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abc/src/base/abci/abcLutmin.c

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/**CFile****************************************************************
FileName [abcLutmin.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [Network and node package.]
Synopsis [Minimization of the number of LUTs.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - June 20, 2005.]
Revision [$Id: abcLutmin.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
***********************************************************************/
#include "base/abc/abc.h"
#ifdef ABC_USE_CUDD
#include "bdd/extrab/extraBdd.h"
#endif
ABC_NAMESPACE_IMPL_START
/*
Implememented here is the algorithm for minimal-LUT decomposition
described in the paper: T. Sasao et al. "On the number of LUTs
to implement logic functions", To appear in Proc. IWLS'09.
*/
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
#ifdef ABC_USE_CUDD
/**Function*************************************************************
Synopsis [Check if a LUT can absort a fanin.]
Description [The fanins are (c, d0, d1).]
SideEffects []
SeeAlso []
***********************************************************************/
int Abc_ObjCheckAbsorb( Abc_Obj_t * pObj, Abc_Obj_t * pPivot, int nLutSize, Vec_Ptr_t * vFanins )
{
Abc_Obj_t * pFanin;
int i;
assert( Abc_ObjIsNode(pObj) && Abc_ObjIsNode(pPivot) );
// add fanins of the node
Vec_PtrClear( vFanins );
Abc_ObjForEachFanin( pObj, pFanin, i )
if ( pFanin != pPivot )
Vec_PtrPush( vFanins, pFanin );
// add fanins of the fanin
Abc_ObjForEachFanin( pPivot, pFanin, i )
{
Vec_PtrPushUnique( vFanins, pFanin );
if ( Vec_PtrSize(vFanins) > nLutSize )
return 0;
}
return 1;
}
/**Function*************************************************************
Synopsis [Check how many times a LUT can absorb a fanin.]
Description [The fanins are (c, d0, d1).]
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkCheckAbsorb( Abc_Ntk_t * pNtk, int nLutSize )
{
Vec_Int_t * vCounts;
Vec_Ptr_t * vFanins;
Abc_Obj_t * pObj, * pFanin;
int i, k, Counter = 0, Counter2 = 0;
abctime clk = Abc_Clock();
vCounts = Vec_IntStart( Abc_NtkObjNumMax(pNtk) );
vFanins = Vec_PtrAlloc( 100 );
Abc_NtkForEachNode( pNtk, pObj, i )
Abc_ObjForEachFanin( pObj, pFanin, k )
if ( Abc_ObjIsNode(pFanin) && Abc_ObjCheckAbsorb( pObj, pFanin, nLutSize, vFanins ) )
{
Vec_IntAddToEntry( vCounts, Abc_ObjId(pFanin), 1 );
Counter++;
}
Vec_PtrFree( vFanins );
Abc_NtkForEachNode( pNtk, pObj, i )
if ( Vec_IntEntry(vCounts, Abc_ObjId(pObj)) == Abc_ObjFanoutNum(pObj) )
{
// printf( "%d ", Abc_ObjId(pObj) );
Counter2++;
}
printf( "Absorted = %6d. (%6.2f %%) Fully = %6d. (%6.2f %%) ",
Counter, 100.0 * Counter / Abc_NtkNodeNum(pNtk),
Counter2, 100.0 * Counter2 / Abc_NtkNodeNum(pNtk) );
Abc_PrintTime( 1, "Time", Abc_Clock() - clk );
}
/**Function*************************************************************
Synopsis [Implements 2:1 MUX using one 3-LUT.]
Description [The fanins are (c, d0, d1).]
