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/**CFile****************************************************************
FileName [ivyDfs.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [And-Inverter Graph package.]
Synopsis [DFS collection procedures.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - May 11, 2006.]
Revision [$Id: ivyDfs.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]
***********************************************************************/
#include "ivy.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Collects nodes in the DFS order.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManDfs_rec( Ivy_Man_t * p, Ivy_Obj_t * pObj, Vec_Int_t * vNodes )
{
if ( Ivy_ObjIsMarkA(pObj) )
return;
Ivy_ObjSetMarkA(pObj);
if ( Ivy_ObjIsConst1(pObj) || Ivy_ObjIsCi(pObj) )
{
if ( p->pHaig == NULL && pObj->pEquiv )
Ivy_ManDfs_rec( p, Ivy_Regular(pObj->pEquiv), vNodes );
return;
}
//printf( "visiting node %d\n", pObj->Id );
/*
if ( pObj->Id == 87 || pObj->Id == 90 )
{
int y = 0;
}
*/
assert( Ivy_ObjIsBuf(pObj) || Ivy_ObjIsAnd(pObj) || Ivy_ObjIsExor(pObj) );
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
if ( !Ivy_ObjIsBuf(pObj) )
Ivy_ManDfs_rec( p, Ivy_ObjFanin1(pObj), vNodes );
if ( p->pHaig == NULL && pObj->pEquiv )
Ivy_ManDfs_rec( p, Ivy_Regular(pObj->pEquiv), vNodes );
Vec_IntPush( vNodes, pObj->Id );
//printf( "adding node %d with fanins %d and %d and equiv %d (refs = %d)\n",
// pObj->Id, Ivy_ObjFanin0(pObj)->Id, Ivy_ObjFanin1(pObj)->Id,
// pObj->pEquiv? Ivy_Regular(pObj->pEquiv)->Id: -1, Ivy_ObjRefs(pObj) );
}
/**Function*************************************************************
Synopsis [Collects AND/EXOR nodes in the DFS order from CIs to COs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Ivy_ManDfs( Ivy_Man_t * p )
{
Vec_Int_t * vNodes;
Ivy_Obj_t * pObj;
int i;
assert( Ivy_ManLatchNum(p) == 0 );
// make sure the nodes are not marked
Ivy_ManForEachObj( p, pObj, i )
assert( !pObj->fMarkA && !pObj->fMarkB );
// collect the nodes
vNodes = Vec_IntAlloc( Ivy_ManNodeNum(p) );
Ivy_ManForEachPo( p, pObj, i )
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
// unmark the collected nodes
// Ivy_ManForEachNodeVec( p, vNodes, pObj, i )
// Ivy_ObjClearMarkA(pObj);
Ivy_ManForEachObj( p, pObj, i )
Ivy_ObjClearMarkA(pObj);
// make sure network does not have dangling nodes
assert( Vec_IntSize(vNodes) == Ivy_ManNodeNum(p) + Ivy_ManBufNum(p) );
return vNodes;
}
/**Function*************************************************************
Synopsis [Collects AND/EXOR nodes in the DFS order from CIs to COs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Ivy_ManDfsSeq( Ivy_Man_t * p, Vec_Int_t ** pvLatches )
{
Vec_Int_t * vNodes, * vLatches;
Ivy_Obj_t * pObj;
int i;
// assert( Ivy_ManLatchNum(p) > 0 );
// make sure the nodes are not marked
Ivy_ManForEachObj( p, pObj, i )
assert( !pObj->fMarkA && !pObj->fMarkB );
// collect the latches
vLatches = Vec_IntAlloc( Ivy_ManLatchNum(p) );
Ivy_ManForEachLatch( p, pObj, i )
Vec_IntPush( vLatches, pObj->Id );
// collect the nodes
vNodes = Vec_IntAlloc( Ivy_ManNodeNum(p) );
Ivy_ManForEachPo( p, pObj, i )
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
Ivy_ManForEachNodeVec( p, vLatches, pObj, i )
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
// unmark the collected nodes
// Ivy_ManForEachNodeVec( p, vNodes, pObj, i )
// Ivy_ObjClearMarkA(pObj);
Ivy_ManForEachObj( p, pObj, i )
Ivy_ObjClearMarkA(pObj);
// make sure network does not have dangling nodes
// assert( Vec_IntSize(vNodes) == Ivy_ManNodeNum(p) + Ivy_ManBufNum(p) );
// temporary!!!
