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abc/src/base/seq/seqAigCore.c

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Version abc51126
2005-11-26 17:01:00 +01:00
/**CFile****************************************************************
FileName [seqRetCore.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Construction and manipulation of sequential AIGs.]
Synopsis [The core of retiming procedures.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: seqRetCore.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "seqInt.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
/*
Retiming can be represented in three equivalent forms:
- as a set of integer lags for each node (array of chars by node ID)
- as a set of node numbers with lag for each, fwd and bwd (two arrays of Seq_RetStep_t_)
- as a set of latch moves over the nodes, fwd and bwd (two arrays of node pointers Abc_Obj_t *)
*/
static void Abc_ObjRetimeForward( Abc_Obj_t * pObj );
static int Abc_ObjRetimeBackward( Abc_Obj_t * pObj, Abc_Ntk_t * pNtk, stmm_table * tTable, Vec_Int_t * vValues );
static void Abc_ObjRetimeBackwardUpdateEdge( Abc_Obj_t * pObj, int Edge, stmm_table * tTable );
static void Abc_NtkRetimeSetInitialValues( Abc_Ntk_t * pNtk, stmm_table * tTable, int * pModel );
static void Seq_NtkImplementRetimingForward( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMoves );
static int Seq_NtkImplementRetimingBackward( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMoves, int fVerbose );
static void Abc_ObjRetimeForward( Abc_Obj_t * pObj );
static int Abc_ObjRetimeBackward( Abc_Obj_t * pObj, Abc_Ntk_t * pNtk, stmm_table * tTable, Vec_Int_t * vValues );
static void Abc_ObjRetimeBackwardUpdateEdge( Abc_Obj_t * pObj, int Edge, stmm_table * tTable );
static void Abc_NtkRetimeSetInitialValues( Abc_Ntk_t * pNtk, stmm_table * tTable, int * pModel );
static Vec_Ptr_t * Abc_NtkUtilRetimingTry( Abc_Ntk_t * pNtk, bool fForward );
static Vec_Ptr_t * Abc_NtkUtilRetimingGetMoves( Abc_Ntk_t * pNtk, Vec_Int_t * vSteps, bool fForward );
static Vec_Int_t * Abc_NtkUtilRetimingSplit( Vec_Str_t * vLags, int fForward );
static void Abc_ObjRetimeForwardTry( Abc_Obj_t * pObj, int nLatches );
static void Abc_ObjRetimeBackwardTry( Abc_Obj_t * pObj, int nLatches );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Performs performs optimal delay retiming.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
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void Seq_NtkSeqRetimeDelay( Abc_Ntk_t * pNtk, int nMaxIters, int fInitial, int fVerbose )
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{
Abc_Seq_t * p = pNtk->pManFunc;
int RetValue;
if ( !fInitial )
Seq_NtkLatchSetValues( pNtk, ABC_INIT_DC );
// get the retiming lags
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p->nMaxIters = nMaxIters;
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Seq_AigRetimeDelayLags( pNtk, fVerbose );
// implement this retiming
RetValue = Seq_NtkImplementRetiming( pNtk, p->vLags, fVerbose );
if ( RetValue == 0 )
printf( "Retiming completed but initial state computation has failed.\n" );
}
/**Function*************************************************************
Synopsis [Performs most forward retiming.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Seq_NtkSeqRetimeForward( Abc_Ntk_t * pNtk, int fInitial, int fVerbose )
{
Vec_Ptr_t * vMoves;
Abc_Obj_t * pNode;
int i;
if ( !fInitial )
Seq_NtkLatchSetValues( pNtk, ABC_INIT_DC );
// get the forward moves
vMoves = Abc_NtkUtilRetimingTry( pNtk, 1 );
// undo the forward moves
Vec_PtrForEachEntryReverse( vMoves, pNode, i )
Abc_ObjRetimeBackwardTry( pNode, 1 );
// implement this forward retiming
Seq_NtkImplementRetimingForward( pNtk, vMoves );
Vec_PtrFree( vMoves );
}
/**Function*************************************************************
Synopsis [Performs most backward retiming.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Seq_NtkSeqRetimeBackward( Abc_Ntk_t * pNtk, int fInitial, int fVerbose )
{
Vec_Ptr_t * vMoves;
Abc_Obj_t * pNode;
int i, RetValue;
if ( !fInitial )
Seq_NtkLatchSetValues( pNtk, ABC_INIT_DC );
// get the backward moves
vMoves = Abc_NtkUtilRetimingTry( pNtk, 0 );
// undo the backward moves
Vec_PtrForEachEntryReverse( vMoves, pNode, i )
Abc_ObjRetimeForwardTry( pNode, 1 );
// implement this backward retiming
RetValue = Seq_NtkImplementRetimingBackward( pNtk, vMoves, fVerbose );
Vec_PtrFree( vMoves );
if ( RetValue == 0 )
printf( "Retiming completed but initial state computation has failed.\n" );
}
/**Function*************************************************************
Synopsis [Implements the retiming on the sequential AIG.]
