/**CFile****************************************************************
FileName [retInit.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Retiming package.]
Synopsis [Initial state computation for backward retiming.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - Oct 31, 2006.]
Revision [$Id: retInit.c,v 1.00 2006/10/31 00:00:00 alanmi Exp $]
***********************************************************************/
#include "retInt.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static int Abc_NtkRetimeVerifyModel( Abc_Ntk_t * pNtkCone, Vec_Int_t * vValues, int * pModel );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Computes initial values of the new latches.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Abc_NtkRetimeInitialValues( Abc_Ntk_t * pNtkCone, Vec_Int_t * vValues, int fVerbose )
{
Vec_Int_t * vSolution;
Abc_Ntk_t * pNtkMiter, * pNtkLogic;
int RetValue, clk;
if ( pNtkCone == NULL )
return Vec_IntDup( vValues );
// convert the target network to AIG
pNtkLogic = Abc_NtkDup( pNtkCone );
Abc_NtkToAig( pNtkLogic );
// get the miter
pNtkMiter = Abc_NtkCreateTarget( pNtkLogic, pNtkLogic->vCos, vValues );
if ( fVerbose )
printf( "The miter for initial state computation has %d AIG nodes. ", Abc_NtkNodeNum(pNtkMiter) );
// solve the miter
clk = clock();
RetValue = Abc_NtkMiterSat( pNtkMiter, (ABC_INT64_T)500000, (ABC_INT64_T)50000000, 0, NULL, NULL );
if ( fVerbose )
{ ABC_PRT( "SAT solving time", clock() - clk ); }
// analyze the result
if ( RetValue == 1 )
printf( "Abc_NtkRetimeInitialValues(): The problem is unsatisfiable. DC latch values are used.\n" );
else if ( RetValue == -1 )
printf( "Abc_NtkRetimeInitialValues(): The SAT problem timed out. DC latch values are used.\n" );
else if ( !Abc_NtkRetimeVerifyModel( pNtkCone, vValues, pNtkMiter->pModel ) )
printf( "Abc_NtkRetimeInitialValues(): The computed counter-example is incorrect.\n" );
// set the values of the latches
vSolution = RetValue? NULL : Vec_IntAllocArray( pNtkMiter->pModel, Abc_NtkPiNum(pNtkLogic) );
pNtkMiter->pModel = NULL;
Abc_NtkDelete( pNtkMiter );
Abc_NtkDelete( pNtkLogic );
return vSolution;
}
/**Function*************************************************************
Synopsis [Computes the results of simulating one node.]
Description [Assumes that fanins have pCopy set to the input values.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_ObjSopSimulate( Abc_Obj_t * pObj )
{
char * pCube, * pSop = (char *)pObj->pData;
int nVars, Value, v, ResOr, ResAnd, ResVar;
assert( pSop && !Abc_SopIsExorType(pSop) );
// simulate the SOP of the node
ResOr = 0;
nVars = Abc_SopGetVarNum(pSop);
Abc_SopForEachCube( pSop, nVars, pCube )
{
ResAnd = 1;
Abc_CubeForEachVar( pCube, Value, v )
{
if ( Value == '0' )
ResVar = 1 ^ ((int)(ABC_PTRUINT_T)Abc_ObjFanin(pObj, v)->pCopy);
else if ( Value == '1' )
ResVar = (int)(ABC_PTRUINT_T)Abc_ObjFanin(pObj, v)->pCopy;
else
continue;
ResAnd &= ResVar;
}
ResOr |= ResAnd;
}
// complement the result if necessary
if ( !Abc_SopGetPhase(pSop) )
ResOr ^= 1;
return ResOr;
}
/**Function*************************************************************
Synopsis [Verifies the counter-example.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NtkRetimeVerifyModel( Abc_Ntk_t * pNtkCone, Vec_Int_t * vValues, int * pModel )
{
Vec_Ptr_t * vNodes;
Abc_Obj_t * pObj;
int i, Counter = 0;
assert( Abc_NtkIsSopLogic(pNtkCone) );
// set the PIs
Abc_NtkForEachPi( pNtkCone, pObj, i )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)pModel[i];
// simulate the internal nodes
vNodes = Abc_NtkDfs( pNtkCone, 0 );
Vec_PtrForEachEntry( Abc_Obj_t *, vNodes, pObj, i )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)Abc_ObjSopSimulate( pObj );
Vec_PtrFree( vNodes );
// compare the outputs
Abc_NtkForEachPo( pNtkCone, pObj, i )
pObj->pCopy = Abc_ObjFanin0(pObj)->pCopy;
Abc_NtkForEachPo( pNtkCone, pObj, i )
Counter += (Vec_IntEntry(vValues, i) != (int)(ABC_PTRUINT_T)pObj->pCopy);
if ( Counter > 0 )
printf( "%d outputs (out of %d) have a value mismatch.\n", Counter, Abc_NtkPoNum(pNtkCone) );
return 1;
}
/**Function*************************************************************
Synopsis [Transfer latch initial values to pCopy.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkRetimeTranferToCopy( Abc_Ntk_t * pNtk )
{
Abc_Obj_t * pObj;
int i;
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)Abc_LatchIsInit1(pObj);
}
/**Function*************************************************************
