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abc/src/base/seq/seqFpgaIter.c

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/**CFile****************************************************************
FileName [seqFpgaIter.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Construction and manipulation of sequential AIGs.]
Synopsis [Iterative delay computation in FPGA mapping/retiming package.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: seqFpgaIter.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "seqInt.h"
#include "main.h"
#include "fpga.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
static void Seq_FpgaMappingCollectNode_rec( Abc_Obj_t * pAnd, Vec_Ptr_t * vMapping, Vec_Vec_t * vMapCuts );
static Cut_Cut_t * Seq_FpgaMappingSelectCut( Abc_Obj_t * pAnd );
extern Cut_Man_t * Abc_NtkSeqCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams );
extern Cut_Man_t * Abc_NtkCuts( Abc_Ntk_t * pNtk, Cut_Params_t * pParams );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Computes the retiming lags for FPGA mapping.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Seq_FpgaMappingDelays( Abc_Ntk_t * pNtk, int fVerbose )
{
Abc_Seq_t * p = pNtk->pManFunc;
Cut_Params_t Params, * pParams = &Params;
Abc_Obj_t * pObj;
int i, clk;
// set defaults for cut computation
memset( pParams, 0, sizeof(Cut_Params_t) );
pParams->nVarsMax = p->nVarsMax; // the max cut size ("k" of the k-feasible cuts)
pParams->nKeepMax = 1000; // the max number of cuts kept at a node
pParams->fTruth = 0; // compute truth tables
pParams->fFilter = 1; // filter dominated cuts
pParams->fSeq = 1; // compute sequential cuts
pParams->fVerbose = fVerbose; // the verbosiness flag
// compute the cuts
clk = clock();
p->pCutMan = Abc_NtkSeqCuts( pNtk, pParams );
// pParams->fSeq = 0;
// p->pCutMan = Abc_NtkCuts( pNtk, pParams );
p->timeCuts = clock() - clk;
if ( fVerbose )
Cut_ManPrintStats( p->pCutMan );
// compute area flows
// Seq_MapComputeAreaFlows( pNtk, fVerbose );
// compute the delays
clk = clock();
if ( !Seq_AigRetimeDelayLags( pNtk, fVerbose ) )
return 0;
p->timeDelay = clock() - clk;
// collect the nodes and cuts used in the mapping
p->vMapAnds = Vec_PtrAlloc( 1000 );
p->vMapCuts = Vec_VecAlloc( 1000 );
Abc_NtkIncrementTravId( pNtk );
Abc_NtkForEachPo( pNtk, pObj, i )
Seq_FpgaMappingCollectNode_rec( Abc_ObjFanin0(pObj), p->vMapAnds, p->vMapCuts );
if ( fVerbose )
printf( "The number of LUTs = %d.\n", Vec_PtrSize(p->vMapAnds) );
// remove the cuts
Cut_ManStop( p->pCutMan );
p->pCutMan = NULL;
return 1;
}
/**Function*************************************************************
Synopsis [Derives the parameters of the best mapping/retiming for one node.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Seq_FpgaMappingCollectNode_rec( Abc_Obj_t * pAnd, Vec_Ptr_t * vMapping, Vec_Vec_t * vMapCuts )
{
Abc_Obj_t * pFanin;
Cut_Cut_t * pCutBest;
int k;
// skip if this is a non-PI node
if ( !Abc_AigNodeIsAnd(pAnd) )
return;
// skip a visited node
if ( Abc_NodeIsTravIdCurrent(pAnd) )
return;
Abc_NodeSetTravIdCurrent(pAnd);
// visit the fanins of the node
pCutBest = Seq_FpgaMappingSelectCut( pAnd );
for ( k = 0; k < (int)pCutBest->nLeaves; k++ )
{
pFanin = Abc_NtkObj( pAnd->pNtk, pCutBest->pLeaves[k] >> 8 );
Seq_FpgaMappingCollectNode_rec( pFanin, vMapping, vMapCuts );
}
// add this node
Vec_PtrPush( vMapping, pAnd );
for ( k = 0; k < (int)pCutBest->nLeaves; k++ )
Vec_VecPush( vMapCuts, Vec_PtrSize(vMapping)-1, (void *)pCutBest->pLeaves[k] );