Description [Split the retiming into forward and backward.]
SideEffects []
SeeAlso []
***********************************************************************/
int Seq_NtkImplementRetiming( Abc_Ntk_t * pNtk, Vec_Str_t * vLags, int fVerbose )
{
Vec_Int_t * vSteps;
Vec_Ptr_t * vMoves;
int RetValue;
// forward retiming
vSteps = Abc_NtkUtilRetimingSplit( vLags, 1 );
// translate each set of steps into moves
if ( fVerbose )
printf( "The number of forward steps = %6d.\n", Vec_IntSize(vSteps) );
vMoves = Abc_NtkUtilRetimingGetMoves( pNtk, vSteps, 1 );
if ( fVerbose )
printf( "The number of forward moves = %6d.\n", Vec_PtrSize(vMoves) );
// implement this retiming
Seq_NtkImplementRetimingForward( pNtk, vMoves );
Vec_IntFree( vSteps );
Vec_PtrFree( vMoves );
// backward retiming
vSteps = Abc_NtkUtilRetimingSplit( vLags, 0 );
// translate each set of steps into moves
if ( fVerbose )
printf( "The number of backward steps = %6d.\n", Vec_IntSize(vSteps) );
vMoves = Abc_NtkUtilRetimingGetMoves( pNtk, vSteps, 0 );
if ( fVerbose )
printf( "The number of backward moves = %6d.\n", Vec_PtrSize(vMoves) );
// implement this retiming
RetValue = Seq_NtkImplementRetimingBackward( pNtk, vMoves, fVerbose );
Vec_IntFree( vSteps );
Vec_PtrFree( vMoves );
return RetValue;
}
/**Function*************************************************************
Synopsis [Implements the given retiming on the sequential AIG.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Seq_NtkImplementRetimingForward( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMoves )
{
Abc_Obj_t * pNode;
int i;
Vec_PtrForEachEntry( vMoves, pNode, i )
Abc_ObjRetimeForward( pNode );
}
/**Function*************************************************************
Synopsis [Retimes node forward by one latch.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_ObjRetimeForward( Abc_Obj_t * pObj )
{
Abc_Obj_t * pFanout;
int Init0, Init1, Init, i;
assert( Abc_ObjFaninNum(pObj) == 2 );
assert( Seq_ObjFaninL0(pObj) >= 1 );
assert( Seq_ObjFaninL1(pObj) >= 1 );
// remove the init values from the fanins
Init0 = Seq_NodeDeleteFirst( pObj, 0 );
Init1 = Seq_NodeDeleteFirst( pObj, 1 );
assert( Init0 != ABC_INIT_NONE );
assert( Init1 != ABC_INIT_NONE );
// take into account the complements in the node
if ( Abc_ObjFaninC0(pObj) )
{
if ( Init0 == ABC_INIT_ZERO )
Init0 = ABC_INIT_ONE;
else if ( Init0 == ABC_INIT_ONE )
Init0 = ABC_INIT_ZERO;
}
if ( Abc_ObjFaninC1(pObj) )
{
if ( Init1 == ABC_INIT_ZERO )
Init1 = ABC_INIT_ONE;
else if ( Init1 == ABC_INIT_ONE )
Init1 = ABC_INIT_ZERO;
}
// compute the value at the output of the node
if ( Init0 == ABC_INIT_ZERO || Init1 == ABC_INIT_ZERO )
Init = ABC_INIT_ZERO;
else if ( Init0 == ABC_INIT_ONE && Init1 == ABC_INIT_ONE )
Init = ABC_INIT_ONE;
else
Init = ABC_INIT_DC;
// make sure the label is clean
Abc_ObjForEachFanout( pObj, pFanout, i )
assert( pFanout->fMarkC == 0 );
// add the init values to the fanouts
Abc_ObjForEachFanout( pObj, pFanout, i )
{
if ( pFanout->fMarkC )
continue;
