Extending BLIF parser/write to hangle multi-output cells.

15 files changed, 289 insertions, 136 deletions

diff --git a/src/base/abc/abcUtil.c b/src/base/abc/abcUtil.c
index 5a41b109..2ad32dba 100644
--- a/src/base/abc/abcUtil.c
+++ b/src/base/abc/abcUtil.c
@@ -371,6 +371,9 @@ double Abc_NtkGetMappedArea( Abc_Ntk_t * pNtk )
             continue;
         }
         TotalArea += Mio_GateReadArea( (Mio_Gate_t *)pNode->pData );
+        // assuming that twin gates follow each other
+        if ( Mio_GateReadTwin(((Mio_Gate_t *)pNode->pData)) != NULL )
+            i++;
     }
     return TotalArea;
 }
diff --git a/src/base/abci/abcDar.c b/src/base/abci/abcDar.c
index 60911e59..6072a9db 100644
--- a/src/base/abci/abcDar.c
+++ b/src/base/abci/abcDar.c
@@ -3926,7 +3926,7 @@ Abc_Ntk_t * Amap_ManProduceNetwork( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMapping )
     int i, k, iPis, iPos, nDupGates;
     // make sure gates exist in the current library
     Vec_PtrForEachEntry( Amap_Out_t *, vMapping, pRes, i )
-        if ( pRes->pName && Mio_LibraryReadGateByName( pLib, pRes->pName ) == NULL )
+        if ( pRes->pName && Mio_LibraryReadGateByName( pLib, pRes->pName, NULL ) == NULL )
         {
             Abc_Print( 1, "Current library does not contain gate \"%s\".\n", pRes->pName );
             return NULL;
@@ -3945,7 +3945,7 @@ Abc_Ntk_t * Amap_ManProduceNetwork( Abc_Ntk_t * pNtk, Vec_Ptr_t * vMapping )
         else
         {
             pNodeNew = Abc_NtkCreateNode( pNtkNew );
-            pNodeNew->pData = Mio_LibraryReadGateByName( pLib, pRes->pName );
+            pNodeNew->pData = Mio_LibraryReadGateByName( pLib, pRes->pName, NULL );
         }
         for ( k = 0; k < pRes->nFans; k++ )
         {
diff --git a/src/base/abci/abcPrint.c b/src/base/abci/abcPrint.c
index 3244a196..5f151b49 100644
--- a/src/base/abci/abcPrint.c
+++ b/src/base/abci/abcPrint.c
@@ -1013,7 +1013,7 @@ void Abc_NtkPrintGates( Abc_Ntk_t * pNtk, int fUseLibrary )
 
         // clean value of all gates
         nGates = Mio_LibraryReadGateNum( (Mio_Library_t *)pNtk->pManFunc );
-        ppGates = Mio_LibraryReadGatesByName( (Mio_Library_t *)pNtk->pManFunc );
+        ppGates = Mio_LibraryReadGateArray( (Mio_Library_t *)pNtk->pManFunc );
         for ( i = 0; i < nGates; i++ )
             Mio_GateSetValue( ppGates[i], 0 );
 
@@ -1024,6 +1024,9 @@ void Abc_NtkPrintGates( Abc_Ntk_t * pNtk, int fUseLibrary )
             if ( i == 0 ) continue;
             Mio_GateSetValue( (Mio_Gate_t *)pObj->pData, 1 + Mio_GateReadValue((Mio_Gate_t *)pObj->pData) );
             CounterTotal++;
+            // assuming that twin gates follow each other
+            if ( Mio_GateReadTwin(((Mio_Gate_t *)pObj->pData)) != NULL )
+                i++;
         }
 
         // determine the longest gate name
diff --git a/src/base/io/ioReadBlif.c b/src/base/io/ioReadBlif.c
index 592bee4a..74b2927d 100644
--- a/src/base/io/ioReadBlif.c
+++ b/src/base/io/ioReadBlif.c
@@ -525,14 +525,22 @@ int Io_ReadBlifNetworkNames( Io_ReadBlif_t * p, Vec_Ptr_t ** pvTokens )
   SeeAlso     []
 