if ( pvLatches == NULL )
Vec_IntFree( vLatches );
else
*pvLatches = vLatches;
return vNodes;
}
/**Function*************************************************************
Synopsis [Collects nodes in the cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManCollectCone_rec( Ivy_Obj_t * pObj, Vec_Ptr_t * vCone )
{
if ( pObj->fMarkA )
return;
if ( Ivy_ObjIsBuf(pObj) )
{
Ivy_ManCollectCone_rec( Ivy_ObjFanin0(pObj), vCone );
Vec_PtrPush( vCone, pObj );
return;
}
assert( Ivy_ObjIsNode(pObj) );
Ivy_ManCollectCone_rec( Ivy_ObjFanin0(pObj), vCone );
Ivy_ManCollectCone_rec( Ivy_ObjFanin1(pObj), vCone );
Vec_PtrPushUnique( vCone, pObj );
}
/**Function*************************************************************
Synopsis [Collects nodes in the cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManCollectCone( Ivy_Obj_t * pObj, Vec_Ptr_t * vFront, Vec_Ptr_t * vCone )
{
Ivy_Obj_t * pTemp;
int i;
assert( !Ivy_IsComplement(pObj) );
assert( Ivy_ObjIsNode(pObj) );
// mark the nodes
Vec_PtrForEachEntry( vFront, pTemp, i )
Ivy_Regular(pTemp)->fMarkA = 1;
assert( pObj->fMarkA == 0 );
// collect the cone
Vec_PtrClear( vCone );
Ivy_ManCollectCone_rec( pObj, vCone );
// unmark the nodes
Vec_PtrForEachEntry( vFront, pTemp, i )
Ivy_Regular(pTemp)->fMarkA = 0;
}
/**Function*************************************************************
Synopsis [Returns the nodes by level.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Vec_t * Ivy_ManLevelize( Ivy_Man_t * p )
{
Vec_Vec_t * vNodes;
Ivy_Obj_t * pObj;
int i;
vNodes = Vec_VecAlloc( 100 );
Ivy_ManForEachObj( p, pObj, i )
{
assert( !Ivy_ObjIsBuf(pObj) );
if ( Ivy_ObjIsNode(pObj) )
Vec_VecPush( vNodes, pObj->Level, pObj );
}
return vNodes;
}
/**Function*************************************************************
Synopsis [Computes required levels for each node.]
Description [Assumes topological ordering of the nodes.]
