Added buffering based on combinational merging.

1 files changed, 219 insertions, 0 deletions

diff --git a/src/map/scl/sclBuff.c b/src/map/scl/sclBuff.c
new file mode 100644
index 00000000..d435ae92
--- /dev/null
+++ b/src/map/scl/sclBuff.c
@@ -0,0 +1,219 @@
+/**CFile****************************************************************
+
+  FileName    [sclBuff.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  Synopsis    [Standard-cell library representation.]
+
+  Author      [Alan Mishchenko, Niklas Een]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - August 24, 2012.]
+
+  Revision    [$Id: sclBuff.c,v 1.0 2012/08/24 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "base/abc/abc.h"
+#include "map/mio/mio.h"
+#include "sclInt.h"
+
+ABC_NAMESPACE_IMPL_START
+
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Make sure the network has no dangling nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_SclCheckNtk( Abc_Ntk_t * p, int fVerbose )
+{
+    Abc_Obj_t * pObj, * pFanin;
+    int i, k, fFlag = 0;
+    Abc_NtkIncrementTravId( p );        
+    Abc_NtkForEachCi( p, pObj, i )
+        Abc_NodeSetTravIdCurrent( pObj );
+    Abc_NtkForEachNode( p, pObj, i )
+    {
+        Abc_ObjForEachFanin( pObj, pFanin, k )
+            if ( !Abc_NodeIsTravIdCurrent( pFanin ) )
+                printf( "obj %d and its fanin %d are not in the topo order\n", Abc_ObjId(pObj), Abc_ObjId(pFanin) ), fFlag = 1;
+        Abc_NodeSetTravIdCurrent( pObj );
+        if ( Abc_ObjFanoutNum(pObj) == 0 )
+            printf( "node %d has no fanout\n", Abc_ObjId(pObj) ), fFlag = 1;
+    }
+    if ( !fFlag && fVerbose )
+        printf( "The network is in topo order and no dangling nodes.\n" );
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Make sure the network has no dangling nodes.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_SclCheckNtk2( Abc_Ntk_t * p )
+{
+    Abc_Obj_t * pObj, * pFanout;
+    int i, k, fFlag = 0;
+    Abc_NtkStartReverseLevels( p, 0 );
+    Abc_NtkForEachNode( p, pObj, i )
+    {
+        if ( Abc_ObjFanoutNum(pObj) <= 3 )
+            continue;
+        printf( "Node %5d (%2d) : fans = %3d  ", i, Abc_ObjLevel(pObj), Abc_ObjFanoutNum(pObj) );
+        Abc_ObjForEachFanout( pObj, pFanout, k )
+            printf( "%d ", Abc_ObjReverseLevel(pFanout) );
+        printf( "\n" );
+    }
+    return 1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Performs buffering of the mapped network.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NodeCompareLevels( Abc_Obj_t ** pp1, Abc_Obj_t ** pp2 )
+{
+    int Diff = Abc_ObjLevel(*pp1) - Abc_ObjLevel(*pp2);
+    if ( Diff < 0 )
+        return -1;
+    if ( Diff > 0 ) 
+        return 1;
+    Diff = (*pp1)->Id - (*pp2)->Id;
+    if ( Diff < 0 )
+        return -1;
+    if ( Diff > 0 ) 
+        return 1;
+    return 0; 
+}
+int Abc_SclComputeReverseLevel( Abc_Obj_t * pObj )
+{
+    Abc_Obj_t * pFanout;
+    int i, Level = 0;
+    Abc_ObjForEachFanout( pObj, pFanout, i )
+        Level = Abc_MaxInt( Level, pFanout->Level );
+    return Level + 1;
+}
+Abc_Obj_t * Abc_SclPerformBufferingOne( Abc_Obj_t * pObj, int Degree, int fVerbose )
+{
+    Vec_Ptr_t * vFanouts;
+    Abc_Obj_t * pBuffer, * pFanout;
+    int i, Degree0 = Degree;
+    assert( Abc_ObjFanoutNum(pObj) > Degree );