 ***********************************************************************/
-int Io_ReadBlifReorderFormalNames( Vec_Ptr_t * vTokens, Mio_Gate_t * pGate )
+int Io_ReadBlifReorderFormalNames( Vec_Ptr_t * vTokens, Mio_Gate_t * pGate, Mio_Gate_t * pTwin )
 {
     Mio_Pin_t * pGatePin;
     char * pName, * pNamePin;
     int i, k, nSize, Length;
     nSize = Vec_PtrSize(vTokens);
-    if ( nSize - 3 != Mio_GateReadInputs(pGate) )
-        return 0;
+    if ( pTwin == NULL )
+    {
+        if ( nSize - 3 != Mio_GateReadInputs(pGate) )
+            return 0;
+    }
+    else
+    {
+        if ( nSize - 3 != Mio_GateReadInputs(pGate) && nSize - 4 != Mio_GateReadInputs(pGate) )
+            return 0;
+    }
     // check if the names are in order
     for ( pGatePin = Mio_GateReadPins(pGate), i = 0; pGatePin; pGatePin = Mio_PinReadNext(pGatePin), i++ )
     {
@@ -543,12 +551,26 @@ int Io_ReadBlifReorderFormalNames( Vec_Ptr_t * vTokens, Mio_Gate_t * pGate )
             continue;
         break;
     }
-    if ( i == nSize - 3 )
-        return 1;
-    // reorder the pins
-    for ( pGatePin = Mio_GateReadPins(pGate), i = 0; pGatePin; pGatePin = Mio_PinReadNext(pGatePin), i++ )
+    if ( pTwin == NULL )
     {
-        pNamePin = Mio_PinReadName(pGatePin);
+        if ( i == Mio_GateReadInputs(pGate) )
+            return 1;
+        // reorder the pins
+        for ( pGatePin = Mio_GateReadPins(pGate), i = 0; pGatePin; pGatePin = Mio_PinReadNext(pGatePin), i++ )
+        {
+            pNamePin = Mio_PinReadName(pGatePin);
+            Length = strlen(pNamePin);
+            for ( k = 2; k < nSize; k++ )
+            {
+                pName = (char *)Vec_PtrEntry(vTokens, k);
+                if ( !strncmp( pNamePin, pName, Length ) && pName[Length] == '=' )
+                {
+                    Vec_PtrPush( vTokens, pName );
+                    break;
+                }
+            }
+        }
+        pNamePin = Mio_GateReadOutName(pGate);
         Length = strlen(pNamePin);
         for ( k = 2; k < nSize; k++ )
         {
@@ -559,23 +581,55 @@ int Io_ReadBlifReorderFormalNames( Vec_Ptr_t * vTokens, Mio_Gate_t * pGate )
                 break;
             }
         }
+        if ( Vec_PtrSize(vTokens) - nSize != nSize - 2 )
+            return 0;
+        Vec_PtrForEachEntryStart( char *, vTokens, pName, k, nSize )
+            Vec_PtrWriteEntry( vTokens, k - nSize + 2, pName );
+        Vec_PtrShrink( vTokens, nSize );
     }
-    pNamePin = Mio_GateReadOutName(pGate);
-    Length = strlen(pNamePin);
-    for ( k = 2; k < nSize; k++ )
+    else
     {
-        pName = (char *)Vec_PtrEntry(vTokens, k);
-        if ( !strncmp( pNamePin, pName, Length ) && pName[Length] == '=' )
+        if ( i != Mio_GateReadInputs(pGate) ) // expect the correct order of input pins in the network with twin gates
+            return 0;
+        // check the last two entries
+        if ( nSize - 3 == Mio_GateReadInputs(pGate) ) // only one output is available
         {
-            Vec_PtrPush( vTokens, pName );
-            break;
+            pNamePin = Mio_GateReadOutName(pGate);
+            Length = strlen(pNamePin);
+            pName = (char *)Vec_PtrEntry(vTokens, nSize - 1);
+            if ( !strncmp( pNamePin, pName, Length ) && pName[Length] == '=' ) // the last entry is pGate
+            {
+                Vec_PtrPush( vTokens, NULL );
+                return 1;
+            }
+            pNamePin = Mio_GateReadOutName(pTwin);
+            Length = strlen(pNamePin);
+            pName = (char *)Vec_PtrEntry(vTokens, nSize - 1);
+            if ( !strncmp( pNamePin, pName, Length ) && pName[Length] == '=' ) // the last entry is pTwin
+            {
+                pName = Vec_PtrPop( vTokens );
+                Vec_PtrPush( vTokens, NULL );
+                Vec_PtrPush( vTokens, pName );
+                return 1;
+            }
+            return 0;
         }
+        if ( nSize - 4 == Mio_GateReadInputs(pGate) ) // two outputs are available
+        {
+            pNamePin = Mio_GateReadOutName(pGate);
+            Length = strlen(pNamePin);
+            pName = (char *)Vec_PtrEntry(vTokens, nSize - 2);
+            if ( !(!strncmp( pNamePin, pName, Length ) && pName[Length] == '=') )
+                return 0;
+            pNamePin = Mio_GateReadOutName(pTwin);
+            Length = strlen(pNamePin);
+            pName = (char *)Vec_PtrEntry(vTokens, nSize - 1);
+            if ( !(!strncmp( pNamePin, pName, Length ) && pName[Length] == '=') )
+                return 0;
+            return 1;
+        }
+        assert( 0 );
     }
-    if ( Vec_PtrSize(vTokens) - nSize != nSize - 2 )
-        return 0;
-    Vec_PtrForEachEntryStart( char *, vTokens, pName, k, nSize )
-        Vec_PtrWriteEntry( vTokens, k - nSize + 2, pName );
-    Vec_PtrShrink( vTokens, nSize );
     return 1;
 }
 
@@ -618,7 +672,7 @@ int Io_ReadBlifNetworkGate( Io_ReadBlif_t * p, Vec_Ptr_t * vTokens )
     }
 
     // get the gate
-    pGate = Mio_LibraryReadGateByName( pGenlib, (char *)vTokens->pArray[1] );
+    pGate = Mio_LibraryReadGateByName( pGenlib, (char *)vTokens->pArray[1], NULL );
     if ( pGate == NULL )
     {
         p->LineCur = Extra_FileReaderGetLineNumber(p->pReader, 0);
@@ -637,7 +691,7 @@ int Io_ReadBlifNetworkGate( Io_ReadBlif_t * p, Vec_Ptr_t * vTokens )
     }
 
     // reorder the formal inputs to be in the same order as in the gate
-    if ( !Io_ReadBlifReorderFormalNames( vTokens, pGate ) )
+    if ( !Io_ReadBlifReorderFormalNames( vTokens, pGate, Mio_GateReadTwin(pGate) ) )
     {
         p->LineCur = Extra_FileReaderGetLineNumber(p->pReader, 0);
         sprintf( p->sError, "Mismatch in the fanins of gate \"%s\".", (char*)vTokens->pArray[1] );
@@ -660,12 +714,29 @@ int Io_ReadBlifNetworkGate( Io_ReadBlif_t * p, Vec_Ptr_t * vTokens )
     }
 