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddMux21( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pFanins[] )
{
DdManager * dd = (DdManager *)pNtkNew->pManFunc;
Abc_Obj_t * pNode;
DdNode * bSpin, * bCof0, * bCof1;
pNode = Abc_NtkCreateNode( pNtkNew );
Abc_ObjAddFanin( pNode, pFanins[0] );
Abc_ObjAddFanin( pNode, pFanins[1] );
Abc_ObjAddFanin( pNode, pFanins[2] );
bSpin = Cudd_bddIthVar(dd, 0);
bCof0 = Cudd_bddIthVar(dd, 1);
bCof1 = Cudd_bddIthVar(dd, 2);
pNode->pData = Cudd_bddIte( dd, bSpin, bCof1, bCof0 ); Cudd_Ref( (DdNode *)pNode->pData );
return pNode;
}
/**Function*************************************************************
Synopsis [Implements 4:1 MUX using one 6-LUT.]
Description [The fanins are (c0, c1, d00, d01, d10, d11).]
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddMux411( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pFanins[] )
{
DdManager * dd = (DdManager *)pNtkNew->pManFunc;
Abc_Obj_t * pNode;
DdNode * bSpin, * bCof0, * bCof1;
pNode = Abc_NtkCreateNode( pNtkNew );
Abc_ObjAddFanin( pNode, pFanins[0] );
Abc_ObjAddFanin( pNode, pFanins[1] );
Abc_ObjAddFanin( pNode, pFanins[2] );
Abc_ObjAddFanin( pNode, pFanins[3] );
Abc_ObjAddFanin( pNode, pFanins[4] );
Abc_ObjAddFanin( pNode, pFanins[5] );
bSpin = Cudd_bddIthVar(dd, 1);
bCof0 = Cudd_bddIte( dd, bSpin, Cudd_bddIthVar(dd, 3), Cudd_bddIthVar(dd, 2) ); Cudd_Ref( bCof0 );
bCof1 = Cudd_bddIte( dd, bSpin, Cudd_bddIthVar(dd, 5), Cudd_bddIthVar(dd, 4) ); Cudd_Ref( bCof1 );
bSpin = Cudd_bddIthVar(dd, 0);
pNode->pData = Cudd_bddIte( dd, bSpin, bCof1, bCof0 ); Cudd_Ref( (DdNode *)pNode->pData );
Cudd_RecursiveDeref( dd, bCof0 );
Cudd_RecursiveDeref( dd, bCof1 );
return pNode;
}
/**Function*************************************************************
Synopsis [Implementes 4:1 MUX using two 4-LUTs.]
Description [The fanins are (c0, c1, d00, d01, d10, d11).]
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddMux412( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pFanins[] )
{
DdManager * dd = (DdManager *)pNtkNew->pManFunc;
Abc_Obj_t * pNodeBot, * pNodeTop;
DdNode * bSpin, * bCof0, * bCof1;
// bottom node
pNodeBot = Abc_NtkCreateNode( pNtkNew );
Abc_ObjAddFanin( pNodeBot, pFanins[0] );
Abc_ObjAddFanin( pNodeBot, pFanins[1] );
Abc_ObjAddFanin( pNodeBot, pFanins[2] );
Abc_ObjAddFanin( pNodeBot, pFanins[3] );
bSpin = Cudd_bddIthVar(dd, 0);
bCof0 = Cudd_bddIte( dd, Cudd_bddIthVar(dd, 1), Cudd_bddIthVar(dd, 3), Cudd_bddIthVar(dd, 2) ); Cudd_Ref( bCof0 );
bCof1 = Cudd_bddIthVar(dd, 1);
pNodeBot->pData = Cudd_bddIte( dd, bSpin, bCof1, bCof0 ); Cudd_Ref( (DdNode *)pNodeBot->pData );
Cudd_RecursiveDeref( dd, bCof0 );
// top node
pNodeTop = Abc_NtkCreateNode( pNtkNew );
Abc_ObjAddFanin( pNodeTop, pFanins[0] );
Abc_ObjAddFanin( pNodeTop, pNodeBot );
Abc_ObjAddFanin( pNodeTop, pFanins[4] );
Abc_ObjAddFanin( pNodeTop, pFanins[5] );
bSpin = Cudd_bddIthVar(dd, 0);
bCof0 = Cudd_bddIthVar(dd, 1);
bCof1 = Cudd_bddIte( dd, Cudd_bddIthVar(dd, 1), Cudd_bddIthVar(dd, 3), Cudd_bddIthVar(dd, 2) ); Cudd_Ref( bCof1 );
pNodeTop->pData = Cudd_bddIte( dd, bSpin, bCof1, bCof0 ); Cudd_Ref( (DdNode *)pNodeTop->pData );
Cudd_RecursiveDeref( dd, bCof1 );
return pNodeTop;
}
/**Function*************************************************************
Synopsis [Implementes 4:1 MUX using two 4-LUTs.]