pFanout->fMarkC = 1;
if ( Abc_ObjFaninId0(pFanout) != Abc_ObjFaninId1(pFanout) )
Seq_NodeInsertLast( pFanout, Abc_ObjFanoutEdgeNum(pObj, pFanout), Init );
else
{
assert( Abc_ObjFanin0(pFanout) == pObj );
Seq_NodeInsertLast( pFanout, 0, Init );
Seq_NodeInsertLast( pFanout, 1, Init );
}
}
// clean the label
Abc_ObjForEachFanout( pObj, pFanout, i )
pFanout->fMarkC = 0;
}
/**Function*************************************************************
Synopsis [Implements the given retiming on the sequential AIG.]
Description [Returns 0 of initial state computation fails.]
SideEffects []
SeeAlso []
***********************************************************************/
int Seq_NtkImplementRetimingBackward( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMoves, int fVerbose )
{
Seq_RetEdge_t RetEdge;
stmm_table * tTable;
stmm_generator * gen;
Vec_Int_t * vValues;
Abc_Ntk_t * pNtkProb, * pNtkMiter, * pNtkCnf;
Abc_Obj_t * pNode, * pNodeNew;
int * pModel, RetValue, i, clk;
// return if the retiming is trivial
if ( Vec_PtrSize(vMoves) == 0 )
return 1;
// create the network for the initial state computation
// start the table and the array of PO values
pNtkProb = Abc_NtkAlloc( ABC_NTK_LOGIC, ABC_FUNC_SOP );
tTable = stmm_init_table( stmm_numcmp, stmm_numhash );
vValues = Vec_IntAlloc( 100 );
// perform the backward moves and build the network for initial state computation
RetValue = 0;
Vec_PtrForEachEntry( vMoves, pNode, i )
RetValue |= Abc_ObjRetimeBackward( pNode, pNtkProb, tTable, vValues );
// add the PIs corresponding to the white spots
stmm_foreach_item( tTable, gen, (char **)&RetEdge, (char **)&pNodeNew )
Abc_ObjAddFanin( pNodeNew, Abc_NtkCreatePi(pNtkProb) );
// add the PI/PO names
Abc_NtkAddDummyPiNames( pNtkProb );
Abc_NtkAddDummyPoNames( pNtkProb );
// make sure everything is okay with the network structure
if ( !Abc_NtkDoCheck( pNtkProb ) )
{
printf( "Seq_NtkImplementRetimingBackward: The internal network check has failed.\n" );
Abc_NtkRetimeSetInitialValues( pNtk, tTable, NULL );
Abc_NtkDelete( pNtkProb );
stmm_free_table( tTable );
Vec_IntFree( vValues );
return 0;
}
// check if conflict is found
if ( RetValue )
{
printf( "Seq_NtkImplementRetimingBackward: A top level conflict is detected. DC latch values are used.\n" );
Abc_NtkRetimeSetInitialValues( pNtk, tTable, NULL );
Abc_NtkDelete( pNtkProb );
stmm_free_table( tTable );
Vec_IntFree( vValues );
return 0;
}
// get the miter cone
pNtkMiter = Abc_NtkCreateCone( pNtkProb, pNtkProb->vCos, vValues );
Abc_NtkDelete( pNtkProb );
Vec_IntFree( vValues );
if ( fVerbose )
printf( "The number of ANDs in the AIG = %5d.\n", Abc_NtkNodeNum(pNtkMiter) );
// transform the miter into a logic network for efficient CNF construction
pNtkCnf = Abc_NtkRenode( pNtkMiter, 0, 100, 1, 0, 0 );
Abc_NtkDelete( pNtkMiter );
// solve the miter
clk = clock();
RetValue = Abc_NtkMiterSat( pNtkCnf, 30, 0 );
if ( fVerbose )
if ( clock() - clk > 100 )
{
PRT( "SAT solving time", clock() - clk );
}
pModel = pNtkCnf->pModel; pNtkCnf->pModel = NULL;