     // create the node
-    ppNames = (char **)vTokens->pArray + 2;
-    nNames  = vTokens->nSize - 3;
-    pNode   = Io_ReadCreateNode( p->pNtkCur, ppNames[nNames], ppNames, nNames );
-
-    // set the pointer to the functionality of the node
-    Abc_ObjSetData( pNode, pGate );
+    if ( Mio_GateReadTwin(pGate) == NULL )
+    {
+        nNames  = vTokens->nSize - 3;
+        ppNames = (char **)vTokens->pArray + 2;
+        pNode   = Io_ReadCreateNode( p->pNtkCur, ppNames[nNames], ppNames, nNames );
+        Abc_ObjSetData( pNode, pGate );
+    }
+    else
+    {
+        nNames  = vTokens->nSize - 4;
+        ppNames = (char **)vTokens->pArray + 2;
+        assert( ppNames[nNames] != NULL || ppNames[nNames+1] != NULL );
+        if ( ppNames[nNames] )
+        {
+            pNode   = Io_ReadCreateNode( p->pNtkCur, ppNames[nNames], ppNames, nNames );
+            Abc_ObjSetData( pNode, pGate );
+        }
+        if ( ppNames[nNames+1] )
+        {
+            pNode   = Io_ReadCreateNode( p->pNtkCur, ppNames[nNames+1], ppNames, nNames );
+            Abc_ObjSetData( pNode, Mio_GateReadTwin(pGate) );
+        }
+    }
     return 0;
 }
 
diff --git a/src/base/io/ioReadBlifMv.c b/src/base/io/ioReadBlifMv.c
index 57cbb915..bbaad423 100644
--- a/src/base/io/ioReadBlifMv.c
+++ b/src/base/io/ioReadBlifMv.c
@@ -2090,7 +2090,7 @@ static char * Io_ReadBlifCleanName( char * pName )
 ***********************************************************************/
 static int Io_MvParseLineGateBlif( Io_MvMod_t * p, Vec_Ptr_t * vTokens )
 {
-    extern int Io_ReadBlifReorderFormalNames( Vec_Ptr_t * vTokens, Mio_Gate_t * pGate );
+    extern int Io_ReadBlifReorderFormalNames( Vec_Ptr_t * vTokens, Mio_Gate_t * pGate, Mio_Gate_t * pTwin );
     Mio_Library_t * pGenlib; 
     Mio_Gate_t * pGate;
     Abc_Obj_t * pNode;
@@ -2115,7 +2115,7 @@ static int Io_MvParseLineGateBlif( Io_MvMod_t * p, Vec_Ptr_t * vTokens )
     }
 
     // get the gate
-    pGate = Mio_LibraryReadGateByName( pGenlib, (char *)vTokens->pArray[1] );
+    pGate = Mio_LibraryReadGateByName( pGenlib, (char *)vTokens->pArray[1], NULL );
     if ( pGate == NULL )
     {
         sprintf( p->pMan->sError, "Line %d: Cannot find gate \"%s\" in the library.", Io_MvGetLine(p->pMan, pName), (char*)vTokens->pArray[1] );
@@ -2132,7 +2132,7 @@ static int Io_MvParseLineGateBlif( Io_MvMod_t * p, Vec_Ptr_t * vTokens )
     }
 
     // reorder the formal inputs to be in the same order as in the gate
-    if ( !Io_ReadBlifReorderFormalNames( vTokens, pGate ) )
+    if ( !Io_ReadBlifReorderFormalNames( vTokens, pGate, Mio_GateReadTwin(pGate) ) )
     {
         sprintf( p->pMan->sError, "Line %d: Mismatch in the fanins of gate \"%s\".", Io_MvGetLine(p->pMan, pName), (char*)vTokens->pArray[1] );
         return 0;
@@ -2141,6 +2141,8 @@ static int Io_MvParseLineGateBlif( Io_MvMod_t * p, Vec_Ptr_t * vTokens )
     // remove the formal parameter names
     for ( i = 2; i < vTokens->nSize; i++ )
     {
+        if ( vTokens->pArray[i] == NULL )
+            continue;
         vTokens->pArray[i] = Io_ReadBlifCleanName( (char *)vTokens->pArray[i] );
         if ( vTokens->pArray[i] == NULL )
         {
@@ -2150,12 +2152,30 @@ static int Io_MvParseLineGateBlif( Io_MvMod_t * p, Vec_Ptr_t * vTokens )
     }
 
     // create the node
-    ppNames = (char **)vTokens->pArray + 2;
-    nNames  = vTokens->nSize - 3;
-    pNode   = Io_ReadCreateNode( p->pNtk, ppNames[nNames], ppNames, nNames );
+    if ( Mio_GateReadTwin(pGate) == NULL )
+    {
+        nNames  = vTokens->nSize - 3;
+        ppNames = (char **)vTokens->pArray + 2;
+        pNode   = Io_ReadCreateNode( p->pNtk, ppNames[nNames], ppNames, nNames );
+        Abc_ObjSetData( pNode, pGate );
+    }
+    else
+    {
+        nNames  = vTokens->nSize - 4;
+        ppNames = (char **)vTokens->pArray + 2;
+        assert( ppNames[nNames] != NULL || ppNames[nNames+1] != NULL );
+        if ( ppNames[nNames] )
+        {
+            pNode   = Io_ReadCreateNode( p->pNtk, ppNames[nNames], ppNames, nNames );
+            Abc_ObjSetData( pNode, pGate );
+        }
+        if ( ppNames[nNames+1] )
+        {
+            pNode   = Io_ReadCreateNode( p->pNtk, ppNames[nNames+1], ppNames, nNames );
+            Abc_ObjSetData( pNode, Mio_GateReadTwin(pGate) );
+        }
+    }
 
-    // set the pointer to the functionality of the node
-    Abc_ObjSetData( pNode, pGate );
     return 1;
 }
 
diff --git a/src/base/io/ioWriteBlif.c b/src/base/io/ioWriteBlif.c
index 54be8434..a8305d07 100644
--- a/src/base/io/ioWriteBlif.c
+++ b/src/base/io/ioWriteBlif.c
@@ -37,9 +37,8 @@ static void Io_NtkWritePis( FILE * pFile, Abc_Ntk_t * pNtk, int fWriteLatches );
 static void Io_NtkWritePos( FILE * pFile, Abc_Ntk_t * pNtk, int fWriteLatches );
 static void Io_NtkWriteSubckt( FILE * pFile, Abc_Obj_t * pNode );
 static void Io_NtkWriteAsserts( FILE * pFile, Abc_Ntk_t * pNtk );
-static void Io_NtkWriteNodeGate( FILE * pFile, Abc_Obj_t * pNode, int Length );
 static void Io_NtkWriteNodeFanins( FILE * pFile, Abc_Obj_t * pNode );
-static void Io_NtkWriteNode( FILE * pFile, Abc_Obj_t * pNode, int Length );
+static int  Io_NtkWriteNode( FILE * pFile, Abc_Obj_t * pNode, int Length );
 static void Io_NtkWriteLatch( FILE * pFile, Abc_Obj_t * pLatch );
 
