/**CFile****************************************************************
FileName [dchChoice.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Choice computation for tech-mapping.]
Synopsis [Contrustion of choices.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 29, 2008.]
Revision [$Id: dchChoice.c,v 1.00 2008/07/29 00:00:00 alanmi Exp $]
***********************************************************************/
#include "dchInt.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Counts support nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Dch_ObjCountSupp_rec( Aig_Man_t * p, Aig_Obj_t * pObj )
{
int Count;
if ( Aig_ObjIsTravIdCurrent( p, pObj ) )
return 0;
Aig_ObjSetTravIdCurrent( p, pObj );
if ( Aig_ObjIsCi(pObj) )
return 1;
assert( Aig_ObjIsNode(pObj) );
Count = Dch_ObjCountSupp_rec( p, Aig_ObjFanin0(pObj) );
Count += Dch_ObjCountSupp_rec( p, Aig_ObjFanin1(pObj) );
return Count;
}
int Dch_ObjCountSupp( Aig_Man_t * p, Aig_Obj_t * pObj )
{
Aig_ManIncrementTravId( p );
return Dch_ObjCountSupp_rec( p, pObj );
}
/**Function*************************************************************
Synopsis [Counts the number of representatives.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Dch_DeriveChoiceCountReprs( Aig_Man_t * pAig )
{
Aig_Obj_t * pObj, * pRepr;
int i, nReprs = 0;
Aig_ManForEachObj( pAig, pObj, i )
{
pRepr = Aig_ObjRepr( pAig, pObj );
if ( pRepr == NULL )
continue;
assert( pRepr->Id < pObj->Id );
nReprs++;
}
return nReprs;
}
int Dch_DeriveChoiceCountEquivs( Aig_Man_t * pAig )
{
Aig_Obj_t * pObj, * pEquiv;
int i, nEquivs = 0;
Aig_ManForEachObj( pAig, pObj, i )
{
pEquiv = Aig_ObjEquiv( pAig, pObj );
if ( pEquiv == NULL )
continue;
assert( pEquiv->Id < pObj->Id );
nEquivs++;
}
return nEquivs;
}
/**Function*************************************************************
Synopsis [Marks the TFI of the node.]
Description [Returns 1 if there is a CI not marked with previous ID.]
SideEffects []
SeeAlso []
***********************************************************************/
int Dch_ObjMarkTfi_rec( Aig_Man_t * p, Aig_Obj_t * pObj )
{
int RetValue;
if ( pObj == NULL )
return 0;
if ( Aig_ObjIsTravIdCurrent( p, pObj ) )
return 0;
if ( Aig_ObjIsCi(pObj) )
{
RetValue = !Aig_ObjIsTravIdPrevious( p, pObj );
Aig_ObjSetTravIdCurrent( p, pObj );
return RetValue;
}
assert( Aig_ObjIsNode(pObj) );
Aig_ObjSetTravIdCurrent( p, pObj );
RetValue = Dch_ObjMarkTfi_rec( p, Aig_ObjFanin0(pObj) );
RetValue += Dch_ObjMarkTfi_rec( p, Aig_ObjFanin1(pObj) );
// RetValue += Dch_ObjMarkTfi_rec( p, Aig_ObjEquiv(p, pObj) );
return (RetValue > 0);
}
int Dch_ObjCheckSuppRed( Aig_Man_t * p, Aig_Obj_t * pObj, Aig_Obj_t * pRepr )
{
// mark support of the representative node (pRepr)
Aig_ManIncrementTravId( p );
Dch_ObjMarkTfi_rec( p, pRepr );
// detect if the new node (pObj) depends on additional variables
Aig_ManIncrementTravId( p );
if ( Dch_ObjMarkTfi_rec( p, pObj ) )
return 1;//, printf( "1" );
// detect if the representative node (pRepr) depends on additional variables
Aig_ManIncrementTravId( p );
if ( Dch_ObjMarkTfi_rec( p, pRepr ) )
return 1;//, printf( "2" );
// skip the choice if this is what is happening
return 0;
}
/**Function*************************************************************
Synopsis [Make sure reprsentative nodes do not have representatives.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Aig_ManCheckReprs( Aig_Man_t * p )
{
int fPrintConst = 0;
Aig_Obj_t * pObj;
int i, fProb = 0;
int Class0 = 0, ClassCi = 0;
Aig_ManForEachObj( p, pObj, i )
{
if ( Aig_ObjRepr(p, pObj) == NULL )
continue;
if ( !Aig_ObjIsNode(pObj) )