Description [The fanins are (c0, c1, d00, d01, d10, d11).]
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddMux412a( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pFanins[] )
{
DdManager * dd = (DdManager *)pNtkNew->pManFunc;
Abc_Obj_t * pNodeBot, * pNodeTop;
DdNode * bSpin, * bCof0, * bCof1;
// bottom node
pNodeBot = Abc_NtkCreateNode( pNtkNew );
Abc_ObjAddFanin( pNodeBot, pFanins[1] );
Abc_ObjAddFanin( pNodeBot, pFanins[2] );
Abc_ObjAddFanin( pNodeBot, pFanins[3] );
bSpin = Cudd_bddIthVar(dd, 0);
bCof0 = Cudd_bddIthVar(dd, 1);
bCof1 = Cudd_bddIthVar(dd, 2);
pNodeBot->pData = Cudd_bddIte( dd, bSpin, bCof1, bCof0 ); Cudd_Ref( (DdNode *)pNodeBot->pData );
// top node
pNodeTop = Abc_NtkCreateNode( pNtkNew );
Abc_ObjAddFanin( pNodeTop, pFanins[0] );
Abc_ObjAddFanin( pNodeTop, pFanins[1] );
Abc_ObjAddFanin( pNodeTop, pNodeBot );
Abc_ObjAddFanin( pNodeTop, pFanins[4] );
Abc_ObjAddFanin( pNodeTop, pFanins[5] );
bSpin = Cudd_bddIthVar(dd, 0);
bCof0 = Cudd_bddIthVar(dd, 2);
bCof1 = Cudd_bddIte( dd, Cudd_bddIthVar(dd, 1), Cudd_bddIthVar(dd, 4), Cudd_bddIthVar(dd, 3) ); Cudd_Ref( bCof1 );
pNodeTop->pData = Cudd_bddIte( dd, bSpin, bCof1, bCof0 ); Cudd_Ref( (DdNode *)pNodeTop->pData );
Cudd_RecursiveDeref( dd, bCof1 );
return pNodeTop;
}
/**Function*************************************************************
Synopsis [Implements 4:1 MUX using three 2:1 MUXes.]
Description [The fanins are (c0, c1, d00, d01, d10, d11).]