Synopsis [Transfer latch initial values from pCopy.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkRetimeTranferFromCopy( Abc_Ntk_t * pNtk )
{
Abc_Obj_t * pObj;
int i;
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
pObj->pData = (void *)(ABC_PTRUINT_T)(pObj->pCopy? ABC_INIT_ONE : ABC_INIT_ZERO);
}
/**Function*************************************************************
Synopsis [Transfer latch initial values to pCopy.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Abc_NtkRetimeCollectLatchValues( Abc_Ntk_t * pNtk )
{
Vec_Int_t * vValues;
Abc_Obj_t * pObj;
int i;
vValues = Vec_IntAlloc( Abc_NtkLatchNum(pNtk) );
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
Vec_IntPush( vValues, Abc_LatchIsInit1(pObj) );
return vValues;
}
/**Function*************************************************************
Synopsis [Transfer latch initial values from pCopy.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkRetimeInsertLatchValues( Abc_Ntk_t * pNtk, Vec_Int_t * vValues )
{
Abc_Obj_t * pObj;
int i, Counter = 0;
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)Counter++;
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
pObj->pData = (Abc_Obj_t *)(ABC_PTRUINT_T)(vValues? (Vec_IntEntry(vValues,(int)(ABC_PTRUINT_T)pObj->pCopy)? ABC_INIT_ONE : ABC_INIT_ZERO) : ABC_INIT_DC);
}
/**Function*************************************************************
Synopsis [Transfer latch initial values to pCopy.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Ntk_t * Abc_NtkRetimeBackwardInitialStart( Abc_Ntk_t * pNtk )
{
Abc_Ntk_t * pNtkNew;
Abc_Obj_t * pObj;
int i;
// create the network used for the initial state computation
pNtkNew = Abc_NtkAlloc( ABC_NTK_LOGIC, ABC_FUNC_SOP, 1 );
// create POs corresponding to the initial values
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
pObj->pCopy = Abc_NtkCreatePo(pNtkNew);
return pNtkNew;
}
/**Function*************************************************************
Synopsis [Transfer latch initial values to pCopy.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkRetimeBackwardInitialFinish( Abc_Ntk_t * pNtk, Abc_Ntk_t * pNtkNew, Vec_Int_t * vValuesOld, int fVerbose )
{
Vec_Int_t * vValuesNew;
Abc_Obj_t * pObj;
int i;
// create PIs corresponding to the initial values
Abc_NtkForEachObj( pNtk, pObj, i )
if ( Abc_ObjIsLatch(pObj) )
Abc_ObjAddFanin( pObj->pCopy, Abc_NtkCreatePi(pNtkNew) );
// assign dummy node names
Abc_NtkAddDummyPiNames( pNtkNew );
Abc_NtkAddDummyPoNames( pNtkNew );
// check the network
if ( !Abc_NtkCheck( pNtkNew ) )
fprintf( stdout, "Abc_NtkRetimeBackwardInitialFinish(): Network check has failed.\n" );
// derive new initial values
vValuesNew = Abc_NtkRetimeInitialValues( pNtkNew, vValuesOld, fVerbose );
// insert new initial values
Abc_NtkRetimeInsertLatchValues( pNtk, vValuesNew );
if ( vValuesNew ) Vec_IntFree( vValuesNew );
}
/**Function*************************************************************
Synopsis [Cycles the circuit to create a new initial state.]
Description [Simulates the circuit with random input for the given
number of timeframes to get a better initial state.]
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkCycleInitStateSop( Abc_Ntk_t * pNtk, int nFrames, int fVerbose )
{
Vec_Ptr_t * vNodes;
Abc_Obj_t * pObj;
int i, f;
assert( Abc_NtkIsSopLogic(pNtk) );
srand( 0x12341234 );
// initialize the values
Abc_NtkForEachPi( pNtk, pObj, i )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)(rand() & 1);
Abc_NtkForEachLatch( pNtk, pObj, i )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)Abc_LatchIsInit1(pObj);
// simulate for the given number of timeframes
vNodes = Abc_NtkDfs( pNtk, 0 );
for ( f = 0; f < nFrames; f++ )
{
// simulate internal nodes
Vec_PtrForEachEntry( Abc_Obj_t *, vNodes, pObj, i )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)Abc_ObjSopSimulate( pObj );
// bring the results to the COs
Abc_NtkForEachCo( pNtk, pObj, i )
pObj->pCopy = Abc_ObjFanin0(pObj)->pCopy;
// assign PI values
Abc_NtkForEachPi( pNtk, pObj, i )
pObj->pCopy = (Abc_Obj_t *)(ABC_PTRUINT_T)(rand() & 1);
// transfer the latch values
Abc_NtkForEachLatch( pNtk, pObj, i )
Abc_ObjFanout0(pObj)->pCopy = Abc_ObjFanin0(pObj)->pCopy;
}
Vec_PtrFree( vNodes );
// set the final values
Abc_NtkForEachLatch( pNtk, pObj, i )
pObj->pData = (void *)(ABC_PTRUINT_T)(Abc_ObjFanout0(pObj)->pCopy ? ABC_INIT_ONE : ABC_INIT_ZERO);
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END