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/**CFile****************************************************************
FileName [saigRetStep.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Sequential AIG package.]
Synopsis [Implementation of retiming steps.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: saigRetStep.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "saig.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs one retiming step forward.]
Description [Returns the pointer to the register output after retiming.]
SideEffects [Remember to run Aig_ManSetPioNumbers() in advance.]
SeeAlso []
***********************************************************************/
Aig_Obj_t * Saig_ManRetimeNodeFwd( Aig_Man_t * p, Aig_Obj_t * pObj, int fMakeBug )
{
Aig_Obj_t * pFanin0, * pFanin1;
Aig_Obj_t * pInput0, * pInput1;
Aig_Obj_t * pObjNew, * pObjLi, * pObjLo;
int fCompl;
assert( Saig_ManRegNum(p) > 0 );
assert( Aig_ObjIsNode(pObj) );
// get the fanins
pFanin0 = Aig_ObjFanin0(pObj);
pFanin1 = Aig_ObjFanin1(pObj);
// skip of they are not primary inputs
if ( !Aig_ObjIsCi(pFanin0) || !Aig_ObjIsCi(pFanin1) )
return NULL;
// skip of they are not register outputs
if ( !Saig_ObjIsLo(p, pFanin0) || !Saig_ObjIsLo(p, pFanin1) )
return NULL;
assert( Aig_ObjPioNum(pFanin0) > 0 );
assert( Aig_ObjPioNum(pFanin1) > 0 );
// skip latch guns
if ( !Aig_ObjIsTravIdCurrent(p, pFanin0) && !Aig_ObjIsTravIdCurrent(p, pFanin1) )
return NULL;
// get the inputs of these registers
pInput0 = Saig_ManLi( p, Aig_ObjPioNum(pFanin0) - Saig_ManPiNum(p) );
pInput1 = Saig_ManLi( p, Aig_ObjPioNum(pFanin1) - Saig_ManPiNum(p) );
pInput0 = Aig_ObjChild0( pInput0 );
pInput1 = Aig_ObjChild0( pInput1 );
pInput0 = Aig_NotCond( pInput0, Aig_ObjFaninC0(pObj) );
pInput1 = Aig_NotCond( pInput1, Aig_ObjFaninC1(pObj) );
// get the condition when the register should be complemetned
fCompl = Aig_ObjFaninC0(pObj) && Aig_ObjFaninC1(pObj);
if ( fMakeBug )
{
printf( "Introducing bug during retiming.\n" );
pInput1 = Aig_Not( pInput1 );
}
// create new node
pObjNew = Aig_And( p, pInput0, pInput1 );
// create new register input
pObjLi = Aig_ObjCreateCo( p, Aig_NotCond(pObjNew, fCompl) );
pObjLi->PioNum = Aig_ManCoNum(p) - 1;
// create new register output
pObjLo = Aig_ObjCreateCi( p );
pObjLo->PioNum = Aig_ManCiNum(p) - 1;
p->nRegs++;
// make sure the register is retimable.
Aig_ObjSetTravIdCurrent(p, pObjLo);
//printf( "Reg = %4d. Reg = %4d. Compl = %d. Phase = %d.\n",
// pFanin0->PioNum, pFanin1->PioNum, Aig_IsComplement(pObjNew), fCompl );
// return register output
return Aig_NotCond( pObjLo, fCompl );
}
/**Function*************************************************************
Synopsis [Performs one retiming step backward.]
Description [Returns the pointer to node after retiming.]
SideEffects [Remember to run Aig_ManSetPioNumbers() in advance.]
SeeAlso []
***********************************************************************/
Aig_Obj_t * Saig_ManRetimeNodeBwd( Aig_Man_t * p, Aig_Obj_t * pObjLo )
{
Aig_Obj_t * pFanin0, * pFanin1;
Aig_Obj_t * pLo0New, * pLo1New;
Aig_Obj_t * pLi0New, * pLi1New;
Aig_Obj_t * pObj, * pObjNew, * pObjLi;
int fCompl0, fCompl1;
assert( Saig_ManRegNum(p) > 0 );
assert( Aig_ObjPioNum(pObjLo) > 0 );
assert( Saig_ObjIsLo(p, pObjLo) );
// get the corresponding latch input
pObjLi = Saig_ManLi( p, Aig_ObjPioNum(pObjLo) - Saig_ManPiNum(p) );
// get the node
pObj = Aig_ObjFanin0(pObjLi);
if ( !Aig_ObjIsNode(pObj) )
return NULL;
// get the fanins
pFanin0 = Aig_ObjFanin0(pObj);
pFanin1 = Aig_ObjFanin1(pObj);
// get the complemented attributes of the fanins
fCompl0 = Aig_ObjFaninC0(pObj) ^ Aig_ObjFaninC0(pObjLi);
fCompl1 = Aig_ObjFaninC1(pObj) ^ Aig_ObjFaninC0(pObjLi);
// create latch inputs
pLi0New = Aig_ObjCreateCo( p, Aig_NotCond(pFanin0, fCompl0) );
pLi0New->PioNum = Aig_ManCoNum(p) - 1;
pLi1New = Aig_ObjCreateCo( p, Aig_NotCond(pFanin1, fCompl1) );
pLi1New->PioNum = Aig_ManCoNum(p) - 1;
// create latch outputs
pLo0New = Aig_ObjCreateCi(p);
pLo0New->PioNum = Aig_ManCiNum(p) - 1;
pLo1New = Aig_ObjCreateCi(p);
pLo1New->PioNum = Aig_ManCiNum(p) - 1;
pLo0New = Aig_NotCond( pLo0New, fCompl0 );
pLo1New = Aig_NotCond( pLo1New, fCompl1 );
p->nRegs += 2;
// create node
pObjNew = Aig_And( p, pLo0New, pLo1New );
// assert( pObjNew->fPhase == 0 );
return pObjNew;
}
/**Function*************************************************************
Synopsis [Performs the given number of retiming steps.]
Description [Returns the pointer to node after retiming.]
SideEffects [Remember to run Aig_ManSetPioNumbers() in advance.]
SeeAlso []
***********************************************************************/
int Saig_ManRetimeSteps( Aig_Man_t * p, int nSteps, int fForward, int fAddBugs )
{
Aig_Obj_t * pObj, * pObjNew;
int RetValue, s, i;
Aig_ManSetPioNumbers( p );
Aig_ManFanoutStart( p );
p->fCreatePios = 1;
if ( fForward )
{
Saig_ManMarkAutonomous( p );
for ( s = 0; s < nSteps; s++ )
{
Aig_ManForEachNode( p, pObj, i )
{
pObjNew = Saig_ManRetimeNodeFwd( p, pObj, fAddBugs && (s == 10) );
// pObjNew = Saig_ManRetimeNodeFwd( p, pObj, 0 );
if ( pObjNew == NULL )
continue;
Aig_ObjReplace( p, pObj, pObjNew, 0 );
break;
}
if ( i == Vec_PtrSize(p->vObjs) )
break;
}
}
else
{
for ( s = 0; s < nSteps; s++ )
{
Saig_ManForEachLo( p, pObj, i )
{
pObjNew = Saig_ManRetimeNodeBwd( p, pObj );
if ( pObjNew == NULL )
continue;
Aig_ObjReplace( p, pObj, pObjNew, 0 );
break;
}
if ( i == Vec_PtrSize(p->vObjs) )
break;
}
}
p->fCreatePios = 0;
Aig_ManFanoutStop( p );
RetValue = Aig_ManCleanup( p );
assert( RetValue == 0 );
Aig_ManSetRegNum( p, p->nRegs );
return s;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
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