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/**CFile****************************************************************
FileName [abcRetImpl.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Implementation of retiming.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcRetImpl.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "abcs.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
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 );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Implements the retiming on the sequential AIG.]
Description [Split the retiming into forward and backward.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NtkImplementRetiming( Abc_Ntk_t * pNtk, Vec_Str_t * vLags )
{
Vec_Int_t * vSteps;
Vec_Ptr_t * vMoves;
int RetValue;
// forward retiming
vSteps = Abc_NtkUtilRetimingSplit( vLags, 1 );
// translate each set of steps into moves
vMoves = Abc_NtkUtilRetimingGetMoves( pNtk, vSteps, 1 );
// implement this retiming
Abc_NtkImplementRetimingForward( pNtk, vMoves );
Vec_IntFree( vSteps );
Vec_PtrFree( vMoves );
// backward retiming
vSteps = Abc_NtkUtilRetimingSplit( vLags, 0 );
// translate each set of steps into moves
vMoves = Abc_NtkUtilRetimingGetMoves( pNtk, vSteps, 0 );
// implement this retiming
RetValue = Abc_NtkImplementRetimingBackward( pNtk, vMoves );
Vec_IntFree( vSteps );
Vec_PtrFree( vMoves );
return RetValue;
}
/**Function*************************************************************
Synopsis [Implements the given retiming on the sequential AIG.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_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 [Implements the given retiming on the sequential AIG.]
Description [Returns 0 of initial state computation fails.]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_NtkImplementRetimingBackward( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMoves )
{
Abc_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, Init, nDigits, RetValue, i;
// return if the retiming is trivial
if ( Vec_PtrSize(vMoves) == 0 )
return 1;
// start the table and the array of PO values
tTable = stmm_init_table( stmm_numcmp, stmm_numhash );
vValues = Vec_IntAlloc( 100 );
// create the network for the initial state computation
pNtkProb = Abc_NtkAlloc( ABC_TYPE_LOGIC, ABC_FUNC_SOP );
// perform the backward moves and build the network
Vec_PtrForEachEntry( vMoves, pNode, i )
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
nDigits = Extra_Base10Log( Abc_NtkPiNum(pNtkProb) );
Abc_NtkForEachPi( pNtkProb, pNodeNew, i )
Abc_NtkLogicStoreName( pNodeNew, Abc_ObjNameDummy("pi", i, nDigits) );
nDigits = Extra_Base10Log( Abc_NtkPoNum(pNtkProb) );
Abc_NtkForEachPo( pNtkProb, pNodeNew, i )
Abc_NtkLogicStoreName( pNodeNew, Abc_ObjNameDummy("po", i, nDigits) );
// make sure everything is okay with the network structure
if ( !Abc_NtkDoCheck( pNtkProb ) )
{
printf( "Abc_NtkImplementRetimingBackward: The internal network check has failed.\n" );
return 0;
}
// get the miter cone
pNtkMiter = Abc_NtkCreateCone( pNtkProb, pNtkProb->vCos, vValues );
Abc_NtkDelete( pNtkProb );
Vec_IntFree( vValues );
// 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
RetValue = Abc_NtkMiterSat( pNtkCnf, 30, 0 );
pModel = pNtkCnf->pModel; pNtkCnf->pModel = NULL;
Abc_NtkDelete( pNtkCnf );
// analyze the result
if ( RetValue == -1 || RetValue == 1 )
{
stmm_free_table( tTable );
return 0;
}
// set the values of the latches
i = 0;
stmm_foreach_item( tTable, gen, (char **)&RetEdge, (char **)&pNodeNew )
{
pNode = Abc_NtkObj( pNtk, RetEdge.iNode );
Init = pModel[i]? ABC_INIT_ONE : ABC_INIT_ZERO;
Abc_ObjFaninLSetInitOne( pNode, RetEdge.iEdge, RetEdge.iLatch, Init );
i++;
}
stmm_free_table( tTable );
free( pModel );
return 1;
}
/**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( Abc_ObjFaninL0(pObj) >= 1 );
assert( Abc_ObjFaninL1(pObj) >= 1 );
// remove the init values from the fanins
Init0 = Abc_ObjFaninLDeleteFirst( pObj, 0 );
Init1 = Abc_ObjFaninLDeleteFirst( 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;
// add the init values to the fanouts
Abc_ObjForEachFanout( pObj, pFanout, i )
Abc_ObjFaninLInsertLast( pFanout, Abc_ObjEdgeNum(pFanout, pObj), Init );
}
/**Function*************************************************************
Synopsis [Retimes node backward by one latch.]