printf( "Obj %d is not an AND but it has a repr %d.\n", i, Aig_ObjId(Aig_ObjRepr(p, pObj)) ), fProb = 1;
else if ( Aig_ObjRepr(p, Aig_ObjRepr(p, pObj)) )
printf( "Obj %d has repr %d with a repr %d.\n", i, Aig_ObjId(Aig_ObjRepr(p, pObj)), Aig_ObjId(Aig_ObjRepr(p, Aig_ObjRepr(p, pObj))) ), fProb = 1;
}
if ( !fProb )
printf( "Representive verification successful.\n" );
else
printf( "Representive verification FAILED.\n" );
if ( !fPrintConst )
return;
// count how many representatives are const0 or a CI
Aig_ManForEachObj( p, pObj, i )
{
if ( Aig_ObjRepr(p, pObj) == Aig_ManConst1(p) )
Class0++;
if ( Aig_ObjRepr(p, pObj) && Aig_ObjIsCi(Aig_ObjRepr(p, pObj)) )
ClassCi++;
}
printf( "Const0 nodes = %d. ConstCI nodes = %d.\n", Class0, ClassCi );
}
/**Function*************************************************************
Synopsis [Verify correctness of choices.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_CheckChoices( Aig_Man_t * p, int fSkipRedSupps )
{
Aig_Obj_t * pObj;
int i, fProb = 0;
Aig_ManCleanMarkA( p );
Aig_ManForEachNode( p, pObj, i )
{
if ( p->pEquivs[i] != NULL )
{
if ( pObj->fMarkA == 1 )
printf( "node %d participates in more than one choice class\n", i ), fProb = 1;
pObj->fMarkA = 1;
// check redundancy
if ( fSkipRedSupps && Dch_ObjCheckSuppRed( p, pObj, p->pEquivs[i]) )
printf( "node %d and repr %d have diff supports\n", pObj->Id, p->pEquivs[i]->Id );
// consider the next one
pObj = p->pEquivs[i];
if ( p->pEquivs[Aig_ObjId(pObj)] == NULL )
{
if ( pObj->fMarkA == 1 )
printf( "repr %d has final node %d participates in more than one choice class\n", i, pObj->Id ), fProb = 1;
pObj->fMarkA = 1;
}
// consider the non-head ones
if ( pObj->nRefs > 0 )
printf( "node %d belonging to choice has fanout %d\n", pObj->Id, pObj->nRefs );
}
if ( p->pReprs && p->pReprs[i] != NULL )
{
if ( pObj->nRefs > 0 )
printf( "node %d has representative %d and fanout count %d\n", pObj->Id, p->pReprs[i]->Id, pObj->nRefs ), fProb = 1;
}
}
Aig_ManCleanMarkA( p );
if ( !fProb )
printf( "Verification of choice AIG succeeded.\n" );
else
printf( "Verification of choice AIG FAILED.\n" );
}
/**Function*************************************************************
Synopsis [Checks for combinational loops in the AIG.]
Description [Returns 1 if combinational loop is detected.]
SideEffects []
SeeAlso []
***********************************************************************/
int Aig_ManCheckAcyclic_rec( Aig_Man_t * p, Aig_Obj_t * pNode, int fVerbose )
{
Aig_Obj_t * pFanin;
int fAcyclic;
if ( Aig_ObjIsCi(pNode) || Aig_ObjIsConst1(pNode) )
return 1;
assert( Aig_ObjIsNode(pNode) );
// make sure the node is not visited
assert( !Aig_ObjIsTravIdPrevious(p, pNode) );
// check if the node is part of the combinational loop
if ( Aig_ObjIsTravIdCurrent(p, pNode) )
{
if ( fVerbose )
Abc_Print( 1, "Network \"%s\" contains combinational loop!\n", p->pSpec? p->pSpec : NULL );
if ( fVerbose )
Abc_Print( 1, "Node \"%d\" is encountered twice on the following path to the COs:\n", Aig_ObjId(pNode) );
return 0;
}
// mark this node as a node on the current path
Aig_ObjSetTravIdCurrent( p, pNode );
// visit the transitive fanin
pFanin = Aig_ObjFanin0(pNode);
// check if the fanin is visited
if ( !Aig_ObjIsTravIdPrevious(p, pFanin) )
{
// traverse the fanin's cone searching for the loop
if ( !(fAcyclic = Aig_ManCheckAcyclic_rec(p, pFanin, fVerbose)) )
{
// return as soon as the loop is detected
if ( fVerbose )
Abc_Print( 1, " %d ->", Aig_ObjId(pFanin) );
return 0;
}
}
// visit the transitive fanin
pFanin = Aig_ObjFanin1(pNode);
// check if the fanin is visited