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddMux413( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pFanins[] )
{
Abc_Obj_t * pNodesBot[3], * pNodesTop[3];
// left bottom
pNodesBot[0] = pFanins[1];
pNodesBot[1] = pFanins[2];
pNodesBot[2] = pFanins[3];
pNodesTop[1] = Abc_NtkBddMux21( pNtkNew, pNodesBot );
// right bottom
pNodesBot[0] = pFanins[1];
pNodesBot[1] = pFanins[4];
pNodesBot[2] = pFanins[5];
pNodesTop[2] = Abc_NtkBddMux21( pNtkNew, pNodesBot );
// top node
pNodesTop[0] = pFanins[0];
return Abc_NtkBddMux21( pNtkNew, pNodesTop );
}
/**Function*************************************************************
Synopsis [Finds unique cofactors of the function on the given level.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
DdNode * Abc_NtkBddCofactors_rec( DdManager * dd, DdNode * bNode, int iCof, int iLevel, int nLevels )
{
DdNode * bNode0, * bNode1;
if ( Cudd_IsConstant(bNode) || iLevel == nLevels )
return bNode;
if ( Cudd_ReadPerm( dd, Cudd_NodeReadIndex(bNode) ) > iLevel )
{
bNode0 = bNode;
bNode1 = bNode;
}
else if ( Cudd_IsComplement(bNode) )
{
bNode0 = Cudd_Not(cuddE(Cudd_Regular(bNode)));
bNode1 = Cudd_Not(cuddT(Cudd_Regular(bNode)));
}
else
{
bNode0 = cuddE(bNode);
bNode1 = cuddT(bNode);
}
if ( (iCof >> (nLevels-1-iLevel)) & 1 )
return Abc_NtkBddCofactors_rec( dd, bNode1, iCof, iLevel + 1, nLevels );
return Abc_NtkBddCofactors_rec( dd, bNode0, iCof, iLevel + 1, nLevels );
}
/**Function*************************************************************
Synopsis [Finds unique cofactors of the function on the given level.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Ptr_t * Abc_NtkBddCofactors( DdManager * dd, DdNode * bNode, int Level )
{
Vec_Ptr_t * vCofs;
int i, nCofs = (1<<Level);
assert( Level > 0 && Level < 10 );
vCofs = Vec_PtrAlloc( 8 );
for ( i = 0; i < nCofs; i++ )
Vec_PtrPush( vCofs, Abc_NtkBddCofactors_rec( dd, bNode, i, 0, Level ) );
return vCofs;
}
/**Function*************************************************************
Synopsis [Comparison procedure for two integers.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static int Vec_PtrSortCompare( void ** pp1, void ** pp2 )
{
if ( *pp1 < *pp2 )
return -1;
if ( *pp1 > *pp2 )
return 1;
return 0;
}
/**Function*************************************************************
Synopsis [Converts the node to MUXes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkCreateCofLut( Abc_Ntk_t * pNtkNew, DdManager * dd, DdNode * bCof, Abc_Obj_t * pNode, int Level )
{
int fVerbose = 0;
DdNode * bFuncNew;
Abc_Obj_t * pNodeNew;
int i;
assert( Abc_ObjFaninNum(pNode) > Level );
// create a new node
pNodeNew = Abc_NtkCreateNode( pNtkNew );
// add the fanins in the order, in which they appear in the reordered manager
for ( i = Level; i < Abc_ObjFaninNum(pNode); i++ )
Abc_ObjAddFanin( pNodeNew, Abc_ObjFanin(pNode, i)->pCopy );
if ( fVerbose )
{
Extra_bddPrint( dd, bCof );
