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/**CFile****************************************************************
FileName [giaRetime.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Scalable AIG package.]
Synopsis [Performs most-forward retiming for AIG with flop classes.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: giaRetime.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "gia.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Marks objects reachables from Const0 and PIs/
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Gia_ManMarkAutonomous_rec( Gia_Man_t * p, Gia_Obj_t * pObj )
{
if ( Gia_ObjIsTravIdCurrent(p, pObj) )
return pObj->fMark0;
Gia_ObjSetTravIdCurrent(p, pObj);
assert( pObj->fMark0 == 0 );
if ( Gia_ObjIsPi(p, pObj) || Gia_ObjIsConst0(pObj) )
return pObj->fMark0 = 1;
if ( Gia_ObjIsCo(pObj) )
return pObj->fMark0 = Gia_ManMarkAutonomous_rec( p, Gia_ObjFanin0(pObj) );
if ( Gia_ObjIsCi(pObj) )
return pObj->fMark0 = Gia_ManMarkAutonomous_rec( p, Gia_ObjRoToRi(p, pObj) );
assert( Gia_ObjIsAnd(pObj) );
if ( Gia_ManMarkAutonomous_rec( p, Gia_ObjFanin0(pObj) ) )
return pObj->fMark0 = 1;
return pObj->fMark0 = Gia_ManMarkAutonomous_rec( p, Gia_ObjFanin1(pObj) );
}
/**Function*************************************************************
Synopsis [Marks with current trav ROs reachable from Const0 and PIs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Gia_ManMarkAutonomous( Gia_Man_t * p )
{
Gia_Obj_t * pObj;
int i;
Gia_ManCleanMark0( p );
Gia_ManIncrementTravId( p );
Gia_ManForEachRo( p, pObj, i )
Gia_ManMarkAutonomous_rec( p, pObj );
Gia_ManIncrementTravId( p );
Gia_ManForEachRo( p, pObj, i )
if ( pObj->fMark0 )
Gia_ObjSetTravIdCurrent( p, pObj );
Gia_ManCleanMark0( p );
}
/**Function*************************************************************
Synopsis [Duplicates the AIG recursively.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Gia_ManRetimeDup_rec( Gia_Man_t * pNew, Gia_Obj_t * pObj )
{
if ( ~pObj->Value )
return;
assert( Gia_ObjIsAnd(pObj) );
Gia_ManRetimeDup_rec( pNew, Gia_ObjFanin0(pObj) );
Gia_ManRetimeDup_rec( pNew, Gia_ObjFanin1(pObj) );
pObj->Value = Gia_ManHashAnd( pNew, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
}
/**Function*************************************************************
Synopsis [Duplicates the AIG while retiming the registers to the cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Gia_Man_t * Gia_ManRetimeDupForward( Gia_Man_t * p, Vec_Ptr_t * vCut )
{
Gia_Man_t * pNew, * pTemp;
Gia_Obj_t * pObj, * pObjRi, * pObjRo;
int i;
// create the new manager
pNew = Gia_ManStart( Gia_ManObjNum(p) );
pNew->pName = Abc_UtilStrsav( p->pName );
Gia_ManHashAlloc( pNew );
// create the true PIs
Gia_ManFillValue( p );
Gia_ManSetPhase( p );
Gia_ManConst0(p)->Value = 0;
Gia_ManForEachPi( p, pObj, i )
pObj->Value = Gia_ManAppendCi( pNew );
// create the registers
Vec_PtrForEachEntry( Gia_Obj_t *, vCut, pObj, i )
pObj->Value = Abc_LitNotCond( Gia_ManAppendCi(pNew), pObj->fPhase );
// duplicate logic above the cut
Gia_ManForEachCo( p, pObj, i )
Gia_ManRetimeDup_rec( pNew, Gia_ObjFanin0(pObj) );
// create the true POs
Gia_ManForEachPo( p, pObj, i )
Gia_ManAppendCo( pNew, Gia_ObjFanin0Copy(pObj) );
// remember value in LI
Gia_ManForEachRi( p, pObj, i )
pObj->Value = Gia_ObjFanin0Copy(pObj);
// transfer values from the LIs to the LOs
Gia_ManForEachRiRo( p, pObjRi, pObjRo, i )
pObjRo->Value = pObjRi->Value;
// erase the data values on the internal nodes of the cut
Vec_PtrForEachEntry( Gia_Obj_t *, vCut, pObj, i )
if ( Gia_ObjIsAnd(pObj) )
pObj->Value = ~0;
// duplicate logic below the cut
Vec_PtrForEachEntry( Gia_Obj_t *, vCut, pObj, i )
{
Gia_ManRetimeDup_rec( pNew, pObj );
Gia_ManAppendCo( pNew, Abc_LitNotCond( pObj->Value, pObj->fPhase ) );
}
Gia_ManHashStop( pNew );
Gia_ManSetRegNum( pNew, Vec_PtrSize(vCut) );
pNew = Gia_ManCleanup( pTemp = pNew );
Gia_ManStop( pTemp );
return pNew;
}
/**Function*************************************************************
Synopsis [Derives the cut for forward retiming.]
Description [Assumes topological ordering of the nodes.]
