Fixing the wire-load approximation problem.

src/base/abc/abc.h

@@ -965,6 +965,7 @@ extern ABC_DLL int                Abc_NtkGetMuxNum( Abc_Ntk_t * pNtk );
 extern ABC_DLL int                Abc_NtkGetBufNum( Abc_Ntk_t * pNtk );
 extern ABC_DLL int                Abc_NtkGetChoiceNum( Abc_Ntk_t * pNtk );
 extern ABC_DLL int                Abc_NtkGetFaninMax( Abc_Ntk_t * pNtk );
+extern ABC_DLL int                Abc_NtkGetFanoutMax( Abc_Ntk_t * pNtk );
 extern ABC_DLL int                Abc_NtkGetTotalFanins( Abc_Ntk_t * pNtk );
 extern ABC_DLL void               Abc_NtkCleanCopy( Abc_Ntk_t * pNtk );
 extern ABC_DLL void               Abc_NtkCleanData( Abc_Ntk_t * pNtk );

src/base/abc/abcUtil.c

@@ -459,6 +459,17 @@ int Abc_NtkGetFaninMax( Abc_Ntk_t * pNtk )
     }
     return nFaninsMax;
 }
+int Abc_NtkGetFanoutMax( Abc_Ntk_t * pNtk )
+{
+    Abc_Obj_t * pNode;
+    int i, nFaninsMax = 0;
+    Abc_NtkForEachNode( pNtk, pNode, i )
+    {
+        if ( nFaninsMax < Abc_ObjFanoutNum(pNode) )
+            nFaninsMax = Abc_ObjFanoutNum(pNode);
+    }
+    return nFaninsMax;
+}
 
 /**Function*************************************************************
 

src/map/scl/sclBufSize.c

@@ -94,7 +94,7 @@ Bus_Man_t * Bus_ManStart( Abc_Ntk_t * pNtk, SC_Lib * pLib, SC_BusPars * pPars )
             p->pWLoadUsed = Abc_SclFetchWireLoadModel( pLib, pNtk->pWLoadUsed );
     }
     if ( p->pWLoadUsed )
-    p->vWireCaps = Abc_SclFindWireCaps( p->pWLoadUsed );
+    p->vWireCaps = Abc_SclFindWireCaps( p->pWLoadUsed, Abc_NtkGetFanoutMax(pNtk) );
     p->vFanouts  = Vec_PtrAlloc( 100 );
     p->vCins     = Vec_FltAlloc( 2*Abc_NtkObjNumMax(pNtk) + 1000 );
     p->vETimes   = Vec_FltAlloc( 2*Abc_NtkObjNumMax(pNtk) + 1000 );

src/map/scl/sclLib.h

@@ -40,7 +40,7 @@ ABC_NAMESPACE_HEADER_START
 ///                         PARAMETERS                               ///
 ////////////////////////////////////////////////////////////////////////
 
-#define ABC_SCL_CUR_VERSION 6
+#define ABC_SCL_CUR_VERSION 7
 
 typedef enum  
 {
@@ -117,8 +117,8 @@ typedef struct SC_Lib_         SC_Lib;
 struct SC_WireLoad_ 
 {
     char *         pName;
-    float          res;            // (currently not used)
     float          cap;            // }- multiply estimation in 'fanout_len[].snd' with this value
+    float          slope;          // used to extrapolate wireload for large fanout count
     Vec_Int_t *    vFanout;        // Vec<Pair<uint,float> > -- pairs '(#fanouts, est-wire-len)'
     Vec_Flt_t *    vLen;
 };

src/map/scl/sclLibScl.c

@@ -71,11 +71,16 @@ static void Abc_SclReadSurface( Vec_Str_t * vOut, int * pPos, SC_Surface * p )
     for ( i = 0; i < 6; i++ ) 
         p->approx[2][i] = Vec_StrGetF( vOut, pPos );
 }
-static void Abc_SclReadLibrary( Vec_Str_t * vOut, int * pPos, SC_Lib * p )
+static int Abc_SclReadLibrary( Vec_Str_t * vOut, int * pPos, SC_Lib * p )
 {
     int i, j, k, n;
     int version = Vec_StrGetI( vOut, pPos );
-    assert( version == 5 || version == ABC_SCL_CUR_VERSION ); // wrong version of the file
+    if ( version != ABC_SCL_CUR_VERSION )
+    { 
+        Abc_Print( -1, "Wrong version of the SCL file.\n" ); 
+        return 0; 
+    }
+    assert( version == ABC_SCL_CUR_VERSION ); // wrong version of the file
 
     // Read non-composite fields:
     p->pName                 = Vec_StrGetS(vOut, pPos);
@@ -94,8 +99,8 @@ static void Abc_SclReadLibrary( Vec_Str_t * vOut, int * pPos, SC_Lib * p )
         Vec_PtrPush( p->vWireLoads, pWL );
 
         pWL->pName = Vec_StrGetS(vOut, pPos);
-        pWL->res  = Vec_StrGetF(vOut, pPos);
         pWL->cap   = Vec_StrGetF(vOut, pPos);
+        pWL->slope = Vec_StrGetF(vOut, pPos);
 
         for ( j = Vec_StrGetI(vOut, pPos); j != 0; j-- )
         {
@@ -163,16 +168,6 @@ static void Abc_SclReadLibrary( Vec_Str_t * vOut, int * pPos, SC_Lib * p )
             assert( k == pCell->n_inputs );
 