Abc_NtkDelete( pNtkCnf );
// analyze the result
if ( RetValue == -1 || RetValue == 1 )
{
Abc_NtkRetimeSetInitialValues( pNtk, tTable, NULL );
if ( RetValue == 1 )
printf( "Seq_NtkImplementRetimingBackward: The problem is unsatisfiable. DC latch values are used.\n" );
else
printf( "Seq_NtkImplementRetimingBackward: The SAT problem timed out. DC latch values are used.\n" );
stmm_free_table( tTable );
return 0;
}
// set the values of the latches
Abc_NtkRetimeSetInitialValues( pNtk, tTable, pModel );
stmm_free_table( tTable );
free( pModel );
return 1;
}
/**Function*************************************************************
Synopsis [Retimes node backward by one latch.]
Description [Constructs the problem for initial state computation.
Returns 1 if the conflict is found.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_ObjRetimeBackward( Abc_Obj_t * pObj, Abc_Ntk_t * pNtkNew, stmm_table * tTable, Vec_Int_t * vValues )
{
Abc_Obj_t * pFanout;
Abc_InitType_t Init, Value;
Seq_RetEdge_t RetEdge;
Abc_Obj_t * pNodeNew, * pFanoutNew, * pBuffer;
int i, Edge, fMet0, fMet1, fMetN;
// make sure the node can be retimed
assert( Seq_ObjFanoutLMin(pObj) > 0 );
// get the fanout values
fMet0 = fMet1 = fMetN = 0;
Abc_ObjForEachFanout( pObj, pFanout, i )
{
if ( Abc_ObjFaninId0(pFanout) == pObj->Id )
{
Init = Seq_NodeGetInitLast( pFanout, 0 );
if ( Init == ABC_INIT_ZERO )
fMet0 = 1;
else if ( Init == ABC_INIT_ONE )
fMet1 = 1;
else if ( Init == ABC_INIT_NONE )
fMetN = 1;
}
if ( Abc_ObjFaninId1(pFanout) == pObj->Id )
{
Init = Seq_NodeGetInitLast( pFanout, 1 );
if ( Init == ABC_INIT_ZERO )
fMet0 = 1;
else if ( Init == ABC_INIT_ONE )
fMet1 = 1;
else if ( Init == ABC_INIT_NONE )
fMetN = 1;
}
}
// consider the case when all fanout latches have don't-care values
// the new values on the fanin edges will be don't-cares
if ( !fMet0 && !fMet1 && !fMetN )
{
// make sure the label is clean
Abc_ObjForEachFanout( pObj, pFanout, i )
assert( pFanout->fMarkC == 0 );
// update the fanout edges
Abc_ObjForEachFanout( pObj, pFanout, i )
{
if ( pFanout->fMarkC )
continue;
pFanout->fMarkC = 1;
if ( Abc_ObjFaninId0(pFanout) == pObj->Id )
Seq_NodeDeleteLast( pFanout, 0 );
if ( Abc_ObjFaninId1(pFanout) == pObj->Id )
Seq_NodeDeleteLast( pFanout, 1 );
}
// clean the label
Abc_ObjForEachFanout( pObj, pFanout, i )
pFanout->fMarkC = 0;
// update the fanin edges
Abc_ObjRetimeBackwardUpdateEdge( pObj, 0, tTable );
Abc_ObjRetimeBackwardUpdateEdge( pObj, 1, tTable );
Seq_NodeInsertFirst( pObj, 0, ABC_INIT_DC );
Seq_NodeInsertFirst( pObj, 1, ABC_INIT_DC );
return 0;
}
// the initial values on the fanout edges contain 0, 1, or unknown
// the new values on the fanin edges will be unknown
// add new AND-gate to the network
pNodeNew = Abc_NtkCreateNode( pNtkNew );
pNodeNew->pData = Abc_SopCreateAnd2( pNtkNew->pManFunc, Abc_ObjFaninC0(pObj), Abc_ObjFaninC1(pObj) );
// add PO fanouts if any
if ( fMet0 )
{
Abc_ObjAddFanin( Abc_NtkCreatePo(pNtkNew), pNodeNew );
Vec_IntPush( vValues, 0 );
