Added command 'addbuffs' to create balanced CI/CO paths.

src/base/abc/abcUtil.c

@@ -2001,9 +2001,66 @@ void Abc_NtkPrintCiLevels( Abc_Ntk_t * pNtk )
     Abc_NtkForEachCi( pNtk, pObj, i )
         printf( "%c=%d ", 'a'+i, pObj->Level );
     printf( "\n" );
+}
+
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
 
+***********************************************************************/
+Abc_Obj_t * Abc_NtkAddBuffsOne( Vec_Ptr_t * vBuffs, Abc_Obj_t * pFanin, int Level, int nLevelMax )
+{
+    Abc_Obj_t * pBuffer;
+    assert( Level - 1 >= Abc_ObjLevel(pFanin) );
+    pBuffer = (Abc_Obj_t *)Vec_PtrEntry( vBuffs, Abc_ObjId(pFanin) * nLevelMax + Level );
+    if ( pBuffer == NULL )
+    {
+        if ( Level - 1 == Abc_ObjLevel(pFanin) )
+            pBuffer = pFanin;
+        else
+            pBuffer = Abc_NtkAddBuffsOne( vBuffs, pFanin, Level - 1, nLevelMax );
+        pBuffer = Abc_NtkCreateNodeBuf( Abc_ObjNtk(pFanin), pBuffer ); 
+        Vec_PtrWriteEntry( vBuffs, Abc_ObjId(pFanin) * nLevelMax + Level, pBuffer );
+    }
+    return pBuffer;
+}
+Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtkInit, int fVerbose )
+{
+    Vec_Ptr_t * vBuffs;
+    Abc_Ntk_t * pNtk = Abc_NtkDup( pNtkInit );
+    Abc_Obj_t * pObj, * pFanin, * pBuffer;
+    int i, k, nLevelMax = Abc_NtkLevel( pNtk );
+    Abc_NtkForEachCo( pNtk, pObj, i )
+        pObj->Level = nLevelMax + 1;
+    vBuffs = Vec_PtrStart( Abc_NtkObjNumMax(pNtk) * nLevelMax );
+    Abc_NtkForEachObj( pNtk, pObj, i )
+    {
+        if ( i == Vec_PtrSize(vBuffs) / nLevelMax )
+            break;
+        if ( !Abc_ObjIsNode(pObj) && !Abc_ObjIsCo(pObj) )
+            continue;
+        Abc_ObjForEachFanin( pObj, pFanin, k )
+        {
+            assert( Abc_ObjLevel(pObj) - 1 >= Abc_ObjLevel(pFanin) );
+            if ( Abc_ObjLevel(pObj) - 1 == Abc_ObjLevel(pFanin) )
+                continue;
+            pBuffer = Abc_NtkAddBuffsOne( vBuffs, pFanin, Abc_ObjLevel(pObj) - 1, nLevelMax );
+            Abc_ObjPatchFanin( pObj, pFanin, pBuffer );
+        }
+    }
+    Vec_PtrFree( vBuffs );
+    Abc_NtkForEachCo( pNtk, pObj, i )
+        pObj->Level = 0;
+    return pNtk;
 }
 
+
 ////////////////////////////////////////////////////////////////////////
 ///                       END OF FILE                                ///
 ////////////////////////////////////////////////////////////////////////

src/base/abci/abc.c

@@ -106,6 +106,7 @@ static int Abc_CommandMfs                    ( Abc_Frame_t * pAbc, int argc, cha
 static int Abc_CommandTrace                  ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int Abc_CommandSpeedup                ( Abc_Frame_t * pAbc, int argc, char ** argv );
 static int Abc_CommandPowerdown              ( Abc_Frame_t * pAbc, int argc, char ** argv );
+static int Abc_CommandAddBuffs               ( Abc_Frame_t * pAbc, int argc, char ** argv );
 //static int Abc_CommandMerge                  ( Abc_Frame_t * pAbc, int argc, char ** argv );
 
 static int Abc_CommandRewrite                ( Abc_Frame_t * pAbc, int argc, char ** argv );
@@ -550,6 +551,7 @@ void Abc_Init( Abc_Frame_t * pAbc )
     Cmd_CommandAdd( pAbc, "Synthesis",    "trace",         Abc_CommandTrace,            0 );
     Cmd_CommandAdd( pAbc, "Synthesis",    "speedup",       Abc_CommandSpeedup,          1 );
     Cmd_CommandAdd( pAbc, "Synthesis",    "powerdown",     Abc_CommandPowerdown,        1 );
+    Cmd_CommandAdd( pAbc, "Synthesis",    "addbuffs",      Abc_CommandAddBuffs,         1 );
 //    Cmd_CommandAdd( pAbc, "Synthesis",    "merge",         Abc_CommandMerge,            1 );
 
     Cmd_CommandAdd( pAbc, "Synthesis",    "rewrite",       Abc_CommandRewrite,          1 );
@@ -4526,6 +4528,70 @@ usage:
     return 1;
 } 
 
+/**Function*************************************************************
+
+  Synopsis    []
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_CommandAddBuffs( Abc_Frame_t * pAbc, int argc, char ** argv )
+{
+    extern Abc_Ntk_t * Abc_NtkAddBuffs( Abc_Ntk_t * pNtk, int fVerbose );
+    Abc_Ntk_t * pNtk = Abc_FrameReadNtk(pAbc);
+    Abc_Ntk_t * pNtkRes;
+    int c, fVerbose;
+
+    fVerbose = 0;
+    Extra_UtilGetoptReset();
+    while ( ( c = Extra_UtilGetopt( argc, argv, "vh" ) ) != EOF )
+    {
+        switch ( c )
+        {
+        case 'v':
+            fVerbose ^= 1;
+            break;
+        case 'h':
+            goto usage;
+        default:
+            goto usage;
+        }
+    }
+
+    if ( pNtk == NULL )
+    {
+        Abc_Print( -1, "Empty network.\n" );
+        return 1;
+    }
+    if ( !Abc_NtkIsLogic(pNtk) )
+    {
+        Abc_Print( -1, "This command can only be applied to a logic network.\n" );
+        return 1;
+    }
+
+    // modify the current network
+    pNtkRes = Abc_NtkAddBuffs( pNtk, fVerbose );
+    if ( pNtkRes == NULL )
+    {
+        Abc_Print( -1, "The command has failed.\n" );
+        return 1;
+    }
+    // replace the current network
+    Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
+    return 0;
+
+usage:
+    Abc_Print( -2, "usage: addbuffs [-vh]\n" );
+    Abc_Print( -2, "\t           adds buffers to create balanced CI/CO paths\n" );
+    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;
+} 
+
 #if 0
 /**Function*************************************************************