 ////////////////////////////////////////////////////////////////////////
@@ -251,7 +250,8 @@ void Io_NtkWriteOne( FILE * pFile, Abc_Ntk_t * pNtk, int fWriteLatches, int fBb2
     Abc_NtkForEachNode( pNtk, pNode, i )
     {
         Extra_ProgressBarUpdate( pProgress, i, NULL );
-        Io_NtkWriteNode( pFile, pNode, Length );
+        if ( Io_NtkWriteNode( pFile, pNode, Length ) ) // skip the next node
+            i++;
     }
     Extra_ProgressBarStop( pProgress );
 }
@@ -462,7 +462,7 @@ void Io_NtkWriteLatch( FILE * pFile, Abc_Obj_t * pLatch )
 
 /**Function*************************************************************
 
-  Synopsis    [Write the node into a file.]
+  Synopsis    [Writes the primary input list.]
 
   Description []
                
@@ -471,24 +471,47 @@ void Io_NtkWriteLatch( FILE * pFile, Abc_Obj_t * pLatch )
   SeeAlso     []
 
 ***********************************************************************/
-void Io_NtkWriteNode( FILE * pFile, Abc_Obj_t * pNode, int Length )
+void Io_NtkWriteNodeFanins( FILE * pFile, Abc_Obj_t * pNode )
 {
-    if ( Abc_NtkHasMapping(pNode->pNtk) )
+    Abc_Obj_t * pNet;
+    int LineLength;
+    int AddedLength;
+    int NameCounter;
+    char * pName;
+    int i;
+
+    LineLength  = 6;
+    NameCounter = 0;
+    Abc_ObjForEachFanin( pNode, pNet, i )
     {
-        // write the .gate line
-        fprintf( pFile, ".gate" );
-        Io_NtkWriteNodeGate( pFile, pNode, Length );
-        fprintf( pFile, "\n" );
+        // get the fanin name
+        pName = Abc_ObjName(pNet);
+        // get the line length after the fanin name is written
+        AddedLength = strlen(pName) + 1;
+        if ( NameCounter && LineLength + AddedLength + 3 > IO_WRITE_LINE_LENGTH )
+        { // write the line extender
+            fprintf( pFile, " \\\n" );
+            // reset the line length
+            LineLength  = 0;
+            NameCounter = 0;
+        }
+        fprintf( pFile, " %s", pName );
+        LineLength += AddedLength;
+        NameCounter++;
     }
-    else
-    {
-        // write the .names line
-        fprintf( pFile, ".names" );
-        Io_NtkWriteNodeFanins( pFile, pNode );
-        fprintf( pFile, "\n" );
-        // write the cubes
-        fprintf( pFile, "%s", (char*)Abc_ObjData(pNode) );
+
+    // get the output name
+    pName = Abc_ObjName(Abc_ObjFanout0(pNode));
+    // get the line length after the output name is written
+    AddedLength = strlen(pName) + 1;
+    if ( NameCounter && LineLength + AddedLength > 75 )
+    { // write the line extender
+        fprintf( pFile, " \\\n" );
+        // reset the line length
+        LineLength  = 0;
+        NameCounter = 0;
     }
+    fprintf( pFile, " %s", pName );
 }
 
 /**Function*************************************************************
@@ -502,10 +525,12 @@ void Io_NtkWriteNode( FILE * pFile, Abc_Obj_t * pNode, int Length )
   SeeAlso     []
 
 ***********************************************************************/
-void Io_NtkWriteNodeGate( FILE * pFile, Abc_Obj_t * pNode, int Length )
+int Io_NtkWriteNodeGate( FILE * pFile, Abc_Obj_t * pNode, int Length )
 {
     Mio_Gate_t * pGate = (Mio_Gate_t *)pNode->pData;
+    Mio_Gate_t * pGate2;
     Mio_Pin_t * pGatePin;
+    Abc_Obj_t * pNode2;
     int i;
     // write the node
     fprintf( pFile, " %-*s ", Length, Mio_GateReadName(pGate) );
@@ -513,11 +538,33 @@ void Io_NtkWriteNodeGate( FILE * pFile, Abc_Obj_t * pNode, int Length )
         fprintf( pFile, "%s=%s ", Mio_PinReadName(pGatePin), Abc_ObjName( Abc_ObjFanin(pNode,i) ) );
     assert ( i == Abc_ObjFaninNum(pNode) );
     fprintf( pFile, "%s=%s", Mio_GateReadOutName(pGate), Abc_ObjName( Abc_ObjFanout0(pNode) ) );
+    if ( Mio_GateReadTwin(pGate) == NULL )
+        return 0;
+    // assuming the twin node is following next
+    if ( (int)Abc_ObjId(pNode) == Abc_NtkObjNumMax(pNode->pNtk) - 1 )
+    {
+        printf( "Warning: Missing second output of gate \"%s\".\n", Mio_GateReadName(pGate) );
+        return 0;
+    }
+    pNode2 = Abc_NtkObj( pNode->pNtk, Abc_ObjId(pNode) + 1 );
+    if ( !Abc_ObjIsNode(pNode2) || Abc_ObjFaninNum(pNode) != Abc_ObjFaninNum(pNode2) )
+    {
+        printf( "Warning: Missing second output of gate \"%s\".\n", Mio_GateReadName(pGate) );
+        return 0;
+    }
+    pGate2 = (Mio_Gate_t *)pNode2->pData;
+    if ( strcmp( Mio_GateReadName(pGate), Mio_GateReadName(pGate2)) )
+    {
+        printf( "Warning: Missing second output of gate \"%s\".\n", Mio_GateReadName(pGate) );
+        return 0;
+    }
+    fprintf( pFile, " %s=%s", Mio_GateReadOutName(pGate2), Abc_ObjName( Abc_ObjFanout0(pNode2) ) );
+    return 1;
 }
 
 /**Function*************************************************************
 
-  Synopsis    [Writes the primary input list.]
+  Synopsis    [Write the node into a file.]
 