}
if ( fMet1 )
{
Abc_ObjAddFanin( Abc_NtkCreatePo(pNtkNew), pNodeNew );
Vec_IntPush( vValues, 1 );
}
// make sure the label is clean
Abc_ObjForEachFanout( pObj, pFanout, i )
assert( pFanout->fMarkC == 0 );
// perform the changes
Abc_ObjForEachFanout( pObj, pFanout, i )
{
if ( pFanout->fMarkC )
continue;
pFanout->fMarkC = 1;
if ( Abc_ObjFaninId0(pFanout) == pObj->Id )
{
Edge = 0;
Value = Seq_NodeDeleteLast( pFanout, Edge );
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if ( Value == ABC_INIT_NONE )
{
// value is unknown, remove it from the table
RetEdge.iNode = pFanout->Id;
RetEdge.iEdge = Edge;
RetEdge.iLatch = Seq_ObjFaninL( pFanout, Edge ); // after edge is removed
if ( !stmm_delete( tTable, (char **)&RetEdge, (char **)&pFanoutNew ) )
assert( 0 );
// create the fanout of the AND gate
Abc_ObjAddFanin( pFanoutNew, pNodeNew );
}
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}
if ( Abc_ObjFaninId1(pFanout) == pObj->Id )
{
Edge = 1;
Value = Seq_NodeDeleteLast( pFanout, Edge );
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if ( Value == ABC_INIT_NONE )
{
// value is unknown, remove it from the table
RetEdge.iNode = pFanout->Id;
RetEdge.iEdge = Edge;
RetEdge.iLatch = Seq_ObjFaninL( pFanout, Edge ); // after edge is removed
if ( !stmm_delete( tTable, (char **)&RetEdge, (char **)&pFanoutNew ) )
assert( 0 );
// create the fanout of the AND gate
Abc_ObjAddFanin( pFanoutNew, pNodeNew );
}
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}
}
// clean the label
Abc_ObjForEachFanout( pObj, pFanout, i )
pFanout->fMarkC = 0;
// update the fanin edges
Abc_ObjRetimeBackwardUpdateEdge( pObj, 0, tTable );
Abc_ObjRetimeBackwardUpdateEdge( pObj, 1, tTable );
Seq_NodeInsertFirst( pObj, 0, ABC_INIT_NONE );
Seq_NodeInsertFirst( pObj, 1, ABC_INIT_NONE );
// add the buffer
pBuffer = Abc_NtkCreateNode( pNtkNew );
pBuffer->pData = Abc_SopCreateBuf( pNtkNew->pManFunc );
Abc_ObjAddFanin( pNodeNew, pBuffer );
// point to it from the table
RetEdge.iNode = pObj->Id;
RetEdge.iEdge = 0;
RetEdge.iLatch = 0;
if ( stmm_insert( tTable, (char *)Seq_RetEdge2Int(RetEdge), (char *)pBuffer ) )
assert( 0 );
// add the buffer
pBuffer = Abc_NtkCreateNode( pNtkNew );
pBuffer->pData = Abc_SopCreateBuf( pNtkNew->pManFunc );
Abc_ObjAddFanin( pNodeNew, pBuffer );
// point to it from the table
RetEdge.iNode = pObj->Id;
RetEdge.iEdge = 1;
RetEdge.iLatch = 0;
if ( stmm_insert( tTable, (char *)Seq_RetEdge2Int(RetEdge), (char *)pBuffer ) )
assert( 0 );
// report conflict is found
return fMet0 && fMet1;
}
/**Function*************************************************************
Synopsis [Generates the printable edge label with the initial state.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_ObjRetimeBackwardUpdateEdge( Abc_Obj_t * pObj, int Edge, stmm_table * tTable )
{
Abc_Obj_t * pFanoutNew;
Seq_RetEdge_t RetEdge;
Abc_InitType_t Init;
int nLatches, i;
// get the number of latches on the edge
nLatches = Seq_ObjFaninL( pObj, Edge );
for ( i = nLatches - 1; i >= 0; i-- )