printf( "\n" );
printf( "\n" );
}
// transfer the function
bFuncNew = Extra_bddMove( dd, bCof, -Level ); Cudd_Ref( bFuncNew );
if ( fVerbose )
{
Extra_bddPrint( dd, bFuncNew );
printf( "\n" );
printf( "\n" );
}
pNodeNew->pData = Extra_TransferLevelByLevel( dd, (DdManager *)pNtkNew->pManFunc, bFuncNew ); Cudd_Ref( (DdNode *)pNodeNew->pData );
//Extra_bddPrint( pNtkNew->pManFunc, pNodeNew->pData );
//printf( "\n" );
//printf( "\n" );
Cudd_RecursiveDeref( dd, bFuncNew );
return pNodeNew;
}
/**Function*************************************************************
Synopsis [Performs one step of Ashenhurst-Curtis decomposition.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddCurtis( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pNode, Vec_Ptr_t * vCofs, Vec_Ptr_t * vUniq )
{
DdManager * ddOld = (DdManager *)pNode->pNtk->pManFunc;
DdManager * ddNew = (DdManager *)pNtkNew->pManFunc;
DdNode * bCof, * bUniq, * bMint, * bTemp, * bFunc, * bBits[10], ** pbCodeVars;
Abc_Obj_t * pNodeNew = NULL, * pNodeBS[10];
int nLutSize = Abc_Base2Log( Vec_PtrSize(vCofs) );
int nBits = Abc_Base2Log( Vec_PtrSize(vUniq) );
int b, c, u, i;
assert( nBits + 2 <= nLutSize );
assert( nLutSize < Abc_ObjFaninNum(pNode) );
// start BDDs for the decompoosed blocks
for ( b = 0; b < nBits; b++ )
bBits[b] = Cudd_ReadLogicZero(ddNew), Cudd_Ref( bBits[b] );
// add each bound set minterm to one of the blccks
Vec_PtrForEachEntry( DdNode *, vCofs, bCof, c )
{
Vec_PtrForEachEntry( DdNode *, vUniq, bUniq, u )
if ( bUniq == bCof )
break;
assert( u < Vec_PtrSize(vUniq) );
for ( b = 0; b < nBits; b++ )
{
if ( ((u >> b) & 1) == 0 )
continue;
bMint = Extra_bddBitsToCube( ddNew, c, nLutSize, ddNew->vars, 1 ); Cudd_Ref( bMint );
bBits[b] = Cudd_bddOr( ddNew, bTemp = bBits[b], bMint ); Cudd_Ref( bBits[b] );
Cudd_RecursiveDeref( ddNew, bTemp );
Cudd_RecursiveDeref( ddNew, bMint );
}
}
// create bound set nodes
for ( b = 0; b < nBits; b++ )
{
pNodeBS[b] = Abc_NtkCreateNode( pNtkNew );
for ( i = 0; i < nLutSize; i++ )
Abc_ObjAddFanin( pNodeBS[b], Abc_ObjFanin(pNode, i)->pCopy );
pNodeBS[b]->pData = bBits[b]; // takes ref
}
// create composition node
pNodeNew = Abc_NtkCreateNode( pNtkNew );
// add free set variables first
for ( i = nLutSize; i < Abc_ObjFaninNum(pNode); i++ )
Abc_ObjAddFanin( pNodeNew, Abc_ObjFanin(pNode, i)->pCopy );
// add code bit variables next
for ( b = 0; b < nBits; b++ )
Abc_ObjAddFanin( pNodeNew, pNodeBS[b] );
// derive function of the composition node
bFunc = Cudd_ReadLogicZero(ddNew); Cudd_Ref( bFunc );
pbCodeVars = ddNew->vars + Abc_ObjFaninNum(pNode) - nLutSize;
Vec_PtrForEachEntry( DdNode *, vUniq, bUniq, u )
{
bUniq = Extra_bddMove( ddOld, bUniq, -nLutSize ); Cudd_Ref( bUniq );
bUniq = Extra_TransferLevelByLevel( ddOld, ddNew, bTemp = bUniq ); Cudd_Ref( bUniq );
Cudd_RecursiveDeref( ddOld, bTemp );
bMint = Extra_bddBitsToCube( ddNew, u, nBits, pbCodeVars, 0 ); Cudd_Ref( bMint );