   Description []
                
@@ -526,47 +573,26 @@ void Io_NtkWriteNodeGate( FILE * pFile, Abc_Obj_t * pNode, int Length )
   SeeAlso     []
 
 ***********************************************************************/
-void Io_NtkWriteNodeFanins( FILE * pFile, Abc_Obj_t * pNode )
+int Io_NtkWriteNode( FILE * pFile, Abc_Obj_t * pNode, int Length )
 {
-    Abc_Obj_t * pNet;
-    int LineLength;
-    int AddedLength;
-    int NameCounter;
-    char * pName;
-    int i;
-
-    LineLength  = 6;
-    NameCounter = 0;
-    Abc_ObjForEachFanin( pNode, pNet, i )
+    int RetValue = 0;
+    if ( Abc_NtkHasMapping(pNode->pNtk) )
     {
-        // get the fanin name
-        pName = Abc_ObjName(pNet);
-        // get the line length after the fanin name is written
-        AddedLength = strlen(pName) + 1;
-        if ( NameCounter && LineLength + AddedLength + 3 > IO_WRITE_LINE_LENGTH )
-        { // write the line extender
-            fprintf( pFile, " \\\n" );
-            // reset the line length
-            LineLength  = 0;
-            NameCounter = 0;
-        }
-        fprintf( pFile, " %s", pName );
-        LineLength += AddedLength;
-        NameCounter++;
+        // write the .gate line
+        fprintf( pFile, ".gate" );
+        RetValue = Io_NtkWriteNodeGate( pFile, pNode, Length );
+        fprintf( pFile, "\n" );
     }
-
-    // get the output name
-    pName = Abc_ObjName(Abc_ObjFanout0(pNode));
-    // get the line length after the output name is written
-    AddedLength = strlen(pName) + 1;
-    if ( NameCounter && LineLength + AddedLength > 75 )
-    { // write the line extender
-        fprintf( pFile, " \\\n" );
-        // reset the line length
-        LineLength  = 0;
-        NameCounter = 0;
+    else
+    {
+        // write the .names line
+        fprintf( pFile, ".names" );
+        Io_NtkWriteNodeFanins( pFile, pNode );
+        fprintf( pFile, "\n" );
+        // write the cubes
+        fprintf( pFile, "%s", (char*)Abc_ObjData(pNode) );
     }
-    fprintf( pFile, " %s", pName );
+    return RetValue;
 }
 
 /**Function*************************************************************
diff --git a/src/base/ver/verCore.c b/src/base/ver/verCore.c
index 4e131c85..aeea1984 100644
--- a/src/base/ver/verCore.c
+++ b/src/base/ver/verCore.c
@@ -490,7 +490,7 @@ int Ver_ParseModule( Ver_Man_t * pMan )
             RetValue = Ver_ParseInitial( pMan, pNtk );
         else if ( !strcmp( pWord, "endmodule" ) )
             break;
-        else if ( pMan->pDesign->pGenlib && (pGate = Mio_LibraryReadGateByName((Mio_Library_t *)pMan->pDesign->pGenlib, pWord)) ) // current design
+        else if ( pMan->pDesign->pGenlib && (pGate = Mio_LibraryReadGateByName((Mio_Library_t *)pMan->pDesign->pGenlib, pWord, NULL)) ) // current design
             RetValue = Ver_ParseGate( pMan, pNtk, pGate );
 //        else if ( pMan->pDesign->pLibrary && st_lookup(pMan->pDesign->pLibrary->tModules, pWord, (char**)&pNtkTemp) ) // gate library
 //            RetValue = Ver_ParseGate( pMan, pNtkTemp );
@@ -1506,6 +1506,8 @@ int Ver_FindGateInput( Mio_Gate_t * pGate, char * pName )
             return i;
     if ( strcmp(pName, Mio_GateReadOutName(pGate)) == 0 )
         return i;
+    if ( Mio_GateReadTwin(pGate) && strcmp(pName, Mio_GateReadOutName(Mio_GateReadTwin(pGate))) == 0 )
+        return i+1;
     return -1;
 }
 
@@ -1523,7 +1525,7 @@ int Ver_FindGateInput( Mio_Gate_t * pGate, char * pName )
 int Ver_ParseGate( Ver_Man_t * pMan, Abc_Ntk_t * pNtk, Mio_Gate_t * pGate )
 {
     Ver_Stream_t * p = pMan->pReader;
-    Abc_Obj_t * pNetActual, * pNode;
+    Abc_Obj_t * pNetActual, * pNode, * pNode2 = NULL;
     char * pWord, Symbol;
     int Input, i, nFanins = Mio_GateReadInputs(pGate);
 
@@ -1555,7 +1557,11 @@ int Ver_ParseGate( Ver_Man_t * pMan, Abc_Ntk_t * pNtk, Mio_Gate_t * pGate )
     // start the node
     pNode = Abc_NtkCreateNode( pNtk );
     pNode->pData = pGate;
-
+    if ( Mio_GateReadTwin(pGate) )
+    {
+        pNode2 = Abc_NtkCreateNode( pNtk );
+        pNode2->pData = Mio_GateReadTwin(pGate);
+    }
     // parse pairs of formal/actural inputs
     Vec_IntClear( pMan->vPerm );
     while ( 1 )
@@ -1628,9 +1634,15 @@ int Ver_ParseGate( Ver_Man_t * pMan, Abc_Ntk_t * pNtk, Mio_Gate_t * pGate )
         {
             Vec_IntPush( pMan->vPerm, Input );
             Abc_ObjAddFanin( pNode, pNetActual ); // fanin
+            if ( pNode2 )
+                Abc_ObjAddFanin( pNode2, pNetActual ); // fanin
         }
-        else
+        else if ( Input == nFanins )
             Abc_ObjAddFanin( pNetActual, pNode ); // fanout
+        else if ( Input == nFanins + 1 )
+            Abc_ObjAddFanin( pNetActual, pNode2 ); // fanout
+        else
+            assert( 0 );
 
