/**CFile**************************************************************** FileName [abcRefactor.c] SystemName [ABC: Logic synthesis and verification system.] PackageName [Network and node package.] Synopsis [Resynthesis based on collapsing and refactoring.] Author [Alan Mishchenko] Affiliation [UC Berkeley] Date [Ver. 1.0. Started - June 20, 2005.] Revision [$Id: abcRefactor.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $] ***********************************************************************/ #include "abc.h" #include "dec.h" //////////////////////////////////////////////////////////////////////// /// DECLARATIONS /// //////////////////////////////////////////////////////////////////////// typedef struct Abc_ManRef_t_ Abc_ManRef_t; struct Abc_ManRef_t_ { // user specified parameters int nNodeSizeMax; // the limit on the size of the supernode int nConeSizeMax; // the limit on the size of the containing cone int fVerbose; // the verbosity flag // internal data structures DdManager * dd; // the BDD manager Vec_Str_t * vCube; // temporary Vec_Int_t * vForm; // temporary Vec_Ptr_t * vVisited; // temporary Vec_Ptr_t * vLeaves; // temporary // node statistics int nLastGain; int nNodesConsidered; int nNodesRefactored; int nNodesGained; // runtime statistics int timeCut; int timeBdd; int timeDcs; int timeSop; int timeFact; int timeEval; int timeRes; int timeNtk; int timeTotal; }; static void Abc_NtkManRefPrintStats( Abc_ManRef_t * p ); static Abc_ManRef_t * Abc_NtkManRefStart( int nNodeSizeMax, int nConeSizeMax, bool fUseDcs, bool fVerbose ); static void Abc_NtkManRefStop( Abc_ManRef_t * p ); static Dec_Graph_t * Abc_NodeRefactor( Abc_ManRef_t * p, Abc_Obj_t * pNode, Vec_Ptr_t * vFanins, bool fUpdateLevel, bool fUseZeros, bool fUseDcs, bool fVerbose ); //////////////////////////////////////////////////////////////////////// /// FUNCTION DEFITIONS /// //////////////////////////////////////////////////////////////////////// /**Function************************************************************* Synopsis [Performs incremental resynthesis of the AIG.] Description [Starting from each node, computes a reconvergence-driven cut, derives BDD of the cut function, constructs ISOP, factors the ISOP, and replaces the current implementation of the MFFC of the node by the new factored form, if the number of AIG nodes is reduced and the total number of levels of the AIG network is not increated. Returns the number of AIG nodes saved.] SideEffects [] SeeAlso [] ***********************************************************************/ int Abc_NtkRefactor( Abc_Ntk_t * pNtk, int nNodeSizeMax, int nConeSizeMax, bool fUpdateLevel, bool fUseZeros, bool fUseDcs, bool fVerbose ) { ProgressBar * pProgress; Abc_ManRef_t * pManRef; Abc_ManCut_t * pManCut; Dec_Graph_t * pFForm; Vec_Ptr_t * vFanins; Abc_Obj_t * pNode; int clk, clkStart = clock(); int i, nNodes; assert( Abc_NtkIsStrash(pNtk) ); // cleanup the AIG Abc_AigCleanup(pNtk->pManFunc); // start the managers pManCut = Abc_NtkManCutStart( nNodeSizeMax, nConeSizeMax, 2, 1000 ); pManRef = Abc_NtkManRefStart( nNodeSizeMax, nConeSizeMax, fUseDcs, fVerbose ); pManRef->vLeaves = Abc_NtkManCutReadCutLarge( pManCut ); // compute the reverse levels if level update is requested if ( fUpdateLevel ) Abc_NtkStartReverseLevels( pNtk ); // resynthesize each node once nNodes = Abc_NtkObjNumMax(pNtk); pProgress = Extra_ProgressBarStart( stdout, nNodes ); Abc_NtkForEachNode( pNtk, pNode, i ) { Extra_ProgressBarUpdate( pProgress, i, NULL ); // skip the constant