{
// get the value of this latch
Init = Seq_NodeGetInitOne( pObj, Edge, i );
if ( Init != ABC_INIT_NONE )
continue;
// get the retiming edge
RetEdge.iNode = pObj->Id;
RetEdge.iEdge = Edge;
RetEdge.iLatch = i;
// remove entry from table and add it with a different key
if ( !stmm_delete( tTable, (char **)&RetEdge, (char **)&pFanoutNew ) )
assert( 0 );
RetEdge.iLatch++;
if ( stmm_insert( tTable, (char *)Seq_RetEdge2Int(RetEdge), (char *)pFanoutNew ) )
assert( 0 );
}
}
/**Function*************************************************************
Synopsis [Sets the initial values.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkRetimeSetInitialValues( Abc_Ntk_t * pNtk, stmm_table * tTable, int * pModel )
{
Abc_Obj_t * pNode;
stmm_generator * gen;
Seq_RetEdge_t RetEdge;
Abc_InitType_t Init;
int i;
i = 0;
stmm_foreach_item( tTable, gen, (char **)&RetEdge, NULL )
{
pNode = Abc_NtkObj( pNtk, RetEdge.iNode );
Init = pModel? (pModel[i]? ABC_INIT_ONE : ABC_INIT_ZERO) : ABC_INIT_DC;
Seq_NodeSetInitOne( pNode, RetEdge.iEdge, RetEdge.iLatch, Init );
i++;
}
}
/**Function*************************************************************
Synopsis [Performs forward retiming of the sequential AIG.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_NtkUtilRetimingTry( Abc_Ntk_t * pNtk, bool fForward )
{
Vec_Ptr_t * vNodes, * vMoves;
Abc_Obj_t * pNode, * pFanout, * pFanin;
int i, k, nLatches;
assert( Abc_NtkIsSeq( pNtk ) );
// assume that all nodes can be retimed
vNodes = Vec_PtrAlloc( 100 );
Abc_AigForEachAnd( pNtk, pNode, i )
{
Vec_PtrPush( vNodes, pNode );
pNode->fMarkA = 1;
}
// process the nodes
vMoves = Vec_PtrAlloc( 100 );
Vec_PtrForEachEntry( vNodes, pNode, i )
{
// printf( "(%d,%d) ", Seq_ObjFaninL0(pNode), Seq_ObjFaninL0(pNode) );
// unmark the node as processed
pNode->fMarkA = 0;
// get the number of latches to retime
if ( fForward )
nLatches = Seq_ObjFaninLMin(pNode);
else
nLatches = Seq_ObjFanoutLMin(pNode);
if ( nLatches == 0 )
continue;
assert( nLatches > 0 );
// retime the latches forward
if ( fForward )
Abc_ObjRetimeForwardTry( pNode, nLatches );
else
Abc_ObjRetimeBackwardTry( pNode, nLatches );
// write the moves
for ( k = 0; k < nLatches; k++ )
Vec_PtrPush( vMoves, pNode );
// schedule fanouts for updating
if ( fForward )
{
Abc_ObjForEachFanout( pNode, pFanout, k )
{
if ( Abc_ObjFaninNum(pFanout) != 2 || pFanout->fMarkA )
continue;
pFanout->fMarkA = 1;
Vec_PtrPush( vNodes, pFanout );
}
}
else
{
Abc_ObjForEachFanin( pNode, pFanin, k )
{
if ( Abc_ObjFaninNum(pFanin) != 2 || pFanin->fMarkA )
continue;
pFanin->fMarkA = 1;
Vec_PtrPush( vNodes, pFanin );
}
}
}
Vec_PtrFree( vNodes );
// make sure the marks are clean the the retiming is final
Abc_AigForEachAnd( pNtk, pNode, i )
{
assert( pNode->fMarkA == 0 );
if ( fForward )
assert( Seq_ObjFaninLMin(pNode) == 0 );
else
assert( Seq_ObjFanoutLMin(pNode) == 0 );
}
return vMoves;
}
/**Function*************************************************************