         // check if it is the end of gate
         Ver_ParseSkipComments( pMan );
diff --git a/src/map/mapper/mapperSuper.c b/src/map/mapper/mapperSuper.c
index efcb90ea..bf351a54 100644
--- a/src/map/mapper/mapperSuper.c
+++ b/src/map/mapper/mapperSuper.c
@@ -382,7 +382,7 @@ void Map_LibraryComputeTruth_rec( Map_SuperLib_t * pLib, char * pFormula, unsign
     for ( i = 0; i < nStrings; i++ )
         Map_LibraryComputeTruth_rec( pLib, pStrings[i], uTruthsIn, uTruthsFanins[i] );
     // get the root supergate
-    pMioGate = Mio_LibraryReadGateByName( pLib->pGenlib, pGateName );
+    pMioGate = Mio_LibraryReadGateByName( pLib->pGenlib, pGateName, NULL );
     if ( pMioGate == NULL )
         printf( "A supergate contains gate \"%s\" that is not in \"%s\".\n", pGateName, Mio_LibraryReadName(pLib->pGenlib) ); 
     // derive the functionality of the output of the supergate
diff --git a/src/map/mapper/mapperTree.c b/src/map/mapper/mapperTree.c
index 2244fa26..36ad4920 100644
--- a/src/map/mapper/mapperTree.c
+++ b/src/map/mapper/mapperTree.c
@@ -302,7 +302,7 @@ Map_Super_t * Map_LibraryReadGateTree( Map_SuperLib_t * pLib, char * pBuffer, in
     }
 
     // read the root gate
-    pGate->pRoot = Mio_LibraryReadGateByName( pLib->pGenlib, pTemp );
+    pGate->pRoot = Mio_LibraryReadGateByName( pLib->pGenlib, pTemp, NULL );
     if ( pGate->pRoot == NULL )
     {
         printf( "Cannot read the root gate names %s.\n", pTemp );
diff --git a/src/map/mapper/mapperTree_old.c b/src/map/mapper/mapperTree_old.c
index 1a76b267..eafba376 100644
--- a/src/map/mapper/mapperTree_old.c
+++ b/src/map/mapper/mapperTree_old.c
@@ -299,7 +299,7 @@ Map_Super_t * Map_LibraryReadGateTree( Map_SuperLib_t * pLib, char * pBuffer, in
     }
 
     // read the root gate
-    pGate->pRoot = Mio_LibraryReadGateByName( pLib->pGenlib, pTemp );
+    pGate->pRoot = Mio_LibraryReadGateByName( pLib->pGenlib, pTemp, NULL );
     if ( pGate->pRoot == NULL )
     {
         printf( "Cannot read the root gate names %s.\n", pTemp );
diff --git a/src/map/mio/mio.h b/src/map/mio/mio.h
index 7bccc3a1..3aff8790 100644
--- a/src/map/mio/mio.h
+++ b/src/map/mio/mio.h
@@ -68,8 +68,8 @@ static inline char *    Mio_UtilStrsav( char * s )     { return s ? strcpy(ABC_A
     for ( Pin = Mio_GateReadPins(Gate);                       \
           Pin;                                                \
           Pin = Mio_PinReadNext(Pin) )
-#define Mio_GateForEachPinSafe( Gate, Pin, Pin2 )              \
-    for ( Pin = Mio_GateReadPins(Gate),                        \
+#define Mio_GateForEachPinSafe( Gate, Pin, Pin2 )             \
+    for ( Pin = Mio_GateReadPins(Gate),                       \
           Pin2 = (Pin? Mio_PinReadNext(Pin): NULL);           \
           Pin;                                                \
           Pin = Pin2,                                         \
@@ -83,8 +83,8 @@ static inline char *    Mio_UtilStrsav( char * s )     { return s ? strcpy(ABC_A
 extern char *            Mio_LibraryReadName       ( Mio_Library_t * pLib );
 extern int               Mio_LibraryReadGateNum    ( Mio_Library_t * pLib );
 extern Mio_Gate_t *      Mio_LibraryReadGates      ( Mio_Library_t * pLib );
-extern Mio_Gate_t **     Mio_LibraryReadGatesByName( Mio_Library_t * pLib );
-extern Mio_Gate_t *      Mio_LibraryReadGateByName ( Mio_Library_t * pLib, char * pName );
+extern Mio_Gate_t **     Mio_LibraryReadGateArray  ( Mio_Library_t * pLib );
+extern Mio_Gate_t *      Mio_LibraryReadGateByName ( Mio_Library_t * pLib, char * pName, char * pOutName );
 extern char *            Mio_LibraryReadSopByName  ( Mio_Library_t * pLib, char * pName );    
 extern Mio_Gate_t *      Mio_LibraryReadConst0     ( Mio_Library_t * pLib );
 extern Mio_Gate_t *      Mio_LibraryReadConst1     ( Mio_Library_t * pLib );
@@ -110,6 +110,7 @@ extern char *            Mio_GateReadForm          ( Mio_Gate_t * pGate );
 extern Mio_Pin_t *       Mio_GateReadPins          ( Mio_Gate_t * pGate );      
 extern Mio_Library_t *   Mio_GateReadLib           ( Mio_Gate_t * pGate );      
 extern Mio_Gate_t *      Mio_GateReadNext          ( Mio_Gate_t * pGate );      
+extern Mio_Gate_t *      Mio_GateReadTwin          ( Mio_Gate_t * pGate );      
 extern int               Mio_GateReadInputs        ( Mio_Gate_t * pGate );      
 extern double            Mio_GateReadDelayMax      ( Mio_Gate_t * pGate );      
 extern char *            Mio_GateReadSop           ( Mio_Gate_t * pGate );      
diff --git a/src/map/mio/mioApi.c b/src/map/mio/mioApi.c
index d2357e7d..2fe23c2c 100644
--- a/src/map/mio/mioApi.c
+++ b/src/map/mio/mioApi.c
@@ -40,13 +40,12 @@ ABC_NAMESPACE_IMPL_START
   SeeAlso     []
 