+    // collect fanouts and sort by reverse level
+    vFanouts = Vec_PtrAlloc( Abc_ObjFanoutNum(pObj) );
+    Abc_NodeCollectFanouts( pObj, vFanouts );
+    Vec_PtrSort( vFanouts, Abc_NodeCompareLevels );
+    // select the first Degree fanouts
+    pBuffer = Abc_NtkCreateNodeBuf( pObj->pNtk, NULL );
+    // check if it is possible to not increase level
+    if ( Vec_PtrSize(vFanouts) < 2 * Degree )
+    {
+        Abc_Obj_t * pFanPrev = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Vec_PtrSize(vFanouts)-1-Degree);
+        Abc_Obj_t * pFanThis = (Abc_Obj_t *)Vec_PtrEntry(vFanouts, Degree-1);
+        Abc_Obj_t * pFanLast = (Abc_Obj_t *)Vec_PtrEntryLast(vFanouts);
+        if ( Abc_ObjLevel(pFanThis) == Abc_ObjLevel(pFanLast) &&
+             Abc_ObjLevel(pFanPrev) <  Abc_ObjLevel(pFanThis) )
+        {
+            // find the first one whose level is the same as last
+            Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
+                if ( Abc_ObjLevel(pFanout) == Abc_ObjLevel(pFanLast) )
+                    break;
+            assert( i < Vec_PtrSize(vFanouts) );
+            if ( i > 1 )
+                Degree = i;
+        }
+        // make the last two more well-balanced
+        if ( Degree == Degree0 && Degree > Vec_PtrSize(vFanouts) - Degree )
+            Degree = Vec_PtrSize(vFanouts)/2 + (Vec_PtrSize(vFanouts) & 1);
+        assert( Degree <= Degree0 );
+    }
+    // select fanouts
+    Vec_PtrForEachEntryStop( Abc_Obj_t *, vFanouts, pFanout, i, Degree )
+        Abc_ObjPatchFanin( pFanout, pObj, pBuffer );
+    if ( fVerbose )
+    {
+        printf( "%5d : ", Abc_ObjId(pObj) );
+        Vec_PtrForEachEntry( Abc_Obj_t *, vFanouts, pFanout, i )
+            printf( "%d%s ", Abc_ObjLevel(pFanout), i == Degree-1 ? "  " : "" );
+        printf( "\n" );
+    }
+    Vec_PtrFree( vFanouts );
+    Abc_ObjAddFanin( pBuffer, pObj );
+    pBuffer->Level = Abc_SclComputeReverseLevel( pBuffer );
+    return pBuffer;
+}
+void Abc_SclPerformBuffering_rec( Abc_Obj_t * pObj, int Degree, int fVerbose )
+{
+    Abc_Obj_t * pFanout;
+    int i;
+    if ( Abc_NodeIsTravIdCurrent( pObj ) )
+        return;
+    Abc_NodeSetTravIdCurrent( pObj );
+    pObj->Level = 0;
+    if ( Abc_ObjIsCo(pObj) )
+        return;
+    assert( Abc_ObjIsCi(pObj) || Abc_ObjIsNode(pObj) );
+    // buffer fanouts and collect reverse levels
+    Abc_ObjForEachFanout( pObj, pFanout, i )
+        Abc_SclPerformBuffering_rec( pFanout, Degree, fVerbose );
+    // perform buffering as long as needed
+    while ( Abc_ObjFanoutNum(pObj) > Degree )
+        Abc_SclPerformBufferingOne( pObj, Degree, fVerbose );
+    // compute the new level of the node
+    pObj->Level = Abc_SclComputeReverseLevel( pObj );
+}
+Abc_Ntk_t * Abc_SclPerformBuffering( Abc_Ntk_t * p, int Degree, int fVerbose )
+{
+    Abc_Ntk_t * pNew;
+    Abc_Obj_t * pObj;
+    int i;
+    assert( Abc_NtkHasMapping(p) );
+    Abc_NtkIncrementTravId( p );        
+    Abc_NtkForEachCi( p, pObj, i )
+        Abc_SclPerformBuffering_rec( pObj, Degree, fVerbose );
+    Abc_NtkLevel( p );
+    // duplication in topo order
+    pNew = Abc_NtkDupDfs( p );
+    Abc_SclCheckNtk( pNew, fVerbose );
+//    Abc_NtkDelete( pNew );
+    return pNew;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
+ABC_NAMESPACE_IMPL_END
+