node if ( Abc_NodeIsConst(pNode) ) continue; // skip the nodes with many fanouts if ( Abc_ObjFanoutNum(pNode) > 1000 ) continue; // stop if all nodes have been tried once if ( i >= nNodes ) break; // compute a reconvergence-driven cut clk = clock(); vFanins = Abc_NodeFindCut( pManCut, pNode, fUseDcs ); pManRef->timeCut += clock() - clk; // evaluate this cut clk = clock(); pFForm = Abc_NodeRefactor( pManRef, pNode, vFanins, fUpdateLevel, fUseZeros, fUseDcs, fVerbose ); pManRef->timeRes += clock() - clk; if ( pFForm == NULL ) continue; // acceptable replacement found, update the graph clk = clock(); Dec_GraphUpdateNetwork( pNode, pFForm, fUpdateLevel, pManRef->nLastGain ); pManRef->timeNtk += clock() - clk; Dec_GraphFree( pFForm ); } Extra_ProgressBarStop( pProgress ); pManRef->timeTotal = clock() - clkStart; // print statistics of the manager if ( fVerbose ) Abc_NtkManRefPrintStats( pManRef ); // delete the managers Abc_NtkManCutStop( pManCut ); Abc_NtkManRefStop( pManRef ); // put the nodes into the DFS order and reassign their IDs Abc_NtkReassignIds( pNtk ); // fix the levels if ( fUpdateLevel ) Abc_NtkStopReverseLevels( pNtk ); else Abc_NtkGetLevelNum( pNtk ); // check if ( !Abc_NtkCheck( pNtk ) ) { printf( "Abc_NtkRefactor: The network check has failed.\n" ); return 0; } return 1; } /**Function************************************************************* Synopsis [Resynthesizes the node using refactoring.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ Dec_Graph_t * Abc_NodeRefactor( Abc_ManRef_t * p, Abc_Obj_t * pNode, Vec_Ptr_t * vFanins, bool fUpdateLevel, bool fUseZeros, bool fUseDcs, bool fVerbose ) { int fVeryVerbose = 0; Abc_Obj_t * pFanin; Dec_Graph_t * pFForm; DdNode * bNodeFunc; int nNodesSaved, nNodesAdded, i, clk; char * pSop; int Required; Required = fUpdateLevel? Abc_NodeReadRequiredLevel(pNode) : ABC_INFINITY; p->nNodesConsidered++; // get the function of the cut clk = clock(); bNodeFunc = Abc_NodeConeBdd( p->dd, p->dd->vars, pNode, vFanins, p->vVisited ); Cudd_Ref( bNodeFunc ); p->timeBdd += clock() - clk; // if don't-care are used, transform the function into ISOP if ( fUseDcs ) { DdNode * bNodeDc, * bNodeOn, * bNodeOnDc; int nMints, nMintsDc; clk = clock(); // get the don't-cares bNodeDc = Abc_NodeConeDcs( p->dd, p->dd->vars + vFanins->nSize, p->dd->vars, p->vLeaves, vFanins, p->vVisited ); Cudd_Ref( bNodeDc ); nMints = (1 << vFanins->nSize); nMintsDc = (int)Cudd_CountMinterm( p->dd, bNodeDc, vFanins->nSize ); // printf( "Percentage of minterms = %5.2f.\n", 100.0 * nMintsDc / nMints ); // get the ISF bNodeOn = Cudd_bddAnd( p->dd, bNodeFunc, Cudd_Not(bNodeDc) ); Cudd_Ref( bNodeOn ); bNodeOnDc = Cudd_bddOr ( p->dd, bNodeFunc, bNodeDc ); Cudd_Ref( bNodeOnDc ); Cudd_RecursiveDeref( p->dd, bNodeFunc ); Cudd_RecursiveDeref( p->dd, bNodeDc ); // get the ISOP bNodeFunc = Cudd_bddIsop( p->dd, bNodeOn, bNodeOnDc ); Cudd_Ref( bNodeFunc ); Cudd_RecursiveDeref( p->dd, bNodeOn ); Cudd_RecursiveDeref( p->dd, bNodeOnDc ); p->timeDcs += clock() - clk; } // always accept the case of constant node if ( Cudd_IsConstant(bNodeFunc) ) { p->nLastGain = Abc_NodeMffcSize( pNode ); p->nNodesGained += p->nLastGain; p->nNodesRefactored++; Cudd_RecursiveDeref( p->dd, bNodeFunc ); if ( Cudd_IsComplement(bNodeFunc) ) return Dec_GraphCreateConst0(); return Dec_GraphCreateConst1(); } // get the SOP of the cut clk = clock(); pSop = Abc_ConvertBddToSop( NULL, p->dd, bNodeFunc, bNodeFunc, vFanins->nSize, p->vCube, -1 ); p->timeSop += clock() - clk; // get the factored form clk = clock(); pFForm = Dec_Factor( pSop ); free( pSop ); p->timeFact += clock() - clk; // mark the fanin boundary // (can mark only essential fanins, belonging to bNodeFunc!) Vec_PtrForEachEntry( vFanins, pFanin, i ) pFanin->vFanouts.nSize++; // label MFFC with current traversal ID Abc_NtkIncrementTravId( pNode->pNtk ); nNodesSaved = Abc_NodeMffcLabel( pNode ); // unmark the fanin boundary and set the fanins as leaves in the form Vec_PtrForEachEntry( vFanins, pFanin, i ) { pFanin->vFanouts.nSize--; Dec_GraphNode(pFForm, i)->pFunc = pFanin; } // detect how many new nodes will be added (while taking into account reused nodes) clk = clock(); nNodesAdded = Dec_GraphToNetworkCount( pNode, pFForm, nNodesSaved, Required ); p->timeEval += clock() - clk; // quit if there is no improvement if ( nNodesAdded == -1 || nNodesAdded == nNodesSaved && !fUseZeros ) { Cudd_RecursiveDeref( p->dd, bNodeFunc ); Dec_GraphFree( pFForm ); return NULL; } // compute the total gain in the number of nodes p->nLastGain = nNodesSaved - nNodesAdded; p->nNodesGained += p->nLastGain; p->nNodesRefactored++; // report the progress if ( fVeryVerbose ) { printf( "Node %6s : ", Abc_ObjName(pNode) ); printf( "Cone = %2d. ", vFanins->nSize ); printf( "BDD = %2d. ", Cudd_DagSize(bNodeFunc) ); printf( "FF = %2d. ", 1 + Dec_GraphNodeNum(pFForm) ); printf( "MFFC = %2d. ", nNodesSaved ); printf( "Add = %2d. ", nNodesAdded ); printf( "GAIN = %2d. ", p->nLastGain ); printf( "\n" ); } Cudd_RecursiveDeref( p->dd, bNodeFunc ); return pFForm; } /**Function************************************************************* Synopsis [Starts the resynthesis manager.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ Abc_ManRef_t * Abc_NtkManRefStart( int nNodeSizeMax, int nConeSizeMax, bool fUseDcs, bool fVerbose ) { Abc_ManRef_t * p; p = ALLOC( Abc_ManRef_t, 1 ); memset( p, 0, sizeof(Abc_ManRef_t) ); p->vCube = Vec_StrAlloc( 100 ); p->vVisited = Vec_PtrAlloc( 100 ); p->nNodeSizeMax = nNodeSizeMax; p->nConeSizeMax = nConeSizeMax; p->fVerbose = fVerbose; // start the BDD manager if ( fUseDcs ) p->dd = Cudd_Init( p->nNodeSizeMax + p->nConeSizeMax, 0, CUDD_UNIQUE_SLOTS, CUDD_CACHE_SLOTS, 0 ); else p->dd = Cudd_Init( p->nNodeSizeMax, 0, CUDD_UNIQUE_SLOTS, CUDD_CACHE_SLOTS, 0 ); Cudd_zddVarsFromBddVars( p->dd, 2 ); return p; } /**Function************************************************************* Synopsis [Stops the resynthesis manager.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void Abc_NtkManRefStop( Abc_ManRef_t * p ) { Extra_StopManager( p->dd ); Vec_PtrFree( p->vVisited ); Vec_StrFree( p->vCube ); free( p ); } /**Function************************************************************* Synopsis [Stops the resynthesis manager.] Description [] SideEffects [] SeeAlso [] ***********************************************************************/ void Abc_NtkManRefPrintStats( Abc_ManRef_t * p ) { printf( "Refactoring statistics:\n" ); printf( "Nodes considered = %8d.\n", p->nNodesConsidered ); printf( "Nodes refactored = %8d.\n", p->nNodesRefactored ); printf( "Calculated gain = %8d.\n", p->nNodesGained ); PRT( "Cuts ", p->timeCut ); PRT( "Resynthesis", p->timeRes ); PRT( " BDD ", p->timeBdd ); PRT( " DCs ", p->timeDcs ); PRT( " SOP ", p->timeSop ); PRT( " FF ", p->timeFact ); PRT( " Eval ", p->timeEval ); PRT( "AIG update ", p->timeNtk ); PRT( "TOTAL ", p->timeTotal ); } //////////////////////////////////////////////////////////////////////// /// END OF FILE /// ////////////////////////////////////////////////////////////////////////