bMint = Cudd_bddAnd( ddNew, bTemp = bMint, bUniq ); Cudd_Ref( bMint );
Cudd_RecursiveDeref( ddNew, bTemp );
Cudd_RecursiveDeref( ddNew, bUniq );
bFunc = Cudd_bddOr( ddNew, bTemp = bFunc, bMint ); Cudd_Ref( bFunc );
Cudd_RecursiveDeref( ddNew, bTemp );
Cudd_RecursiveDeref( ddNew, bMint );
}
pNodeNew->pData = bFunc; // takes ref
return pNodeNew;
}
/**Function*************************************************************
Synopsis [Tries to decompose using cofactoring into two LUTs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddFindCofactor( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pNode, int nLutSize )
{
Abc_Obj_t * pNodeBot, * pNodeTop;
DdManager * ddOld = (DdManager *)pNode->pNtk->pManFunc;
DdManager * ddNew = (DdManager *)pNtkNew->pManFunc;
DdNode * bCof0 = NULL, * bCof1 = NULL, * bSupp, * bTemp, * bVar;
DdNode * bCof0n, * bCof1n;
int i, iCof, iFreeVar, fCof1Smaller = -1;
assert( Abc_ObjFaninNum(pNode) == nLutSize + 1 );
for ( iCof = 0; iCof < Abc_ObjFaninNum(pNode); iCof++ )
{
bVar = Cudd_bddIthVar( ddOld, iCof );
bCof0 = Cudd_Cofactor( ddOld, (DdNode *)pNode->pData, Cudd_Not(bVar) ); Cudd_Ref( bCof0 );
bCof1 = Cudd_Cofactor( ddOld, (DdNode *)pNode->pData, bVar ); Cudd_Ref( bCof1 );
if ( Cudd_SupportSize( ddOld, bCof0 ) <= nLutSize - 2 )
{
fCof1Smaller = 0;
break;
}
if ( Cudd_SupportSize( ddOld, bCof1 ) <= nLutSize - 2 )
{
fCof1Smaller = 1;
break;
}
Cudd_RecursiveDeref( ddOld, bCof0 );
Cudd_RecursiveDeref( ddOld, bCof1 );
}
if ( iCof == Abc_ObjFaninNum(pNode) )
return NULL;
// find unused variable
bSupp = Cudd_Support( ddOld, fCof1Smaller? bCof1 : bCof0 ); Cudd_Ref( bSupp );
iFreeVar = -1;
for ( i = 0; i < Abc_ObjFaninNum(pNode); i++ )
{
assert( i == Cudd_ReadPerm(ddOld, i) );
if ( i == iCof )
continue;
for ( bTemp = bSupp; !Cudd_IsConstant(bTemp); bTemp = cuddT(bTemp) )
if ( i == (int)Cudd_NodeReadIndex(bTemp) )
break;
if ( Cudd_IsConstant(bTemp) )
{
iFreeVar = i;
break;
}
}
assert( iFreeVar != iCof && iFreeVar < Abc_ObjFaninNum(pNode) );
Cudd_RecursiveDeref( ddOld, bSupp );
// transfer the cofactors
bCof0n = Extra_TransferLevelByLevel( ddOld, ddNew, bCof0 ); Cudd_Ref( bCof0n );
bCof1n = Extra_TransferLevelByLevel( ddOld, ddNew, bCof1 ); Cudd_Ref( bCof1n );
Cudd_RecursiveDeref( ddOld, bCof0 );
Cudd_RecursiveDeref( ddOld, bCof1 );
// create bottom node
pNodeBot = Abc_NtkCreateNode( pNtkNew );
for ( i = 0; i < Abc_ObjFaninNum(pNode); i++ )
Abc_ObjAddFanin( pNodeBot, Abc_ObjFanin(pNode, i)->pCopy );
pNodeBot->pData = fCof1Smaller? bCof0n : bCof1n;
// create top node
pNodeTop = Abc_NtkCreateNode( pNtkNew );
for ( i = 0; i < Abc_ObjFaninNum(pNode); i++ )
if ( i == iFreeVar )
Abc_ObjAddFanin( pNodeTop, pNodeBot );
else
Abc_ObjAddFanin( pNodeTop, Abc_ObjFanin(pNode, i)->pCopy );
// derive the new function
pNodeTop->pData = Cudd_bddIte( ddNew,
Cudd_bddIthVar(ddNew, iCof),
fCof1Smaller? bCof1n : Cudd_bddIthVar(ddNew, iFreeVar),