if ( !Aig_ObjIsTravIdPrevious(p, pFanin) )
{
// traverse the fanin's cone searching for the loop
if ( !(fAcyclic = Aig_ManCheckAcyclic_rec(p, pFanin, fVerbose)) )
{
// return as soon as the loop is detected
if ( fVerbose )
Abc_Print( 1, " %d ->", Aig_ObjId(pFanin) );
return 0;
}
}
// visit choices
if ( Aig_ObjRepr(p, pNode) == NULL && Aig_ObjEquiv(p, pNode) != NULL )
{
for ( pFanin = Aig_ObjEquiv(p, pNode); pFanin; pFanin = Aig_ObjEquiv(p, pFanin) )
{
// check if the fanin is visited
if ( Aig_ObjIsTravIdPrevious(p, pFanin) )
continue;
// traverse the fanin's cone searching for the loop
if ( (fAcyclic = Aig_ManCheckAcyclic_rec(p, pFanin, fVerbose)) )
continue;
// return as soon as the loop is detected
if ( fVerbose )
Abc_Print( 1, " %d", Aig_ObjId(pFanin) );
if ( fVerbose )
Abc_Print( 1, " (choice of %d) -> ", Aig_ObjId(pNode) );
return 0;
}
}
// mark this node as a visited node
Aig_ObjSetTravIdPrevious( p, pNode );
return 1;
}
int Aig_ManCheckAcyclic( Aig_Man_t * p, int fVerbose )
{
Aig_Obj_t * pNode;
int fAcyclic;
int i;
// set the traversal ID for this DFS ordering
Aig_ManIncrementTravId( p );
Aig_ManIncrementTravId( p );
// pNode->TravId == pNet->nTravIds means "pNode is on the path"
// pNode->TravId == pNet->nTravIds - 1 means "pNode is visited but is not on the path"
// pNode->TravId < pNet->nTravIds - 1 means "pNode is not visited"
// traverse the network to detect cycles
fAcyclic = 1;
Aig_ManForEachCo( p, pNode, i )
{
pNode = Aig_ObjFanin0(pNode);
if ( Aig_ObjIsTravIdPrevious(p, pNode) )
continue;
// traverse the output logic cone
if ( (fAcyclic = Aig_ManCheckAcyclic_rec(p, pNode, fVerbose)) )
continue;
// stop as soon as the first loop is detected
if ( fVerbose )
Abc_Print( 1, " CO %d\n", i );
break;
}
return fAcyclic;
}
/**Function*************************************************************
Synopsis [Returns 1 if the choice node of pRepr is in the TFI of pObj.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Dch_ObjCheckTfi_rec( Aig_Man_t * p, Aig_Obj_t * pObj )
{
// check the trivial cases
if ( pObj == NULL )
return 0;
if ( Aig_ObjIsCi(pObj) )
return 0;
if ( pObj->fMarkA )
return 1;
// skip the visited node
if ( Aig_ObjIsTravIdCurrent( p, pObj ) )
return 0;
Aig_ObjSetTravIdCurrent( p, pObj );
// check the children
if ( Dch_ObjCheckTfi_rec( p, Aig_ObjFanin0(pObj) ) )
return 1;
if ( Dch_ObjCheckTfi_rec( p, Aig_ObjFanin1(pObj) ) )
return 1;
// check equivalent nodes
return Dch_ObjCheckTfi_rec( p, Aig_ObjEquiv(p, pObj) );
}
int Dch_ObjCheckTfi( Aig_Man_t * p, Aig_Obj_t * pObj, Aig_Obj_t * pRepr )
{
Aig_Obj_t * pTemp;
int RetValue;
assert( !Aig_IsComplement(pObj) );
assert( !Aig_IsComplement(pRepr) );
// mark nodes of the choice node
for ( pTemp = pRepr; pTemp; pTemp = Aig_ObjEquiv(p, pTemp) )
pTemp->fMarkA = 1;
// traverse the new node
Aig_ManIncrementTravId( p );
RetValue = Dch_ObjCheckTfi_rec( p, pObj );
// unmark nodes of the choice node
for ( pTemp = pRepr; pTemp; pTemp = Aig_ObjEquiv(p, pTemp) )
pTemp->fMarkA = 0;
return RetValue;
}
/**Function*************************************************************
Synopsis [Returns representatives of fanin in approapriate polarity.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline Aig_Obj_t * Aig_ObjGetRepr( Aig_Man_t * p, Aig_Obj_t * pObj )
{
Aig_Obj_t * pRepr;
if ( (pRepr = Aig_ObjRepr(p, Aig_Regular(pObj))) )
return Aig_NotCond( pRepr, Aig_Regular(pObj)->fPhase ^ pRepr->fPhase ^ Aig_IsComplement(pObj) );
return pObj;
}
static inline Aig_Obj_t * Aig_ObjChild0CopyRepr( Aig_Man_t * p, Aig_Obj_t * pObj ) { return Aig_ObjGetRepr( p, Aig_ObjChild0Copy(pObj) ); }