 ***********************************************************************/
-char *            Mio_LibraryReadName          ( Mio_Library_t * pLib )  { return pLib->pName;    }
-int               Mio_LibraryReadGateNum       ( Mio_Library_t * pLib )  { return pLib->nGates;   }
-Mio_Gate_t *      Mio_LibraryReadGates         ( Mio_Library_t * pLib )  { return pLib->pGates;   }
-Mio_Gate_t **     Mio_LibraryReadGatesByName   ( Mio_Library_t * pLib )  { return pLib->ppGatesName;}
-//DdManager *       Mio_LibraryReadDd            ( Mio_Library_t * pLib )  { return pLib->dd;       }
-Mio_Gate_t *      Mio_LibraryReadBuf           ( Mio_Library_t * pLib )  { return pLib->pGateBuf; }
-Mio_Gate_t *      Mio_LibraryReadInv           ( Mio_Library_t * pLib )  { return pLib->pGateInv; }
+char *            Mio_LibraryReadName          ( Mio_Library_t * pLib )  { return pLib->pName;      }
+int               Mio_LibraryReadGateNum       ( Mio_Library_t * pLib )  { return pLib->nGates;     }
+Mio_Gate_t *      Mio_LibraryReadGates         ( Mio_Library_t * pLib )  { return pLib->pGates;     }
+Mio_Gate_t **     Mio_LibraryReadGateArray     ( Mio_Library_t * pLib )  { return pLib->ppGatesName;}
+Mio_Gate_t *      Mio_LibraryReadBuf           ( Mio_Library_t * pLib )  { return pLib->pGateBuf;   }
+Mio_Gate_t *      Mio_LibraryReadInv           ( Mio_Library_t * pLib )  { return pLib->pGateInv;   }
 Mio_Gate_t *      Mio_LibraryReadConst0        ( Mio_Library_t * pLib )  { return pLib->pGate0;     }
 Mio_Gate_t *      Mio_LibraryReadConst1        ( Mio_Library_t * pLib )  { return pLib->pGate1;     }
 Mio_Gate_t *      Mio_LibraryReadNand2         ( Mio_Library_t * pLib )  { return pLib->pGateNand2; }
@@ -97,11 +96,17 @@ int Mio_LibraryReadGateNameMax( Mio_Library_t * pLib )
   SeeAlso     []
 
 ***********************************************************************/
-Mio_Gate_t * Mio_LibraryReadGateByName( Mio_Library_t * pLib, char * pName )      
+Mio_Gate_t * Mio_LibraryReadGateByName( Mio_Library_t * pLib, char * pName, char * pOutName )      
 { 
     Mio_Gate_t * pGate;
-    if ( st_lookup( pLib->tName2Gate, pName, (char **)&pGate ) )
+    if ( !st_lookup( pLib->tName2Gate, pName, (char **)&pGate ) )
+        return NULL;
+    if ( pOutName == NULL )
+        return pGate;
+    if ( !strcmp(pGate->pOutName, pOutName) )
         return pGate;
+    if ( pGate->pTwin && !strcmp(pGate->pTwin->pOutName, pOutName) )
+        return pGate->pTwin;
     return NULL;
 }
 
@@ -142,10 +147,10 @@ char *            Mio_GateReadForm    ( Mio_Gate_t * pGate )            { return
 Mio_Pin_t *       Mio_GateReadPins    ( Mio_Gate_t * pGate )            { return pGate->pPins;     }
 Mio_Library_t *   Mio_GateReadLib     ( Mio_Gate_t * pGate )            { return pGate->pLib;      }
 Mio_Gate_t *      Mio_GateReadNext    ( Mio_Gate_t * pGate )            { return pGate->pNext;     }
+Mio_Gate_t *      Mio_GateReadTwin    ( Mio_Gate_t * pGate )            { return pGate->pTwin;     }
 int               Mio_GateReadInputs  ( Mio_Gate_t * pGate )            { return pGate->nInputs;   }
 double            Mio_GateReadDelayMax( Mio_Gate_t * pGate )            { return pGate->dDelayMax; }
 char *            Mio_GateReadSop     ( Mio_Gate_t * pGate )            { return pGate->pSop;      }
-//DdNode *          Mio_GateReadFunc    ( Mio_Gate_t * pGate )            { return pGate->bFunc;     }
 word              Mio_GateReadTruth   ( Mio_Gate_t * pGate )            { return pGate->nInputs <= 6 ? pGate->uTruth : 0;   }
 word *            Mio_GateReadTruthP  ( Mio_Gate_t * pGate )            { return pGate->nInputs <= 6 ? NULL: pGate->pTruth; }
 int               Mio_GateReadValue   ( Mio_Gate_t * pGate )            { return pGate->Value;     }
diff --git a/src/map/mio/mioRead.c b/src/map/mio/mioRead.c
index 87fb68e2..53ea7d2d 100644
--- a/src/map/mio/mioRead.c
+++ b/src/map/mio/mioRead.c
@@ -233,10 +233,15 @@ int Mio_LibraryReadInternal( Mio_Library_t * pLib, char * pBuffer, int fExtended
                 st_insert( pLib->tName2Gate, pGate->pName, (char *)pGate );
             else
             {
-                Mio_Gate_t * pBase = Mio_LibraryReadGateByName( pLib, pGate->pName );
-                pBase->pTwin = pGate; 
-                pGate->pTwin = pBase; 
-                printf( "Gate \"%s\" appears more than once. Creating multi-output gate.\n", pGate->pName );
+                Mio_Gate_t * pBase = Mio_LibraryReadGateByName( pLib, pGate->pName, NULL );
+                if ( pBase->pTwin != NULL )
+                {
+                    printf( "Gates with more than 2 outputs are not supported.\n" );
+                    continue;
+                }
+                pBase->pTwin = pGate;
+                pGate->pTwin = pBase;
+                printf( "Gate \"%s\" appears two times. Creating a 2-output gate.\n", pGate->pName );
             }
         }
     }
diff --git a/src/map/mio/mioUtils.c b/src/map/mio/mioUtils.c
index fcc59dcc..41b03d7d 100644
--- a/src/map/mio/mioUtils.c
+++ b/src/map/mio/mioUtils.c
@@ -164,6 +164,18 @@ int Mio_CheckPins( Mio_Pin_t * pPin1, Mio_Pin_t * pPin2 )
         return 0;
     return 1;
 }
+int Mio_CheckGates( Mio_Library_t * pLib )
+{
+    Mio_Gate_t * pGate;
+    Mio_Pin_t * pPin0 = NULL, * pPin = NULL;
+    Mio_LibraryForEachGate( pLib, pGate )
+        Mio_GateForEachPin( pGate, pPin )
+            if ( Mio_CheckPins( pPin0, pPin ) )
+                pPin0 = pPin;
+            else
+                return 0;
+    return 1;
+}
 