fCof1Smaller? Cudd_bddIthVar(ddNew, iFreeVar) : bCof0n );
Cudd_Ref( (DdNode *)pNodeTop->pData );
Cudd_RecursiveDeref( ddNew, fCof1Smaller? bCof1n : bCof0n );
return pNodeTop;
}
/**Function*************************************************************
Synopsis [Decompose the function once.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Obj_t * Abc_NtkBddDecompose( Abc_Ntk_t * pNtkNew, Abc_Obj_t * pNode, int nLutSize, int fVerbose )
{
Vec_Ptr_t * vCofs, * vUniq;
DdManager * dd = (DdManager *)pNode->pNtk->pManFunc;
DdNode * bCof;
Abc_Obj_t * pNodeNew = NULL;
Abc_Obj_t * pCofs[20];
int i;
assert( Abc_ObjFaninNum(pNode) > nLutSize );
// try to decompose with two LUTs (the best case for Supp = LutSize + 1)
if ( Abc_ObjFaninNum(pNode) == nLutSize + 1 )
{
pNodeNew = Abc_NtkBddFindCofactor( pNtkNew, pNode, nLutSize );
if ( pNodeNew != NULL )
{
if ( fVerbose )
printf( "Decomposing %d-input node %d using MUX.\n",
Abc_ObjFaninNum(pNode), Abc_ObjId(pNode) );
return pNodeNew;
}
}
// cofactor w.r.t. the bound set variables
vCofs = Abc_NtkBddCofactors( dd, (DdNode *)pNode->pData, nLutSize );
vUniq = Vec_PtrDup( vCofs );
Vec_PtrUniqify( vUniq, (int (*)(const void *, const void *))Vec_PtrSortCompare );
// only perform decomposition with it is support reduring with two less vars
if( Vec_PtrSize(vUniq) > (1 << (nLutSize-2)) )
{
Vec_PtrFree( vCofs );
vCofs = Abc_NtkBddCofactors( dd, (DdNode *)pNode->pData, 2 );
if ( fVerbose )
printf( "Decomposing %d-input node %d using cofactoring with %d cofactors.\n",
Abc_ObjFaninNum(pNode), Abc_ObjId(pNode), Vec_PtrSize(vCofs) );
// implement the cofactors
pCofs[0] = Abc_ObjFanin(pNode, 0)->pCopy;
pCofs[1] = Abc_ObjFanin(pNode, 1)->pCopy;
Vec_PtrForEachEntry( DdNode *, vCofs, bCof, i )
pCofs[2+i] = Abc_NtkCreateCofLut( pNtkNew, dd, bCof, pNode, 2 );
if ( nLutSize == 4 )
pNodeNew = Abc_NtkBddMux412( pNtkNew, pCofs );
else if ( nLutSize == 5 )
pNodeNew = Abc_NtkBddMux412a( pNtkNew, pCofs );
else if ( nLutSize == 6 )
pNodeNew = Abc_NtkBddMux411( pNtkNew, pCofs );
else assert( 0 );
}
// alternative decompose using MUX-decomposition
else
{
if ( fVerbose )
printf( "Decomposing %d-input node %d using Curtis with %d unique columns.\n",
Abc_ObjFaninNum(pNode), Abc_ObjId(pNode), Vec_PtrSize(vUniq) );
pNodeNew = Abc_NtkBddCurtis( pNtkNew, pNode, vCofs, vUniq );
}
Vec_PtrFree( vCofs );
Vec_PtrFree( vUniq );
return pNodeNew;
}
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Abc_NtkLutminConstruct( Abc_Ntk_t * pNtkClp, Abc_Ntk_t * pNtkDec, int nLutSize, int fVerbose )
{
Vec_Ptr_t * vNodes;
Abc_Obj_t * pNode, * pFanin;
int i, k;
vNodes = Abc_NtkDfs( pNtkClp, 0 );
Vec_PtrForEachEntry( Abc_Obj_t *, vNodes, pNode, i )
{
if ( Abc_ObjFaninNum(pNode) <= nLutSize )
{
pNode->pCopy = Abc_NtkDupObj( pNtkDec, pNode, 0 );
Abc_ObjForEachFanin( pNode, pFanin, k )
Abc_ObjAddFanin( pNode->pCopy, pFanin->pCopy );
}
else
pNode->pCopy = Abc_NtkBddDecompose( pNtkDec, pNode, nLutSize, fVerbose );
