lds

ldtack

d

comp 2

comp1


7

STG-Decomposition Technique

dtack-

ldtack-

dsr+ lds+

ldtack+lds-d-

dsr- dtack+ d+

(out) = { {lds, d} , {dtack} }

ldtack-

dsr+ lds+

ldtack+lds-d-

dsr- d+

dtack-

d- dtack+

d+

VME Bus Controller

DataTransceiver

Dev

ice

BU

S

dsr

dtack

lds

ldtack

d

VME BusController

DataTransceiver

Dev

ice

BU

S

dsr

dtack

lds

ldtack

d

comp 2

comp1

Elimination of irrelevant signals

(transition contraction)


8

Results – Success Stories

Avoidance of state explosion

Effectivity and efficiency in logic synthesis

Benchmark Specification Components

FIFO 832 26 + 12 + 12 + 8 + 4 + 4 = 66

locked2 166 34+20+20 = 74

mread-8932 8932 36 + 36 + 18 + 18 + 12 + 10 = 130

Benchmark Petrify DesiJ + Petrify

2pp.arb.nch.09.csc.g 116 s 4 s

2pp-wk.12.csc.g impossible 18 s

SeqParTree-3.g 59 s 1 s

SeqParTree-5.g impossible 10 s


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Outline

■ Motivation



■ DesiJ

□ Functionality

□ User Interface


■ Live Demo



10

Primary Function: Decomposition

Complex Specification

STG

Synthesizer

Asynchronous System Netlist

instead

Complex Specification

STG

Decomposer

(smaller)STG

Components

Synthesizer

Asynchronous Circuit Netlist

Decomposition

SI Logic

SynthesisPetrify Petrify

DesiJ

Punf & Mpsat

R

Configuration of the Decomposition

■ Decomposition strategy (basic, lazyBack, tree etc.)

■ Specification of the output partition

■ Insertion of internal communication signals to enable SI logic synthesis

■ Deletion of redundant places

□ simple versions (loop-only, duplicate …)

□ shortcut places

□ implicit places (with unfoldings)


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Secondary Functions

■ Functions for STG manipulation

□ deletion of redundant places

□ contraction of dummy transitions

□ creation of particular benchmark STGs (e.g. SeqParTree)

■ STG conversion to a postscript document (requires graphviz package and a working postscript installation to display the result)

■ Reachability graph generation (simple version)

■ Verification of the decomposition implementation (test for STG-bisimulation)


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User Interface

■ Primary UI: Command Line Interface

□ most powerful UI (all functions and options are accessible)

□ easy accessible by other tools (see later)

■ Secondary UI: a rudimentary GUI

□ for research purposes

□ works in an old DesiJ version only


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Installation requirements

■ DesiJ comes as a Jar-Archive (JRE 1.6 or higher is required)

■ Third party tools are required

□ For synthesis: Petrify, Punf, Mpsat

□ For visualization: Graphviz, Ghostview

■ Full functionality is only provided for Linux so far

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15

Outline

■ Motivation



■ DesiJ

□ Functionality

□ User Interface


■ Live Demo


SeqParTree-3


16

Outline

■ Motivation



■ DesiJ

□ Functionality

□ User Interface


■ Live Demo


Control Circuit

Cluster 1

Decomposition-Based Logic Synthesis

Balsa Specification

Balsa Compiler(balsa-c)

Handshake Circuit

Data Path HCs

STG composer

STG 1 STG n

Decomposer(improved DesiJ)

Decomposer(improved DesiJ)

C-STG 1.1 C-STG 1.i C-STG n.1 C-STG n.j

PetrifyPunf &Mpsat

PetrifyPunf &Mpsat

SI Circuit SI Circuit SI Circuit SI Circuit

Merging Agent

Technolgy-Mapper(balsa-netlist)

Verilog Netlist

ControlHC

ControlHC

STG Extractor

HC-STG

STG composer

STG Extractor

HC-STG

Control HC Mixed HC Data HC

Clustering Agent

Cluster n

ControlHC

Data PathExtractor

MixedHC

Verilognetlist

Failure

17

already available

partially available

not available (have to be developed)

Proposed CAD Framework for

Decomposition-based HDL Synthesis

of Asynchronous Circuits

Cluster-STG 1 Cluster-STG n

More Information

■ Website (with download version): http://www.informatik.uni-augsburg.de/en/chairs/swt/ti/research/tools/desij/

■ Mark Schaefer. DesiJ - a tool for STG decomposition. Technical Report 2007-11, Institute of Computer Science, University of Augsburg, 2007, (available at http://www.informatik.uni-augsburg.de/en/chairs/swt/ti/research/tr/2007_desij/)

■ Mark Schaefer, Dominic Wist and Ralf Wollowski. DesiJ – Enabling Decomposition-Based Synthesis of Complex Asynchronous Controllers. To appear in the Proceedings of ACSD’09.

■ DesiJ help: via the command line call desij --help

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Documents

DesiJ: A Tool for Decomposing STGs