Synopsis [Translates retiming steps into retiming moves.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_NtkUtilRetimingGetMoves( Abc_Ntk_t * pNtk, Vec_Int_t * vSteps, bool fForward )
{
Seq_RetStep_t RetStep;
Vec_Ptr_t * vMoves;
Abc_Obj_t * pNode;
int i, k, iNode, nLatches, Number;
int fChange;
assert( Abc_NtkIsSeq( pNtk ) );
/*
// try implementing all the moves at once
Vec_IntForEachEntry( vSteps, Number, i )
{
// get the retiming step
RetStep = Seq_Int2RetStep( Number );
// get the node to be retimed
pNode = Abc_NtkObj( pNtk, RetStep.iNode );
assert( RetStep.nLatches > 0 );
nLatches = RetStep.nLatches;
if ( fForward )
Abc_ObjRetimeForwardTry( pNode, nLatches );
else
Abc_ObjRetimeBackwardTry( pNode, nLatches );
}
// now look if any node has wrong number of latches
Abc_AigForEachAnd( pNtk, pNode, i )
{
if ( Seq_ObjFaninL0(pNode) < 0 )
printf( "Wrong 0node %d.\n", pNode->Id );
if ( Seq_ObjFaninL1(pNode) < 0 )
printf( "Wrong 1node %d.\n", pNode->Id );
}
// try implementing all the moves at once
Vec_IntForEachEntry( vSteps, Number, i )
{
// get the retiming step
RetStep = Seq_Int2RetStep( Number );
// get the node to be retimed
pNode = Abc_NtkObj( pNtk, RetStep.iNode );
assert( RetStep.nLatches > 0 );
nLatches = RetStep.nLatches;
if ( !fForward )
Abc_ObjRetimeForwardTry( pNode, nLatches );
else
Abc_ObjRetimeBackwardTry( pNode, nLatches );
}
*/
// process the nodes
vMoves = Vec_PtrAlloc( 100 );
while ( Vec_IntSize(vSteps) > 0 )
{
iNode = 0;
fChange = 0;
Vec_IntForEachEntry( vSteps, Number, i )
{
// get the retiming step
RetStep = Seq_Int2RetStep( Number );
// get the node to be retimed
pNode = Abc_NtkObj( pNtk, RetStep.iNode );
assert( RetStep.nLatches > 0 );
// get the number of latches that can be retimed
if ( fForward )
nLatches = Seq_ObjFaninLMin(pNode);
else
nLatches = Seq_ObjFanoutLMin(pNode);
if ( nLatches == 0 )
{
Vec_IntWriteEntry( vSteps, iNode++, Seq_RetStep2Int(RetStep) );
continue;
}
assert( nLatches > 0 );
fChange = 1;
// get the number of latches to be retimed over this node
nLatches = ABC_MIN( nLatches, (int)RetStep.nLatches );
// retime the latches forward
if ( fForward )
Abc_ObjRetimeForwardTry( pNode, nLatches );
else
Abc_ObjRetimeBackwardTry( pNode, nLatches );
// write the moves
for ( k = 0; k < nLatches; k++ )
Vec_PtrPush( vMoves, pNode );
// subtract the retiming performed
RetStep.nLatches -= nLatches;
// store the node if it is not retimed completely
if ( RetStep.nLatches > 0 )
Vec_IntWriteEntry( vSteps, iNode++, Seq_RetStep2Int(RetStep) );
}
// reduce the array
Vec_IntShrink( vSteps, iNode );
if ( !fChange )
{
printf( "Warning: %d strange steps (a minor bug to be fixed later).\n", Vec_IntSize(vSteps) );
/*
Vec_IntForEachEntry( vSteps, Number, i )
{
RetStep = Seq_Int2RetStep( Number );
printf( "%d(%d) ", RetStep.iNode, RetStep.nLatches );
}
printf( "\n" );
*/
break;
}
}
// undo the tentative retiming
if ( fForward )
{
Vec_PtrForEachEntryReverse( vMoves, pNode, i )
Abc_ObjRetimeBackwardTry( pNode, 1 );
}
else
{
Vec_PtrForEachEntryReverse( vMoves, pNode, i )