}
/**Function*************************************************************
Synopsis [Selects the best cut to represent the node in the mapping.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Cut_Cut_t * Seq_FpgaMappingSelectCut( Abc_Obj_t * pAnd )
{
Abc_Obj_t * pFanin;
Cut_Cut_t * pCut, * pCutBest, * pList;
float CostCur, CostMin = ABC_INFINITY;
int ArrivalCut, ArrivalMin, i;
// get the arrival time of the best non-trivial cut
ArrivalMin = Seq_NodeGetLValue( pAnd );
// iterate through the cuts and select the one with the minimum cost
pList = Abc_NodeReadCuts( Seq_NodeCutMan(pAnd), pAnd );
CostMin = ABC_INFINITY;
pCutBest = NULL;
for ( pCut = pList->pNext; pCut; pCut = pCut->pNext )
{
ArrivalCut = *((int *)&pCut->uSign);
// assert( ArrivalCut >= ArrivalMin );
if ( ArrivalCut > ArrivalMin )
continue;
CostCur = 0.0;
for ( i = 0; i < (int)pCut->nLeaves; i++ )
{
pFanin = Abc_NtkObj( pAnd->pNtk, pCut->pLeaves[i] >> 8 );
if ( Abc_ObjIsPi(pFanin) )
continue;
if ( Abc_NodeIsTravIdCurrent(pFanin) )
continue;
CostCur += (float)(1.0 / Abc_ObjFanoutNum(pFanin));
// CostCur += Seq_NodeGetFlow( pFanin );
}
if ( CostMin > CostCur )
{
CostMin = CostCur;
pCutBest = pCut;
}
}
assert( pCutBest != NULL );
return pCutBest;
}
/**Function*************************************************************
Synopsis [Computes the l-value of the cut.]
Description [The node should be internal.]
SideEffects []
SeeAlso []
***********************************************************************/
static inline int Seq_FpgaCutUpdateLValue( Cut_Cut_t * pCut, Abc_Obj_t * pObj, int Fi )
{
Abc_Obj_t * pFanin;
int i, lValueMax, lValueCur;
assert( Abc_AigNodeIsAnd(pObj) );
lValueMax = -ABC_INFINITY;
for ( i = 0; i < (int)pCut->nLeaves; i++ )
{
// lValue0 = Seq_NodeGetLValue(Abc_ObjFanin0(pObj)) - Fi * Abc_ObjFaninL0(pObj);
pFanin = Abc_NtkObj(pObj->pNtk, pCut->pLeaves[i] >> 8);
lValueCur = Seq_NodeGetLValue(pFanin) - Fi * (pCut->pLeaves[i] & 255);
if ( lValueMax < lValueCur )
lValueMax = lValueCur;
}
lValueMax += 1;
*((int *)&pCut->uSign) = lValueMax;
return lValueMax;
}
/**Function*************************************************************
Synopsis [Computes the l-value of the node.]
Description [The node can be internal or a PO.]
SideEffects []
SeeAlso []
***********************************************************************/
int Seq_FpgaNodeUpdateLValue( Abc_Obj_t * pObj, int Fi )
{
Cut_Cut_t * pCut, * pList;
int lValueNew, lValueOld, lValueCut;
assert( !Abc_ObjIsPi(pObj) );
assert( Abc_ObjFaninNum(pObj) > 0 );
if ( Abc_ObjIsPo(pObj) )
{
lValueNew = Seq_NodeGetLValue(Abc_ObjFanin0(pObj)) - Fi * Seq_ObjFaninL0(pObj);
return (lValueNew > Fi)? SEQ_UPDATE_FAIL : SEQ_UPDATE_NO;
}
// get the arrival time of the best non-trivial cut
pList = Abc_NodeReadCuts( Seq_NodeCutMan(pObj), pObj );
// skip the choice nodes
if ( pList == NULL )
return SEQ_UPDATE_NO;
lValueNew = ABC_INFINITY;
for ( pCut = pList->pNext; pCut; pCut = pCut->pNext )
{
lValueCut = Seq_FpgaCutUpdateLValue( pCut, pObj, Fi );
if ( lValueNew > lValueCut )
lValueNew = lValueCut;
}
// compare the arrival time with the previous arrival time
lValueOld = Seq_NodeGetLValue(pObj);
// if ( lValueNew == lValueOld )
if ( lValueNew <= lValueOld )
return SEQ_UPDATE_NO;
Seq_NodeSetLValue( pObj, lValueNew );
//printf( "%d -> %d ", lValueOld, lValueNew );
return SEQ_UPDATE_YES;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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