Adding reverse order to 'addbuffs'.

src/base/abc/abcUtil.c

@@ -2030,7 +2030,7 @@ Abc_Obj_t * Abc_NtkAddBuffsOne( Vec_Ptr_t * vBuffs, Abc_Obj_t * pFanin, int Leve
     }
     return pBuffer;
 }
-Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtkInit, int fVerbose )
+Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtkInit, int fReverse, int fVerbose )
 {
     Vec_Ptr_t * vBuffs;
     Abc_Ntk_t * pNtk = Abc_NtkDup( pNtkInit );
@@ -2038,6 +2038,21 @@ Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtkInit, int fVerbose )
     int i, k, nLevelMax = Abc_NtkLevel( pNtk );
     Abc_NtkForEachCo( pNtk, pObj, i )
         pObj->Level = nLevelMax + 1;
+    if ( fReverse )
+    {
+        Vec_Ptr_t * vNodes = Abc_NtkDfs( pNtk, 1 );
+        assert( nLevelMax < (1<<18) );
+        Vec_PtrForEachEntryReverse( Abc_Obj_t *, vNodes, pObj, i )
+        {
+            pObj->Level = (1<<18);
+            Abc_ObjForEachFanout( pObj, pFanin, k )
+                pObj->Level = Abc_MinInt( pFanin->Level - 1, pObj->Level );
+            assert( pObj->Level > 0 );
+        }
+        Vec_PtrFree( vNodes );
+        Abc_NtkForEachCi( pNtk, pObj, i )
+            pObj->Level = 0;
+    }
     vBuffs = Vec_PtrStart( Abc_NtkObjNumMax(pNtk) * (nLevelMax + 1) );
     Abc_NtkForEachObj( pNtk, pObj, i )
     {

src/base/abci/abc.c

@@ -4550,17 +4550,22 @@ usage:
 ***********************************************************************/
 int Abc_CommandAddBuffs( Abc_Frame_t * pAbc, int argc, char ** argv )
 {
-    extern Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtk, int fVerbose );
+    extern Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtk, int fReverse, int fVerbose );
     Abc_Ntk_t * pNtk = Abc_FrameReadNtk(pAbc);
     Abc_Ntk_t * pNtkRes;
     int c, fVerbose;
+    int fReverse;
 
+    fReverse = 0;
     fVerbose = 0;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "vh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "rvh" ) ) != EOF )
     {
         switch ( c )
         {
+        case 'r':
+            fReverse ^= 1;
+            break;
         case 'v':
             fVerbose ^= 1;
             break;
@@ -4583,7 +4588,7 @@ int Abc_CommandAddBuffs( Abc_Frame_t * pAbc, int argc, char ** argv )
     }
 
     // modify the current network
-    pNtkRes = Abc_NtkAddBuffs( pNtk, fVerbose );
+    pNtkRes = Abc_NtkAddBuffs( pNtk, fReverse, fVerbose );
     if ( pNtkRes == NULL )
     {
         Abc_Print( -1, "The command has failed.\n" );
@@ -4594,8 +4599,9 @@ int Abc_CommandAddBuffs( Abc_Frame_t * pAbc, int argc, char ** argv )
     return 0;
 
 usage:
-    Abc_Print( -2, "usage: addbuffs [-vh]\n" );
+    Abc_Print( -2, "usage: addbuffs [-rvh]\n" );
     Abc_Print( -2, "\t           adds buffers to create balanced CI/CO paths\n" );
+    Abc_Print( -2, "\t-r       : toggle reversing the levelized order [default = %s]\n", fReverse? "yes": "no" );
     Abc_Print( -2, "\t-v       : toggle printing optimization summary [default = %s]\n", fVerbose? "yes": "no" );
     Abc_Print( -2, "\t-h       : print the command usage\n");
     return 1;