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Ivy_ManRequiredLevels( Ivy_Man_t * p )
{
Ivy_Obj_t * pObj;
Vec_Int_t * vLevelsR;
Vec_Vec_t * vNodes;
int i, k, Level, LevelMax;
assert( p->vRequired == NULL );
// start the required times
vLevelsR = Vec_IntStart( Ivy_ManObjIdMax(p) + 1 );
// iterate through the nodes in the reverse order
vNodes = Ivy_ManLevelize( p );
Vec_VecForEachEntryReverseReverse( vNodes, pObj, i, k )
{
Level = Vec_IntEntry( vLevelsR, pObj->Id ) + 1 + Ivy_ObjIsExor(pObj);
if ( Vec_IntEntry( vLevelsR, Ivy_ObjFaninId0(pObj) ) < Level )
Vec_IntWriteEntry( vLevelsR, Ivy_ObjFaninId0(pObj), Level );
if ( Vec_IntEntry( vLevelsR, Ivy_ObjFaninId1(pObj) ) < Level )
Vec_IntWriteEntry( vLevelsR, Ivy_ObjFaninId1(pObj), Level );
}
Vec_VecFree( vNodes );
// convert it into the required times
LevelMax = Ivy_ManLevels( p );
//printf( "max %5d\n",LevelMax );
Ivy_ManForEachObj( p, pObj, i )
{
Level = Vec_IntEntry( vLevelsR, pObj->Id );
Vec_IntWriteEntry( vLevelsR, pObj->Id, LevelMax - Level );
//printf( "%5d : %5d %5d\n", pObj->Id, Level, LevelMax - Level );
}
p->vRequired = vLevelsR;
return vLevelsR;
}
/**Function*************************************************************
Synopsis [Recursively detects combinational loops.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManIsAcyclic_rec( Ivy_Man_t * p, Ivy_Obj_t * pObj )
{
// skip the node if it is already visited
if ( Ivy_ObjIsTravIdPrevious(p, pObj) )
return 1;
// check if the node is part of the combinational loop
if ( Ivy_ObjIsTravIdCurrent(p, pObj) )
{
fprintf( stdout, "Manager contains combinational loop!\n" );
fprintf( stdout, "Node \"%d\" is encountered twice on the following path:\n", Ivy_ObjId(pObj) );
fprintf( stdout, " %d", Ivy_ObjId(pObj) );
return 0;
}
// mark this node as a node on the current path
Ivy_ObjSetTravIdCurrent( p, pObj );
// explore equivalent nodes if pObj is the main node
if ( p->pHaig == NULL && pObj->pEquiv && Ivy_ObjRefs(pObj) > 0 )
{
Ivy_Obj_t * pTemp;
assert( !Ivy_IsComplement(pObj->pEquiv) );
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
{
// traverse the fanin's cone searching for the loop
if ( !Ivy_ManIsAcyclic_rec(p, pTemp) )
{
// return as soon as the loop is detected
fprintf( stdout, " -> (%d", Ivy_ObjId(pObj) );
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
fprintf( stdout, " %d", Ivy_ObjId(pTemp) );
fprintf( stdout, ")" );
return 0;
}
}
}
// quite if it is a CI node
if ( Ivy_ObjIsCi(pObj) || Ivy_ObjIsConst1(pObj) )
{
// mark this node as a visited node
Ivy_ObjSetTravIdPrevious( p, pObj );
return 1;
}
assert( Ivy_ObjIsNode(pObj) || Ivy_ObjIsBuf(pObj) );
// traverse the fanin's cone searching for the loop
if ( !Ivy_ManIsAcyclic_rec(p, Ivy_ObjFanin0(pObj)) )
{
// return as soon as the loop is detected
fprintf( stdout, " -> %d", Ivy_ObjId(pObj) );
return 0;
}
// traverse the fanin's cone searching for the loop
if ( Ivy_ObjIsNode(pObj) && !Ivy_ManIsAcyclic_rec(p, Ivy_ObjFanin1(pObj)) )
{
// return as soon as the loop is detected
fprintf( stdout, " -> %d", Ivy_ObjId(pObj) );
return 0;
}
// mark this node as a visited node
Ivy_ObjSetTravIdPrevious( p, pObj );
return 1;
}
/**Function*************************************************************
Synopsis [Detects combinational loops.]
Description [This procedure is based on the idea suggested by Donald Chai.
As we traverse the network and visit the nodes, we need to distinquish
three types of nodes: (1) those that are visited for the first time,
(2) those that have been visited in this traversal but are currently not
on the traversal path, (3) those that have been visited and are currently
on the travesal path. When the node of type (3) is encountered, it means
that there is a combinational loop. To mark the three types of nodes,
two new values of the traversal IDs are used.]
