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/**CFile****************************************************************
FileName [ivyRewrite.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [And-Inverter Graph package.]
Synopsis [AIG rewriting.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - May 11, 2006.]
Revision [$Id: ivyRewrite.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]
***********************************************************************/
#include "ivy.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static unsigned Ivy_ManSeqFindTruth( Ivy_Obj_t * pNode, Vec_Int_t * vFront );
static void Ivy_ManSeqCollectCone( Ivy_Obj_t * pNode, Vec_Int_t * vCone );
static int Ivy_ManSeqGetCost( Ivy_Man_t * p, Vec_Int_t * vCone );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs Boolean rewriting of sequential AIG.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManSeqRewrite( Ivy_Man_t * p, int fUpdateLevel, int fUseZeroCost )
{
Vec_Int_t * vNodes, * vFront, * vInside, * vTree;
Ivy_Obj_t * pNode, * pNodeNew, * pTemp;
int i, k, nCostOld, nCostInt, nCostInt2, nCostNew, RetValue, Entry, nRefsSaved, nInputs;
int clk, clkCut = 0, clkTru = 0, clkDsd = 0, clkUpd = 0, clkStart = clock();
unsigned uTruth;
nInputs = 4;
vTree = Vec_IntAlloc( 8 );
vFront = Vec_IntAlloc( 8 );
vInside = Vec_IntAlloc( 50 );
vNodes = Ivy_ManDfs( p );
Ivy_ManForEachNodeVec( p, vNodes, pNode, i )
{
if ( Ivy_ObjIsBuf(pNode) )
continue;
// fix the fanin buffer problem
Ivy_NodeFixBufferFanins( pNode );
if ( Ivy_ObjIsBuf(pNode) )
continue;
// find one sequential cut rooted at this node
clk = clock();
Ivy_ManSeqFindCut( pNode, vFront, vInside, nInputs );
clkCut += clock() - clk;
// compute the truth table of the cut
clk = clock();
uTruth = Ivy_ManSeqFindTruth( pNode, vFront );
clkTru += clock() - clk;
// decompose the truth table
clk = clock();
RetValue = Ivy_TruthDsd( uTruth, vTree );
clkDsd += clock() - clk;
if ( !RetValue )
continue; // DSD does not exist
// Ivy_TruthDsdPrint( stdout, vTree );
clk = clock();
// remember the cost of the current network
nCostOld = Ivy_ManGetCost(p);
// increment references of the cut variables
Vec_IntForEachEntry( vFront, Entry, k )
{
pTemp = Ivy_ManObj(p, Ivy_LeafId(Entry));
Ivy_ObjRefsInc( pTemp );
}
// dereference and record undo
nRefsSaved = pNode->nRefs; pNode->nRefs = 0;
Ivy_ManUndoStart( p );
Ivy_ObjDelete_rec( pNode, 0 );
Ivy_ManUndoStop( p );
pNode->nRefs = nRefsSaved;
// get the intermediate cost
nCostInt = Ivy_ManGetCost(p);
// printf( "Removed by dereferencing = %d.\n", nCostOld - nCostInt );
// construct the new logic cone
pNodeNew = Ivy_ManDsdConstruct( p, vFront, vTree );
// remember the cost
nCostNew = Ivy_ManGetCost(p);
// printf( "Added by dereferencing = %d.\n", nCostInt - nCostNew );
// nCostNew = nCostNew;
/*
if ( Ivy_Regular(pNodeNew)->nRefs == 0 )
Ivy_ObjDelete_rec( Ivy_Regular(pNodeNew), 1 );
// get the intermediate cost
nCostInt2 = Ivy_ManGetCost(p);
assert( nCostInt == nCostInt2 );
Ivy_ManUndoPerform( p, pNode );
pNode->nRefs = nRefsSaved;
Vec_IntForEachEntry( vFront, Entry, k )
{
// pTemp = Ivy_ManObj(p, Ivy_LeafId(Entry));
pTemp = Ivy_ManObj(p, Entry);
Ivy_ObjRefsDec( pTemp );
}
clkUpd += clock() - clk;
continue;
*/
// detect the case when they are exactly the same
// if ( pNodeNew == pNode )
// continue;
// compare the costs
if ( nCostOld > nCostNew || nCostOld == nCostNew && fUseZeroCost )
{ // accept the change
// printf( "NODES GAINED = %d\n", nCostOld - nCostNew );
Ivy_ObjReplace( pNode, pNodeNew, 0, 1 );
pNode->nRefs = nRefsSaved;
}
else
{ // reject change
// printf( "Rejected\n" );
if ( Ivy_Regular(pNodeNew)->nRefs == 0 )
Ivy_ObjDelete_rec( Ivy_Regular(pNodeNew), 1 );
// get the intermediate cost
nCostInt2 = Ivy_ManGetCost(p);
assert( nCostInt == nCostInt2 );
// reconstruct the old node
Ivy_ManUndoPerform( p, pNode );
pNode->nRefs = nRefsSaved;
}
// decrement references of the cut variables
Vec_IntForEachEntry( vFront, Entry, k )
{
// pTemp = Ivy_ManObj(p, Ivy_LeafId(Entry));
pTemp = Ivy_ManObj(p, Entry);
if ( Ivy_ObjIsNone(pTemp) )
continue;
Ivy_ObjRefsDec( pTemp );
if ( Ivy_ObjRefs(pTemp) == 0 )
Ivy_ObjDelete_rec( pTemp, 1 );
}