             // read function
-            if ( version == 5 )
-            { 
-                // formula is not given
-                assert( Vec_WrdSize(pPin->vFunc) == 0 );
-                Vec_WrdGrow( pPin->vFunc, Abc_Truth6WordNum(pCell->n_inputs) );
-                for ( k = 0; k < Vec_WrdCap(pPin->vFunc); k++ )
-                    Vec_WrdPush( pPin->vFunc, Vec_StrGetW(vOut, pPos) );
-            }
-            else
-            {
             // (possibly empty) formula is always given
             assert( version == ABC_SCL_CUR_VERSION );
             assert( pPin->func_text == NULL );
@@ -208,7 +203,6 @@ static void Abc_SclReadLibrary( Vec_Str_t * vOut, int * pPos, SC_Lib * p )
                     assert( Value == Vec_WrdEntry(pPin->vFunc, k) );
                 }
             }
-            }
 
             // Read 'rtiming': (pin-to-pin timing tables for this particular output)
             for ( k = 0; k < pCell->n_inputs; k++ )
@@ -234,6 +228,7 @@ static void Abc_SclReadLibrary( Vec_Str_t * vOut, int * pPos, SC_Lib * p )
             }
         }
     }
+    return 1;
 }
 SC_Lib * Abc_SclReadFromStr( Vec_Str_t * vOut )
 {
@@ -241,7 +236,8 @@ SC_Lib * Abc_SclReadFromStr( Vec_Str_t * vOut )
     int Pos = 0;
     // read the library
     p = Abc_SclLibAlloc();
-    Abc_SclReadLibrary( vOut, &Pos, p );
+    if ( !Abc_SclReadLibrary( vOut, &Pos, p ) )
+        return NULL;
     assert( Pos == Vec_StrSize(vOut) );
     // hash gates by name
     Abc_SclHashCells( p );
@@ -273,7 +269,9 @@ SC_Lib * Abc_SclReadFromFile( char * pFileName )
     fclose( pFile );
     // read the library
     p = Abc_SclReadFromStr( vOut );
+    if ( p != NULL )
         p->pFileName = Abc_UtilStrsav( pFileName );
+    if ( p != NULL )
         Abc_SclLibNormalize( p );
     Vec_StrFree( vOut );
     return p;
@@ -343,8 +341,8 @@ static void Abc_SclWriteLibrary( Vec_Str_t * vOut, SC_Lib * p )
     SC_LibForEachWireLoad( p, pWL, i )
     {
         Vec_StrPutS( vOut, pWL->pName );
-        Vec_StrPutF( vOut, pWL->res );
         Vec_StrPutF( vOut, pWL->cap );
+        Vec_StrPutF( vOut, pWL->slope );
 
         Vec_StrPutI( vOut, Vec_IntSize(pWL->vFanout) );
         for ( j = 0; j < Vec_IntSize(pWL->vFanout); j++ )
@@ -553,8 +551,8 @@ static void Abc_SclWriteLibraryText( FILE * s, SC_Lib * p )
     SC_LibForEachWireLoad( p, pWL, i )
     {
         fprintf( s, "  wire_load(\"%s\") {\n", pWL->pName );
-        fprintf( s, "    resistance : %f;\n", pWL->res );
         fprintf( s, "    capacitance : %f;\n", pWL->cap );
+        fprintf( s, "    slope : %f;\n", pWL->slope );
         for ( j = 0; j < Vec_IntSize(pWL->vFanout); j++ )
             fprintf( s, "    fanout_length( %d, %f );\n", Vec_IntEntry(pWL->vFanout, j), Vec_FltEntry(pWL->vLen, j) );
         fprintf( s, "  }\n\n" );

src/map/scl/sclLiberty.c

@@ -811,10 +811,10 @@ void Scl_LibertyReadWireLoad( Scl_Tree_t * p, Vec_Str_t * vOut )
     Scl_ItemForEachChildName( p, Scl_LibertyRoot(p), pItem, "wire_load" )
     {
         Vec_StrPutS_( vOut, Scl_LibertyReadString(p, pItem->Head) );
-        Scl_ItemForEachChildName( p, pItem, pChild, "resistance" )
-            Vec_StrPutF_( vOut, atof(Scl_LibertyReadString(p, pChild->Head)) );
         Scl_ItemForEachChildName( p, pItem, pChild, "capacitance" )
             Vec_StrPutF_( vOut, atof(Scl_LibertyReadString(p, pChild->Head)) );
+        Scl_ItemForEachChildName( p, pItem, pChild, "slope" )
+            Vec_StrPutF_( vOut, atof(Scl_LibertyReadString(p, pChild->Head)) );
         Vec_StrPut_( vOut );
         Vec_StrPutI_( vOut, Scl_LibertyItemNum(p, pItem, "fanout_length") );
         Vec_StrPut_( vOut );
@@ -1575,6 +1575,8 @@ SC_Lib * Abc_SclReadLiberty( char * pFileName, int fVerbose, int fVeryVerbose )
     Scl_LibertyStop( p, fVeryVerbose );
     // construct SCL data-structure
     pLib = Abc_SclReadFromStr( vStr );
+    if ( pLib == NULL )
+        return NULL;
     pLib->pFileName = Abc_UtilStrsav( pFileName );
     Abc_SclLibNormalize( pLib );
     Vec_StrFree( vStr );