}
Vec_PtrFree( vNodes );
}
/**Function*************************************************************
Synopsis []
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Ntk_t * Abc_NtkLutminInt( Abc_Ntk_t * pNtk, int nLutSize, int fVerbose )
{
extern void Abc_NtkBddReorder( Abc_Ntk_t * pNtk, int fVerbose );
Abc_Ntk_t * pNtkDec;
// minimize BDDs
// Abc_NtkBddReorder( pNtk, fVerbose );
Abc_NtkBddReorder( pNtk, 0 );
// decompose one output at a time
pNtkDec = Abc_NtkStartFrom( pNtk, ABC_NTK_LOGIC, ABC_FUNC_BDD );
// make sure the new manager has enough inputs
Cudd_bddIthVar( (DdManager *)pNtkDec->pManFunc, Abc_NtkGetFaninMax(pNtk) );
// put the results into the new network (save new CO drivers in old CO drivers)
Abc_NtkLutminConstruct( pNtk, pNtkDec, nLutSize, fVerbose );
// finalize the new network
Abc_NtkFinalize( pNtk, pNtkDec );
// make the network minimum base
Abc_NtkMinimumBase( pNtkDec );
return pNtkDec;
}
/**Function*************************************************************
Synopsis [Performs minimum-LUT decomposition of the network.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Abc_Ntk_t * Abc_NtkLutmin( Abc_Ntk_t * pNtkInit, int nLutSize, int fVerbose )
{
extern int Abc_NtkFraigSweep( Abc_Ntk_t * pNtk, int fUseInv, int fExdc, int fVerbose, int fVeryVerbose );
Abc_Ntk_t * pNtkNew, * pTemp;
int i;
if ( nLutSize < 4 )
{
printf( "The LUT count (%d) should be at least 4.\n", nLutSize );
return NULL;
}
if ( nLutSize > 6 )
{
printf( "The LUT count (%d) should not exceed 6.\n", nLutSize );
return NULL;
}
// create internal representation
if ( Abc_NtkIsStrash(pNtkInit) )
pNtkNew = Abc_NtkDup( pNtkInit );
else
pNtkNew = Abc_NtkStrash( pNtkInit, 0, 1, 0 );
// collapse the network
pNtkNew = Abc_NtkCollapse( pTemp = pNtkNew, 10000, 0, 1, 0, 0, 0 );
Abc_NtkDelete( pTemp );
if ( pNtkNew == NULL )
return NULL;
// convert it to BDD
if ( !Abc_NtkIsBddLogic(pNtkNew) )
Abc_NtkToBdd( pNtkNew );
// iterate decomposition
for ( i = 0; Abc_NtkGetFaninMax(pNtkNew) > nLutSize; i++ )
{
if ( fVerbose )
printf( "*** Iteration %d:\n", i+1 );
if ( fVerbose )
printf( "Decomposing network with %d nodes and %d max fanin count for K = %d.\n",
Abc_NtkNodeNum(pNtkNew), Abc_NtkGetFaninMax(pNtkNew), nLutSize );
pNtkNew = Abc_NtkLutminInt( pTemp = pNtkNew, nLutSize, fVerbose );
Abc_NtkDelete( pTemp );
}
// fix the problem with complemented and duplicated CO edges
Abc_NtkLogicMakeSimpleCos( pNtkNew, 0 );
// merge functionally equivalent nodes
Abc_NtkFraigSweep( pNtkNew, 1, 0, 0, 0 );
// make sure everything is okay
if ( !Abc_NtkCheck( pNtkNew ) )
{
printf( "Abc_NtkLutmin: The network check has failed.\n" );
return 0;
}
return pNtkNew;
}
#else
Abc_Ntk_t * Abc_NtkLutmin( Abc_Ntk_t * pNtkInit, int nLutSize, int fVerbose ) { return NULL; }
#endif
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
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