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManIsAcyclic( Ivy_Man_t * p )
{
Ivy_Obj_t * pObj;
int fAcyclic, i;
// set the traversal ID for this DFS ordering
Ivy_ManIncrementTravId( p );
Ivy_ManIncrementTravId( p );
// pObj->TravId == pNet->nTravIds means "pObj is on the path"
// pObj->TravId == pNet->nTravIds - 1 means "pObj is visited but is not on the path"
// pObj->TravId < pNet->nTravIds - 1 means "pObj is not visited"
// traverse the network to detect cycles
fAcyclic = 1;
Ivy_ManForEachCo( p, pObj, i )
{
// traverse the output logic cone
if ( (fAcyclic = Ivy_ManIsAcyclic_rec(p, Ivy_ObjFanin0(pObj))) )
continue;
// stop as soon as the first loop is detected
fprintf( stdout, " (cone of %s \"%d\")\n", Ivy_ObjIsLatch(pObj)? "latch" : "PO", Ivy_ObjId(pObj) );
break;
}
return fAcyclic;
}
/**Function*************************************************************
Synopsis [Sets the levels of the nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManSetLevels_rec( Ivy_Obj_t * pObj, int fHaig )
{
// quit if the node is visited
if ( Ivy_ObjIsMarkA(pObj) )
return pObj->Level;
Ivy_ObjSetMarkA(pObj);
// quit if this is a CI
if ( Ivy_ObjIsConst1(pObj) || Ivy_ObjIsCi(pObj) )
return 0;
assert( Ivy_ObjIsBuf(pObj) || Ivy_ObjIsAnd(pObj) || Ivy_ObjIsExor(pObj) );
// get levels of the fanins
Ivy_ManSetLevels_rec( Ivy_ObjFanin0(pObj), fHaig );
if ( !Ivy_ObjIsBuf(pObj) )
Ivy_ManSetLevels_rec( Ivy_ObjFanin1(pObj), fHaig );
// get level of the node
if ( Ivy_ObjIsBuf(pObj) )
pObj->Level = 1 + Ivy_ObjFanin0(pObj)->Level;
else if ( Ivy_ObjIsNode(pObj) )
pObj->Level = Ivy_ObjLevelNew( pObj );
else assert( 0 );
// get level of other choices
if ( fHaig && pObj->pEquiv && Ivy_ObjRefs(pObj) > 0 )
{
Ivy_Obj_t * pTemp;
unsigned LevelMax = pObj->Level;
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
{
Ivy_ManSetLevels_rec( pTemp, fHaig );
LevelMax = IVY_MAX( LevelMax, pTemp->Level );
}
// get this level
pObj->Level = LevelMax;
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
pTemp->Level = LevelMax;
}
return pObj->Level;
}
/**Function*************************************************************
Synopsis [Sets the levels of the nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManSetLevels( Ivy_Man_t * p, int fHaig )
{
Ivy_Obj_t * pObj;
int i, LevelMax;
// check if CIs have choices
if ( fHaig )
{
Ivy_ManForEachCi( p, pObj, i )
if ( pObj->pEquiv )
printf( "CI %d has a choice, which will not be visualized.\n", pObj->Id );
}
// clean the levels
Ivy_ManForEachObj( p, pObj, i )
pObj->Level = 0;
// compute the levels
LevelMax = 0;
Ivy_ManForEachCo( p, pObj, i )
{
Ivy_ManSetLevels_rec( Ivy_ObjFanin0(pObj), fHaig );
LevelMax = IVY_MAX( LevelMax, (int)Ivy_ObjFanin0(pObj)->Level );
}
// compute levels of nodes without fanout
Ivy_ManForEachObj( p, pObj, i )
if ( (Ivy_ObjIsNode(pObj) || Ivy_ObjIsBuf(pObj)) && Ivy_ObjRefs(pObj) == 0 )
{
Ivy_ManSetLevels_rec( pObj, fHaig );
LevelMax = IVY_MAX( LevelMax, (int)pObj->Level );
}
// clean the marks
Ivy_ManForEachObj( p, pObj, i )
Ivy_ObjClearMarkA(pObj);
return LevelMax;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
