/**CFile****************************************************************
FileName [lpkAbcMux.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Fast Boolean matching for LUT structures.]
Synopsis [LUT-decomposition based on recursive MUX decomposition.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - April 28, 2007.]
Revision [$Id: lpkAbcMux.c,v 1.00 2007/04/28 00:00:00 alanmi Exp $]
***********************************************************************/
#include "lpkInt.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Checks the possibility of MUX decomposition.]
Description [Returns the best variable to use for MUX decomposition.]
SideEffects []
SeeAlso []
***********************************************************************/
Lpk_Res_t * Lpk_MuxAnalize( Lpk_Man_t * pMan, Lpk_Fun_t * p )
{
static Lpk_Res_t Res, * pRes = &Res;
int nSuppSize0, nSuppSize1, nSuppSizeS, nSuppSizeL;
int Var, Area, Polarity, Delay, Delay0, Delay1, DelayA, DelayB;
memset( pRes, 0, sizeof(Lpk_Res_t) );
assert( p->uSupp == Kit_BitMask(p->nVars) );
assert( p->fSupports );
// derive the delay and area after MUX-decomp with each var - and find the best var
pRes->Variable = -1;
Lpk_SuppForEachVar( p->uSupp, Var )
{
nSuppSize0 = Kit_WordCountOnes(p->puSupps[2*Var+0]);
nSuppSize1 = Kit_WordCountOnes(p->puSupps[2*Var+1]);
assert( nSuppSize0 < (int)p->nVars );
assert( nSuppSize1 < (int)p->nVars );
if ( nSuppSize0 < 1 || nSuppSize1 < 1 )
continue;
//printf( "%d %d ", nSuppSize0, nSuppSize1 );
if ( nSuppSize0 <= (int)p->nLutK - 2 && nSuppSize1 <= (int)p->nLutK - 2 )
{
// include cof var into 0-block
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+0] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+1] , p->pDelays );
Delay0 = Abc_MaxInt( DelayA, DelayB + 1 );
// include cof var into 1-block
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+1] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+0] , p->pDelays );
Delay1 = Abc_MaxInt( DelayA, DelayB + 1 );
// get the best delay
Delay = Abc_MinInt( Delay0, Delay1 );
Area = 2;
Polarity = (int)(Delay == Delay1);
}
else if ( nSuppSize0 <= (int)p->nLutK - 2 )
{
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+0] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+1] , p->pDelays );
Delay = Abc_MaxInt( DelayA, DelayB + 1 );
Area = 1 + Lpk_LutNumLuts( nSuppSize1, p->nLutK );
Polarity = 0;
}
else if ( nSuppSize1 <= (int)p->nLutK - 2 )
{
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+1] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+0] , p->pDelays );
Delay = Abc_MaxInt( DelayA, DelayB + 1 );
Area = 1 + Lpk_LutNumLuts( nSuppSize0, p->nLutK );
Polarity = 1;
}
else if ( nSuppSize0 <= (int)p->nLutK )
{
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+1] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+0] , p->pDelays );
Delay = Abc_MaxInt( DelayA, DelayB + 1 );
Area = 1 + Lpk_LutNumLuts( nSuppSize1+2, p->nLutK );
Polarity = 1;
}
else if ( nSuppSize1 <= (int)p->nLutK )
{
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+0] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+1] , p->pDelays );
Delay = Abc_MaxInt( DelayA, DelayB + 1 );
Area = 1 + Lpk_LutNumLuts( nSuppSize0+2, p->nLutK );
Polarity = 0;
}
else
{
// include cof var into 0-block
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+0] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+1] , p->pDelays );
Delay0 = Abc_MaxInt( DelayA, DelayB + 1 );
// include cof var into 1-block
DelayA = Lpk_SuppDelay( p->puSupps[2*Var+1] | (1<<Var), p->pDelays );
DelayB = Lpk_SuppDelay( p->puSupps[2*Var+0] , p->pDelays );
Delay1 = Abc_MaxInt( DelayA, DelayB + 1 );
// get the best delay
Delay = Abc_MinInt( Delay0, Delay1 );
if ( Delay == Delay0 )
Area = Lpk_LutNumLuts( nSuppSize0+2, p->nLutK ) + Lpk_LutNumLuts( nSuppSize1, p->nLutK );
else
Area = Lpk_LutNumLuts( nSuppSize1+2, p->nLutK ) + Lpk_LutNumLuts( nSuppSize0, p->nLutK );
Polarity = (int)(Delay == Delay1);
}
// find the best variable
if ( Delay > (int)p->nDelayLim )
continue;
if ( Area > (int)p->nAreaLim )
continue;
nSuppSizeS = Abc_MinInt( nSuppSize0 + 2 *!Polarity, nSuppSize1 + 2 * Polarity );
nSuppSizeL = Abc_MaxInt( nSuppSize0 + 2 *!Polarity, nSuppSize1 + 2 * Polarity );
if ( nSuppSizeL > (int)p->nVars )
continue;
if ( pRes->Variable == -1 || pRes->AreaEst > Area ||
(pRes->AreaEst == Area && pRes->nSuppSizeS + pRes->nSuppSizeL > nSuppSizeS + nSuppSizeL) ||
(pRes->AreaEst == Area && pRes->nSuppSizeS + pRes->nSuppSizeL == nSuppSizeS + nSuppSizeL && pRes->DelayEst > Delay) )
{
pRes->Variable = Var;
pRes->Polarity = Polarity;
pRes->AreaEst = Area;
pRes->DelayEst = Delay;
pRes->nSuppSizeS = nSuppSizeS;
pRes->nSuppSizeL = nSuppSizeL;
}
}
return pRes->Variable == -1 ? NULL : pRes;
}
/**Function*************************************************************
Synopsis [Transforms the function decomposed by the MUX decomposition.]