SideEffects []
SeeAlso []
***********************************************************************/
Gia_Man_t * Gia_ManRetimeForwardOne( Gia_Man_t * p, int * pnRegFixed, int * pnRegMoves )
{
Vec_Int_t * vFlopClasses = NULL;
Vec_Int_t * vObjClasses = NULL;
Gia_Man_t * pNew;
Vec_Ptr_t * vCut;
Gia_Obj_t * pObj;
int i;
if ( p->vFlopClasses )
{
// printf( "Performing retiming with register classes.\n" );
vObjClasses = Vec_IntAlloc( Gia_ManObjNum(p) );
for ( i = 0; i < Gia_ManObjNum(p); i++ )
Vec_IntPush( vObjClasses, -1 );
Gia_ManForEachRo( p, pObj, i )
Vec_IntWriteEntry( vObjClasses, Gia_ObjId(p, pObj), Vec_IntEntry(p->vFlopClasses, i) );
vFlopClasses = Vec_IntAlloc( Gia_ManRegNum(p) );
}
// mark the retimable nodes
Gia_ManIncrementTravId( p );
Gia_ManMarkAutonomous( p );
// mark the retimable registers with the fresh trav ID
Gia_ManIncrementTravId( p );
*pnRegFixed = 0;
Gia_ManForEachRo( p, pObj, i )
if ( Gia_ObjIsTravIdPrevious(p, pObj) )
Gia_ObjSetTravIdCurrent(p, pObj);
else
(*pnRegFixed)++;
// mark all the nodes that can be retimed forward
*pnRegMoves = 0;
Gia_ManForEachAnd( p, pObj, i )
if ( Gia_ObjIsTravIdCurrent(p, Gia_ObjFanin0(pObj)) && Gia_ObjIsTravIdCurrent(p, Gia_ObjFanin1(pObj)) )
{
if ( vObjClasses && Vec_IntEntry(vObjClasses, Gia_ObjFaninId0(pObj, i)) != Vec_IntEntry(vObjClasses, Gia_ObjFaninId1(pObj, i)) )
continue;
if ( vObjClasses )
Vec_IntWriteEntry( vObjClasses, Gia_ObjId(p, pObj), Vec_IntEntry(vObjClasses, Gia_ObjFaninId0(pObj, i)) );
Gia_ObjSetTravIdCurrent(p, pObj);
(*pnRegMoves)++;
}
// mark the remaining registers
Gia_ManForEachRo( p, pObj, i )
Gia_ObjSetTravIdCurrent(p, pObj);
// find the cut (all such marked objects that fanout into unmarked nodes)
vCut = Vec_PtrAlloc( 1000 );
Gia_ManIncrementTravId( p );
Gia_ManForEachObj( p, pObj, i )
{
if ( Gia_ObjIsTravIdPrevious(p, pObj) )
continue;
if ( (Gia_ObjIsCo(pObj) || Gia_ObjIsAnd(pObj)) && Gia_ObjIsTravIdPrevious(p, Gia_ObjFanin0(pObj)) )
{
if ( vFlopClasses )
Vec_IntPush( vFlopClasses, Vec_IntEntry(vObjClasses, Gia_ObjFaninId0(pObj, i)) );
Vec_PtrPush( vCut, Gia_ObjFanin0(pObj) );
Gia_ObjSetTravIdCurrent( p, Gia_ObjFanin0(pObj) );
}
if ( Gia_ObjIsAnd(pObj) && Gia_ObjIsTravIdPrevious(p, Gia_ObjFanin1(pObj)) )
{
if ( vFlopClasses )
Vec_IntPush( vFlopClasses, Vec_IntEntry(vObjClasses, Gia_ObjFaninId1(pObj, i)) );
Vec_PtrPush( vCut, Gia_ObjFanin1(pObj) );
Gia_ObjSetTravIdCurrent( p, Gia_ObjFanin1(pObj) );
}
}
assert( vFlopClasses == NULL || Vec_IntSize(vFlopClasses) == Vec_PtrSize(vCut) );
// finally derive the new manager
pNew = Gia_ManRetimeDupForward( p, vCut );
Vec_PtrFree( vCut );
if ( vObjClasses )
Vec_IntFree( vObjClasses );
pNew->vFlopClasses = vFlopClasses;
return pNew;
}
/**Function*************************************************************
Synopsis [Derives the cut for forward retiming.]
Description [Assumes topological ordering of the nodes.]
SideEffects []
SeeAlso []
***********************************************************************/
Gia_Man_t * Gia_ManRetimeForward( Gia_Man_t * p, int nMaxIters, int fVerbose )
{
Gia_Man_t * pNew, * pTemp;
int i, nRegFixed, nRegMoves = 1;
clock_t clk;
pNew = p;
for ( i = 0; i < nMaxIters && nRegMoves > 0; i++ )
{
clk = clock();
pNew = Gia_ManRetimeForwardOne( pTemp = pNew, &nRegFixed, &nRegMoves );
if ( fVerbose )
{
printf( "%2d : And = %6d. Reg = %5d. Unret = %5d. Move = %6d. ",
i + 1, Gia_ManAndNum(pTemp), Gia_ManRegNum(pTemp), nRegFixed, nRegMoves );
ABC_PRT( "Time", clock() - clk );
}
if ( pTemp != p )
Gia_ManStop( pTemp );
}
/*
clk = clock();
pNew = Gia_ManReduceLaches( pNew, fVerbose );
if ( fVerbose )
{
ABC_PRT( "Register sharing time", clock() - clk );
}
*/
return pNew;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
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