src/map/scl/sclLoad.c

@@ -42,29 +42,41 @@ ABC_NAMESPACE_IMPL_START
   SeeAlso     []
 
 ***********************************************************************/
-Vec_Flt_t * Abc_SclFindWireCaps( SC_WireLoad * pWL )
+Vec_Flt_t * Abc_SclFindWireCaps( SC_WireLoad * pWL, int nFanoutMax )
 {
     Vec_Flt_t * vCaps = NULL;
-    float EntryPrev, EntryCur;
-    int i, Entry, EntryMax;
+    float EntryPrev, EntryCur, Slope;
+    int i, iPrev, k, Entry, EntryMax;
     assert( pWL != NULL );
-    // find the biggest fanout
+    // find the biggest fanout count
     EntryMax = 0;
     Vec_IntForEachEntry( pWL->vFanout, Entry, i )
         EntryMax = Abc_MaxInt( EntryMax, Entry );
     // create the array
-    vCaps = Vec_FltStart( EntryMax + 1 );
+    vCaps = Vec_FltStart( Abc_MaxInt(nFanoutMax, EntryMax) + 1 );
     Vec_IntForEachEntry( pWL->vFanout, Entry, i )
         Vec_FltWriteEntry( vCaps, Entry, Vec_FltEntry(pWL->vLen, i) * pWL->cap );
-    // reformat
-    EntryPrev = 0;
-    Vec_FltForEachEntry( vCaps, EntryCur, i )
+    // interpolate between the values
+    assert( Vec_FltEntry(vCaps, 1) != 0 );
+    iPrev = 1;
+    EntryPrev = Vec_FltEntry(vCaps, 1);
+    Vec_FltForEachEntryStart( vCaps, EntryCur, i, 2 )
     {
-        if ( EntryCur )
+        if ( EntryCur == 0 )
+            continue;
+        Slope = (EntryCur - EntryPrev) / (i - iPrev);
+        for ( k = iPrev + 1; k < i; k++ )
+            Vec_FltWriteEntry( vCaps, k, EntryPrev + Slope * (k - iPrev) );
         EntryPrev = EntryCur;
-        else
-            Vec_FltWriteEntry( vCaps, i, EntryPrev );
+        iPrev = i;
     }
+    // extrapolate after the largest value
+    Slope = pWL->cap * pWL->slope;
+    for ( k = iPrev + 1; k < i; k++ )
+        Vec_FltWriteEntry( vCaps, k, EntryPrev + Slope * (k - iPrev) );
+    // show
+//    Vec_FltForEachEntry( vCaps, EntryCur, i )
+//        printf( "%3d : %f\n", i, EntryCur );
     return vCaps;
 }
 
@@ -126,7 +138,7 @@ void Abc_SclComputeLoad( SC_Man * p )
     if ( p->pWLoadUsed != NULL )
     {
         if ( p->vWireCaps == NULL )
-            p->vWireCaps = Abc_SclFindWireCaps( p->pWLoadUsed );
+            p->vWireCaps = Abc_SclFindWireCaps( p->pWLoadUsed, Abc_NtkGetFanoutMax(p->pNtk) );
         Abc_NtkForEachNode1( p->pNtk, pObj, i )
             Abc_SclAddWireLoad( p, pObj, 0 );
         Abc_NtkForEachPi( p->pNtk, pObj, i )

src/map/scl/sclSize.h

@@ -553,7 +553,7 @@ extern Abc_Ntk_t *   Abc_SclBufPerform( Abc_Ntk_t * pNtk, int FanMin, int FanMax
 /*=== sclDnsize.c ===============================================================*/
 extern void          Abc_SclDnsizePerform( SC_Lib * pLib, Abc_Ntk_t * pNtk, SC_SizePars * pPars );
 /*=== sclLoad.c ===============================================================*/
-extern Vec_Flt_t *   Abc_SclFindWireCaps( SC_WireLoad * pWL );
+extern Vec_Flt_t *   Abc_SclFindWireCaps( SC_WireLoad * pWL, int nFanoutMax );
 extern float         Abc_SclFindWireLoad( Vec_Flt_t * vWireCaps, int nFans );
 extern void          Abc_SclAddWireLoad( SC_Man * p, Abc_Obj_t * pObj, int fSubtr );
 extern void          Abc_SclComputeLoad( SC_Man * p );