Description [Returns the best variable to use for MUX decomposition.]
SideEffects []
SeeAlso []
***********************************************************************/
Lpk_Fun_t * Lpk_MuxSplit( Lpk_Man_t * pMan, Lpk_Fun_t * p, int Var, int Pol )
{
Lpk_Fun_t * pNew;
unsigned * pTruth = Lpk_FunTruth( p, 0 );
unsigned * pTruth0 = Lpk_FunTruth( p, 1 );
unsigned * pTruth1 = Lpk_FunTruth( p, 2 );
// unsigned uSupp;
int iVarVac;
assert( Var >= 0 && Var < (int)p->nVars );
assert( p->nAreaLim >= 2 );
assert( p->uSupp == Kit_BitMask(p->nVars) );
Kit_TruthCofactor0New( pTruth0, pTruth, p->nVars, Var );
Kit_TruthCofactor1New( pTruth1, pTruth, p->nVars, Var );
/*
uSupp = Kit_TruthSupport( pTruth, p->nVars );
Extra_PrintBinary( stdout, &uSupp, 16 ); printf( "\n" );
uSupp = Kit_TruthSupport( pTruth0, p->nVars );
Extra_PrintBinary( stdout, &uSupp, 16 ); printf( "\n" );
uSupp = Kit_TruthSupport( pTruth1, p->nVars );
Extra_PrintBinary( stdout, &uSupp, 16 ); printf( "\n\n" );
*/
// derive the new component
pNew = Lpk_FunDup( p, Pol ? pTruth0 : pTruth1 );
// update the support of the old component
p->uSupp = Kit_TruthSupport( Pol ? pTruth1 : pTruth0, p->nVars );
p->uSupp |= (1 << Var);
// update the truth table of the old component
iVarVac = Kit_WordFindFirstBit( ~p->uSupp );
assert( iVarVac < (int)p->nVars );
p->uSupp |= (1 << iVarVac);
Kit_TruthIthVar( pTruth, p->nVars, iVarVac );
if ( Pol )
Kit_TruthMuxVar( pTruth, pTruth, pTruth1, p->nVars, Var );
else
Kit_TruthMuxVar( pTruth, pTruth0, pTruth, p->nVars, Var );
assert( p->uSupp == Kit_TruthSupport(pTruth, p->nVars) );
// set the decomposed variable
p->pFanins[iVarVac] = pNew->Id;
p->pDelays[iVarVac] = p->nDelayLim - 1;
// support minimize both
p->fSupports = 0;
Lpk_FunSuppMinimize( p );
Lpk_FunSuppMinimize( pNew );
// update delay and area requirements
pNew->nDelayLim = p->nDelayLim - 1;
if ( pNew->nVars <= pNew->nLutK )
{
pNew->nAreaLim = 1;
p->nAreaLim = p->nAreaLim - 1;
}
else if ( p->nVars <= p->nLutK )
{
pNew->nAreaLim = p->nAreaLim - 1;
p->nAreaLim = 1;
}
else if ( p->nVars < pNew->nVars )
{
pNew->nAreaLim = p->nAreaLim / 2 + p->nAreaLim % 2;
p->nAreaLim = p->nAreaLim / 2 - p->nAreaLim % 2;
}
else // if ( pNew->nVars < p->nVars )
{
pNew->nAreaLim = p->nAreaLim / 2 - p->nAreaLim % 2;
p->nAreaLim = p->nAreaLim / 2 + p->nAreaLim % 2;
}
pNew->fMark = 1;
return pNew;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END