Description [Constructs the problem for initial state computation.]
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;
Abc_RetEdge_t Edge;
Abc_Obj_t * pNodeNew, * pFanoutNew, * pBuf;
unsigned Entry;
int i, fMet0, fMet1, fMetX;
// make sure the node can be retimed
assert( Abc_ObjFanoutLMin(pObj) > 0 );
// get the fanout values
fMet0 = fMet1 = fMetX = 0;
Abc_ObjForEachFanout( pObj, pFanout, i )
{
Init = Abc_ObjFaninLGetInitLast( pFanout, Abc_ObjEdgeNum(pObj, pFanout) );
if ( Init == ABC_INIT_ZERO )
fMet0 = 1;
else if ( Init == ABC_INIT_ONE )
fMet1 = 1;
else if ( Init == ABC_INIT_NONE )
fMetX = 1;
}
// quit if conflict is found
if ( fMet0 && fMet1 )
return 0;
// get the new initial value
if ( !fMet0 && !fMet1 && !fMetX )
{
Init = ABC_INIT_DC;
// do not add the node
pNodeNew = NULL;
}
else
{
Init = ABC_INIT_NONE;
// add the node to the network
pNodeNew = Abc_NtkCreateNode( pNtkNew );
pNodeNew->pData = Abc_SopCreateAnd2( pNtkNew->pManFunc, Abc_ObjFaninC0(pObj), Abc_ObjFaninC1(pObj) );
}
// perform the changes
Abc_ObjForEachFanout( pObj, pFanout, i )
{
Edge.iNode = pFanout->Id;
Edge.iEdge = Abc_ObjEdgeNum(pObj, pFanout);
Edge.iLatch = Abc_ObjFaninL( pFanout, Edge.iEdge ) - 1;
// try to delete this edge
stmm_delete( tTable, (char **)&Edge, (char **)&pFanoutNew );
// delete the entry
Value = Abc_ObjFaninLDeleteLast( pFanout, Edge.iEdge );
if ( Value == ABC_INIT_NONE )
Abc_ObjAddFanin( pFanoutNew, pNodeNew );
}
// update the table for each of the edges
Abc_ObjFaninLForEachValue( pObj, 0, Entry, i, Value )
{
if ( Value != ABC_INIT_NONE )
continue;
if ( !stmm_delete( tTable, (char **)&Edge, (char **)&pFanoutNew ) )
assert( 0 );
Edge.iLatch++;
if ( stmm_insert( tTable, (char *)Abc_RetEdge2Int(Edge), (char *)pFanoutNew ) )
assert( 0 );
}
Abc_ObjFaninLForEachValue( pObj, 1, Entry, i, Value )
{
if ( Value != ABC_INIT_NONE )
continue;
if ( !stmm_delete( tTable, (char **)&Edge, (char **)&pFanoutNew ) )
assert( 0 );
Edge.iLatch++;
if ( stmm_insert( tTable, (char *)Abc_RetEdge2Int(Edge), (char *)pFanoutNew ) )
assert( 0 );
}
Abc_ObjFaninLInsertFirst( pObj, 0, Init );
Abc_ObjFaninLInsertFirst( pObj, 1, Init );
// do not insert the don't-care node into the network
if ( Init == ABC_INIT_DC )
return 1;
// add the buffer
pBuf = Abc_NtkCreateNode( pNtkNew );
pBuf->pData = Abc_SopCreateBuf( pNtkNew->pManFunc );
Abc_ObjAddFanin( pNodeNew, pBuf );
// point to it from the table
Edge.iNode = pObj->Id;
Edge.iEdge = 0;
Edge.iLatch = 0;
if ( stmm_insert( tTable, (char *)Abc_RetEdge2Int(Edge), (char *)pBuf ) )
assert( 0 );
// add the buffer
pBuf = Abc_NtkCreateNode( pNtkNew );
pBuf->pData = Abc_SopCreateBuf( pNtkNew->pManFunc );
Abc_ObjAddFanin( pNodeNew, pBuf );
// point to it from the table
Edge.iNode = pObj->Id;
Edge.iEdge = 1;
Edge.iLatch = 0;
if ( stmm_insert( tTable, (char *)Abc_RetEdge2Int(Edge), (char *)pBuf ) )
assert( 0 );
// check if the output value is required
if ( fMet0 || fMet1 )
{
// add the PO and the value
Abc_ObjAddFanin( Abc_NtkCreatePo(pNtkNew), pNodeNew );
Vec_IntPush( vValues, fMet1 );
}
return 1;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