static inline Aig_Obj_t * Aig_ObjChild1CopyRepr( Aig_Man_t * p, Aig_Obj_t * pObj ) { return Aig_ObjGetRepr( p, Aig_ObjChild1Copy(pObj) ); }
/**Function*************************************************************
Synopsis [Derives the AIG with choices from representatives.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Dch_DeriveChoiceAigNode( Aig_Man_t * pAigNew, Aig_Man_t * pAigOld, Aig_Obj_t * pObj, int fSkipRedSupps )
{
Aig_Obj_t * pRepr, * pObjNew, * pReprNew;
assert( !Aig_IsComplement(pObj) );
// get the representative
pRepr = Aig_ObjRepr( pAigOld, pObj );
if ( pRepr != NULL && (Aig_ObjIsConst1(pRepr) || Aig_ObjIsCi(pRepr)) )
{
assert( pRepr->pData != NULL );
pObj->pData = Aig_NotCond( (Aig_Obj_t *)pRepr->pData, pObj->fPhase ^ pRepr->fPhase );
return;
}
// get the new node
pObjNew = Aig_And( pAigNew,
Aig_ObjChild0CopyRepr(pAigNew, pObj),
Aig_ObjChild1CopyRepr(pAigNew, pObj) );
pObjNew = Aig_ObjGetRepr( pAigNew, pObjNew );
// assert( Aig_ObjRepr( pAigNew, pObjNew ) == NULL );
// assign the copy
assert( pObj->pData == NULL );
pObj->pData = pObjNew;
// skip those without reprs
if ( pRepr == NULL )
return;
assert( pRepr->Id < pObj->Id );
assert( Aig_ObjIsNode(pRepr) );
// get the corresponding new nodes
pObjNew = Aig_Regular((Aig_Obj_t *)pObj->pData);
pReprNew = Aig_Regular((Aig_Obj_t *)pRepr->pData);
// skip earlier nodes
if ( pReprNew->Id >= pObjNew->Id )
return;
assert( pReprNew->Id < pObjNew->Id );
// set the representatives
Aig_ObjSetRepr( pAigNew, pObjNew, pReprNew );
// skip used nodes
if ( pObjNew->nRefs > 0 )
return;
assert( pObjNew->nRefs == 0 );
// skip choices that can lead to combo loops
if ( Dch_ObjCheckTfi( pAigNew, pObjNew, pReprNew ) )
return;
// don't add choice if structural support of pObjNew and pReprNew differ
if ( fSkipRedSupps && Dch_ObjCheckSuppRed(pAigNew, pObjNew, pReprNew) )
return;
// add choice to the end of the list
while ( pAigNew->pEquivs[pReprNew->Id] != NULL )
pReprNew = pAigNew->pEquivs[pReprNew->Id];
assert( pAigNew->pEquivs[pReprNew->Id] == NULL );
pAigNew->pEquivs[pReprNew->Id] = pObjNew;
}
Aig_Man_t * Dch_DeriveChoiceAigInt( Aig_Man_t * pAig, int fSkipRedSupps )
{
Aig_Man_t * pChoices;
Aig_Obj_t * pObj;
int i;
// start recording equivalences
pChoices = Aig_ManStart( Aig_ManObjNumMax(pAig) );
pChoices->pEquivs = ABC_CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(pAig) );
pChoices->pReprs = ABC_CALLOC( Aig_Obj_t *, Aig_ManObjNumMax(pAig) );
// map constants and PIs
Aig_ManCleanData( pAig );
Aig_ManConst1(pAig)->pData = Aig_ManConst1(pChoices);
Aig_ManForEachCi( pAig, pObj, i )
pObj->pData = Aig_ObjCreateCi( pChoices );
// construct choices for the internal nodes
assert( pAig->pReprs != NULL );
Aig_ManForEachNode( pAig, pObj, i )
Dch_DeriveChoiceAigNode( pChoices, pAig, pObj, fSkipRedSupps );
Aig_ManForEachCo( pAig, pObj, i )
Aig_ObjCreateCo( pChoices, Aig_ObjChild0CopyRepr(pChoices, pObj) );
Aig_ManSetRegNum( pChoices, Aig_ManRegNum(pAig) );
return pChoices;
}
Aig_Man_t * Dch_DeriveChoiceAig( Aig_Man_t * pAig, int fSkipRedSupps )
{
int fCheck = 0;
Aig_Man_t * pChoices, * pTemp;
// verify
if ( fCheck )
Aig_ManCheckReprs( pAig );
// compute choices
pChoices = Dch_DeriveChoiceAigInt( pAig, fSkipRedSupps );
ABC_FREE( pChoices->pReprs );
// verify
if ( fCheck )
Dch_CheckChoices( pChoices, fSkipRedSupps );
// find correct topo order with choices
pChoices = Aig_ManDupDfs( pTemp = pChoices );
Aig_ManStop( pTemp );
// verify
if ( fCheck )
Dch_CheckChoices( pChoices, fSkipRedSupps );
return pChoices;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END