 /**Function*************************************************************
 
@@ -182,7 +194,7 @@ void Mio_WritePin( FILE * pFile, Mio_Pin_t * pPin, int NameLen, int fAllPins )
     if ( fAllPins )
         fprintf( pFile, "PIN *  " );
     else
-        fprintf( pFile, "\n     PIN %*s  ", NameLen, pPin->pName );
+        fprintf( pFile, "\n    PIN %*s  ", NameLen, pPin->pName );
     fprintf( pFile, "%7s ",   pPhaseNames[pPin->Phase] );
     fprintf( pFile, "%3d ",   (int)pPin->dLoadInput );
     fprintf( pFile, "%3d ",   (int)pPin->dLoadMax );
@@ -203,29 +215,23 @@ void Mio_WritePin( FILE * pFile, Mio_Pin_t * pPin, int NameLen, int fAllPins )
   SeeAlso     []
 
 ***********************************************************************/
-void Mio_WriteGate( FILE * pFile, Mio_Gate_t * pGate, int GateLen, int NameLen, int FormLen, int fPrintSops )
+void Mio_WriteGate( FILE * pFile, Mio_Gate_t * pGate, int GateLen, int NameLen, int FormLen, int fPrintSops, int fAllPins )
 {
     char Buffer[5000];
-    Mio_Pin_t * pPin = NULL, * pPin0 = NULL;
+    Mio_Pin_t * pPin;
     assert( NameLen+FormLen+2 < 5000 );
     sprintf( Buffer, "%s=%s;",    pGate->pOutName, pGate->pForm );
     fprintf( pFile, "GATE %-*s ", GateLen, pGate->pName );
     fprintf( pFile, "%8.2f  ",    pGate->dArea );
-    fprintf( pFile, "%-*s ",      NameLen+FormLen+2, Buffer );
-    // compare pins and decide if their properties are the same
-    Mio_GateForEachPin( pGate, pPin )
-        if ( Mio_CheckPins( pPin0, pPin ) )
-            pPin0 = pPin;
-        else
-            break;
+    fprintf( pFile, "%-*s ",      Abc_MinInt(NameLen+FormLen+2, 30), Buffer );
     // print the pins
     if ( fPrintSops )
         fprintf( pFile, "%s",       pGate->pSop? pGate->pSop : "unspecified\n" );
-    if ( pPin != NULL ) // different pins
+    if ( fAllPins && pGate->pPins ) // equal pins
+        Mio_WritePin( pFile, pGate->pPins, NameLen, 1 );
+    else // different pins
         Mio_GateForEachPin( pGate, pPin )
             Mio_WritePin( pFile, pPin, NameLen, 0 );
-    else if ( pPin0 != NULL ) // equal pins
-        Mio_WritePin( pFile, pPin0, NameLen, 1 );
     fprintf( pFile, "\n" );
 }
 
@@ -245,6 +251,7 @@ void Mio_WriteLibrary( FILE * pFile, Mio_Library_t * pLib, int fPrintSops )
     Mio_Gate_t * pGate;
     Mio_Pin_t * pPin;
     int i, GateLen = 0, NameLen = 0, FormLen = 0;
+    int fAllPins = Mio_CheckGates( pLib );
     Mio_LibraryForEachGate( pLib, pGate )
     {
         GateLen = Abc_MaxInt( GateLen, strlen(pGate->pName) );
@@ -255,7 +262,7 @@ void Mio_WriteLibrary( FILE * pFile, Mio_Library_t * pLib, int fPrintSops )
     }
     fprintf( pFile, "# The genlib library \"%s\".\n", pLib->pName );
     for ( i = 0; i < pLib->nGates; i++ )
-        Mio_WriteGate( pFile, pLib->ppGates0[i], GateLen, NameLen, FormLen, fPrintSops );
+        Mio_WriteGate( pFile, pLib->ppGates0[i], GateLen, NameLen, FormLen, fPrintSops, fAllPins );
 }
 
 /**Function*************************************************************
diff --git a/src/map/scl/sclUtil.c b/src/map/scl/sclUtil.c
index a9b94902..dc513d56 100644
--- a/src/map/scl/sclUtil.c
+++ b/src/map/scl/sclUtil.c
@@ -232,7 +232,7 @@ void Abc_SclManSetGates( SC_Lib * pLib, Abc_Ntk_t * p, Vec_Int_t * vGates )
     {
         SC_Cell * pCell = SC_LibCell( pLib, Vec_IntEntry(vGates, Abc_ObjId(pObj)) );
         assert( pCell->n_inputs == Abc_ObjFaninNum(pObj) );
-        pObj->pData = Mio_LibraryReadGateByName( (Mio_Library_t *)p->pManFunc, pCell->pName );
+        pObj->pData = Mio_LibraryReadGateByName( (Mio_Library_t *)p->pManFunc, pCell->pName, NULL );
 //printf( "Found gate %s\n", pCell->name );
     }
 }