clkUpd += clock() - clk;
}
PRT( "Cut ", clkCut );
PRT( "Truth ", clkTru );
PRT( "DSD ", clkDsd );
PRT( "Update ", clkUpd );
PRT( "TOTAL ", clock() - clkStart );
Vec_IntFree( vTree );
Vec_IntFree( vFront );
Vec_IntFree( vInside );
Vec_IntFree( vNodes );
if ( !Ivy_ManCheck(p) )
{
printf( "Ivy_ManSeqRewrite(): The check has failed.\n" );
}
return 1;
}
/**Function*************************************************************
Synopsis [Computes the truth table of the sequential cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
unsigned Ivy_ManSeqFindTruth_rec( Ivy_Man_t * p, unsigned Node, Vec_Int_t * vFront )
{
static unsigned uMasks[5] = { 0xAAAAAAAA, 0xCCCCCCCC, 0xF0F0F0F0, 0xFF00FF00, 0xFFFF0000 };
unsigned uTruth0, uTruth1;
Ivy_Obj_t * pNode;
int nLatches, Number;
// consider the case of a constant
if ( Node == 0 )
return ~((unsigned)0);
// try to find this node in the frontier
Number = Vec_IntFind( vFront, Node );
if ( Number >= 0 )
return uMasks[Number];
// get the node
pNode = Ivy_ManObj( p, Ivy_LeafId(Node) );
assert( !Ivy_ObjIsPi(pNode) && !Ivy_ObjIsConst1(pNode) );
// get the number of latches
nLatches = Ivy_LeafLat(Node) + Ivy_ObjIsLatch(pNode);
// expand the first fanin
uTruth0 = Ivy_ManSeqFindTruth_rec( p, Ivy_LeafCreate(Ivy_ObjFaninId0(pNode), nLatches), vFront );
if ( Ivy_ObjFaninC0(pNode) )
uTruth0 = ~uTruth0;
// quit if this is the one fanin node
if ( Ivy_ObjIsLatch(pNode) || Ivy_ObjIsBuf(pNode) )
return uTruth0;
assert( Ivy_ObjIsNode(pNode) );
// expand the second fanin
uTruth1 = Ivy_ManSeqFindTruth_rec( p, Ivy_LeafCreate(Ivy_ObjFaninId1(pNode), nLatches), vFront );
if ( Ivy_ObjFaninC1(pNode) )
uTruth1 = ~uTruth1;
// return the truth table
return Ivy_ObjIsAnd(pNode)? uTruth0 & uTruth1 : uTruth0 ^ uTruth1;
}
/**Function*************************************************************
Synopsis [Computes the truth table of the sequential cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
unsigned Ivy_ManSeqFindTruth( Ivy_Obj_t * pNode, Vec_Int_t * vFront )
{
assert( Ivy_ObjIsNode(pNode) );
return Ivy_ManSeqFindTruth_rec( Ivy_ObjMan(pNode), Ivy_LeafCreate(pNode->Id, 0), vFront );
}
/**Function*************************************************************
Synopsis [Recursively dereferences the node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManSeqDeref_rec( Ivy_Obj_t * pNode, Vec_Int_t * vCone )
{
Ivy_Obj_t * pFan;
assert( !Ivy_IsComplement(pNode) );
assert( !Ivy_ObjIsNone(pNode) );
if ( Ivy_ObjIsPi(pNode) )
return;
// deref the first fanin
pFan = Ivy_ObjFanin0(pNode);
Ivy_ObjRefsDec( pFan );
if ( Ivy_ObjRefs( pFan ) == 0 )
Ivy_ManSeqDeref_rec( pFan, vCone );
// deref the second fanin
pFan = Ivy_ObjFanin1(pNode);
Ivy_ObjRefsDec( pFan );
if ( Ivy_ObjRefs( pFan ) == 0 )
Ivy_ManSeqDeref_rec( pFan, vCone );
// save the node
Vec_IntPush( vCone, pNode->Id );
}
/**Function*************************************************************
Synopsis [Recursively references the node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManSeqRef_rec( Ivy_Obj_t * pNode )
{
Ivy_Obj_t * pFan;
assert( !Ivy_IsComplement(pNode) );
assert( !Ivy_ObjIsNone(pNode) );
if ( Ivy_ObjIsPi(pNode) )
return;
// ref the first fanin
pFan = Ivy_ObjFanin0(pNode);
if ( Ivy_ObjRefs( pFan ) == 0 )
Ivy_ManSeqRef_rec( pFan );
Ivy_ObjRefsInc( pFan );
// ref the second fanin
pFan = Ivy_ObjFanin1(pNode);
if ( Ivy_ObjRefs( pFan ) == 0 )
Ivy_ManSeqRef_rec( pFan );
Ivy_ObjRefsInc( pFan );
}
/**Function*************************************************************
Synopsis [Collect MFFC of the node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManSeqCollectCone( Ivy_Obj_t * pNode, Vec_Int_t * vCone )
{
Vec_IntClear( vCone );
Ivy_ManSeqDeref_rec( pNode, vCone );
Ivy_ManSeqRef_rec( pNode );
}
/**Function*************************************************************
Synopsis [Computes the cost of the logic cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManSeqGetCost( Ivy_Man_t * p, Vec_Int_t * vCone )
{
Ivy_Obj_t * pObj;
int i, Cost = 0;
Ivy_ManForEachNodeVec( p, vCone, pObj, i )
{
if ( Ivy_ObjIsAnd(pObj) )
Cost += 1;
else if ( Ivy_ObjIsExor(pObj) )
Cost += 2;
}
return 0;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