Abc_ObjRetimeForwardTry( pNode, 1 );
}
return vMoves;
}
/**Function*************************************************************
Synopsis [Splits retiming into forward and backward.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Abc_NtkUtilRetimingSplit( Vec_Str_t * vLags, int fForward )
{
Vec_Int_t * vNodes;
Seq_RetStep_t RetStep;
int Value, i;
vNodes = Vec_IntAlloc( 100 );
Vec_StrForEachEntry( vLags, Value, i )
{
if ( Value < 0 && fForward )
{
RetStep.iNode = i;
RetStep.nLatches = -Value;
Vec_IntPush( vNodes, Seq_RetStep2Int(RetStep) );
}
else if ( Value > 0 && !fForward )
{
RetStep.iNode = i;
RetStep.nLatches = Value;
Vec_IntPush( vNodes, Seq_RetStep2Int(RetStep) );
}
}
return vNodes;
}
/**Function*************************************************************
Synopsis [Retime node forward without initial states.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_ObjRetimeForwardTry( Abc_Obj_t * pObj, int nLatches )
{
Abc_Obj_t * pFanout;
int i;
// make sure it is an AND gate
assert( Abc_ObjFaninNum(pObj) == 2 );
// make sure it has enough latches
// assert( Seq_ObjFaninL0(pObj) >= nLatches );
// assert( Seq_ObjFaninL1(pObj) >= nLatches );
// subtract these latches on the fanin side
Seq_ObjAddFaninL0( pObj, -nLatches );
Seq_ObjAddFaninL1( pObj, -nLatches );
// make sure the label is clean
Abc_ObjForEachFanout( pObj, pFanout, i )
assert( pFanout->fMarkC == 0 );
// add these latches on the fanout side
Abc_ObjForEachFanout( pObj, pFanout, i )
{
if ( pFanout->fMarkC )
continue;
pFanout->fMarkC = 1;
if ( Abc_ObjFaninId0(pFanout) != Abc_ObjFaninId1(pFanout) )
Seq_ObjAddFanoutL( pObj, pFanout, nLatches );
else
{
assert( Abc_ObjFanin0(pFanout) == pObj );
Seq_ObjAddFaninL0( pFanout, nLatches );
Seq_ObjAddFaninL1( pFanout, nLatches );
}
}
// clean the label
Abc_ObjForEachFanout( pObj, pFanout, i )
pFanout->fMarkC = 0;
}
/**Function*************************************************************
Synopsis [Retime node backward without initial states.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_ObjRetimeBackwardTry( Abc_Obj_t * pObj, int nLatches )
{
Abc_Obj_t * pFanout;
int i;
// make sure it is an AND gate
assert( Abc_ObjFaninNum(pObj) == 2 );
// make sure the label is clean
Abc_ObjForEachFanout( pObj, pFanout, i )
assert( pFanout->fMarkC == 0 );
// subtract these latches on the fanout side
Abc_ObjForEachFanout( pObj, pFanout, i )
{
if ( pFanout->fMarkC )
continue;
pFanout->fMarkC = 1;
// assert( Abc_ObjFanoutL(pObj, pFanout) >= nLatches );
if ( Abc_ObjFaninId0(pFanout) != Abc_ObjFaninId1(pFanout) )
Seq_ObjAddFanoutL( pObj, pFanout, -nLatches );
else
{
assert( Abc_ObjFanin0(pFanout) == pObj );
Seq_ObjAddFaninL0( pFanout, -nLatches );
Seq_ObjAddFaninL1( pFanout, -nLatches );
}
}
// clean the label
Abc_ObjForEachFanout( pObj, pFanout, i )
pFanout->fMarkC = 0;
// add these latches on the fanin side
Seq_ObjAddFaninL0( pObj, nLatches );
Seq_ObjAddFaninL1( pObj, nLatches );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////