Adding switch -x to command &fadds.

src/aig/gia/giaFadds.c

@@ -765,7 +765,7 @@ int Gia_ObjFanin1CopyCarry( Vec_Int_t * vCarries, Gia_Obj_t * pObj, int Id )
         return Gia_ObjFanin1Copy(pObj);
     return Abc_LitNotCond( Vec_IntEntry(vCarries, Gia_ObjFaninId1(pObj, Id)), Gia_ObjFaninC1(pObj) );
 }
-Gia_Man_t * Gia_ManDupWithArtificalFaddBoxes( Gia_Man_t * p, int fUseFanout )
+Gia_Man_t * Gia_ManDupWithArtificalFaddBoxes( Gia_Man_t * p, int fUseFanout, int fXorTrick )
 {
     Gia_Man_t * pNew;
     Gia_Obj_t * pObj;  
@@ -821,7 +821,7 @@ Gia_Man_t * Gia_ManDupWithArtificalFaddBoxes( Gia_Man_t * p, int fUseFanout )
             pObj->Value = Gia_ManAppendAnd( pNew, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
         else // AND-gate with chain
         {
-            int iCiLit, iOtherLit, iLit0, iLit1, iLit2;
+            int iCiLit, iOtherLit, iLit0, iLit1, iLit2, iXorLit;
             assert( pObj->fMark0 != pObj->fMark1 );
             iCiLit    = pObj->fMark0 ? Gia_ObjFanin0CopyCarry(vCarries, pObj, i) : Gia_ObjFanin1CopyCarry(vCarries, pObj, i);
             iOtherLit = pObj->fMark0 ? Gia_ObjFanin1Copy(pObj) : Gia_ObjFanin0Copy(pObj);
@@ -835,14 +835,19 @@ Gia_Man_t * Gia_ManDupWithArtificalFaddBoxes( Gia_Man_t * p, int fUseFanout )
             Gia_ManAppendCo( pNew, iLit1 );
             Gia_ManAppendCo( pNew, iLit2 );
             // add CI (unused sum bit)
-            Gia_ManAppendCi(pNew);
+            iXorLit = Gia_ManAppendCi(pNew);
             // add CI (carry bit)
             pObj->Value = Abc_LitNotCond( Gia_ManAppendCi(pNew), Abc_LitIsCompl(iCiLit) );
             if ( vCarries && pObj->fPhase )
             {
                 Vec_IntWriteEntry( vCarries, i, pObj->Value );
                 if ( Gia_ObjRefNum(p, pObj) > 0 )
-                    pObj->Value = Gia_ManAppendAnd( pNew, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
+                {
+                    if ( fXorTrick )
+                        pObj->Value = Gia_ManAppendAnd( pNew, Abc_LitNotCond(iXorLit, !Abc_LitIsCompl(iCiLit)), iOtherLit );
+                    else
+                        pObj->Value = Gia_ManAppendAnd( pNew, Gia_ObjFanin0Copy(pObj), Gia_ObjFanin1Copy(pObj) );
+                }
             }
             nBoxes++;
         }
@@ -877,7 +882,7 @@ Gia_Man_t * Gia_ManDupWithArtificalFaddBoxesTest( Gia_Man_t * p )
     }
 
     // output new AIG
-    pNew = Gia_ManDupWithArtificalFaddBoxes( p, 0 );
+    pNew = Gia_ManDupWithArtificalFaddBoxes( p, 0, 0 );
     Gia_ManCleanMark01( p );
     return pNew;
 }
@@ -1079,7 +1084,7 @@ int Gia_ManIteratePaths( Gia_Man_t * p, int DelayC, int nPathMin, int nPathMax,
     return 1;
 }
 // annotate artificial chains and then put them into boxes
-Gia_Man_t * Gia_ManDupWithArtificialBoxes( Gia_Man_t * p, int DelayC, int nPathMin, int nPathMax, int nPathLimit, int fUseFanout, int fIgnoreBoxDelays, int fVerbose )
+Gia_Man_t * Gia_ManDupWithArtificialBoxes( Gia_Man_t * p, int DelayC, int nPathMin, int nPathMax, int nPathLimit, int fUseFanout, int fXorTrick, int fIgnoreBoxDelays, int fVerbose )
 {
     Gia_Man_t * pNew;
 /*
@@ -1090,7 +1095,7 @@ Gia_Man_t * Gia_ManDupWithArtificialBoxes( Gia_Man_t * p, int DelayC, int nPathM
     }
 */
     Gia_ManIteratePaths( p, DelayC, nPathMin, nPathMax, nPathLimit, fIgnoreBoxDelays, fVerbose );
-    pNew = Gia_ManDupWithArtificalFaddBoxes( p, fUseFanout );
+    pNew = Gia_ManDupWithArtificalFaddBoxes( p, fUseFanout, fXorTrick );
     Gia_ManCleanMark01( p );
     return pNew;
 }

src/base/abci/abc.c

@@ -36947,12 +36947,12 @@ usage:
 int Abc_CommandAbc9Fadds( Abc_Frame_t * pAbc, int argc, char ** argv )
 {
     extern Gia_Man_t * Gia_ManDupWithNaturalBoxes( Gia_Man_t * p, int nFaddMin, int fVerbose );
-    extern Gia_Man_t * Gia_ManDupWithArtificialBoxes( Gia_Man_t * p, int DelayC, int nPathMin, int nPathMax, int nPathLimit, int fUseFanout, int fIgnoreBoxDelays, int fVerbose );
+    extern Gia_Man_t * Gia_ManDupWithArtificialBoxes( Gia_Man_t * p, int DelayC, int nPathMin, int nPathMax, int nPathLimit, int fUseFanout, int fXorTrick, int fIgnoreBoxDelays, int fVerbose );
     Gia_Man_t * pTemp, * pTemp2;
     int c, nFaddMin = 3, fUseNat = 0, fUseArt = 0, fVerbose = 0;
-    int DelayC = 0, nPathMin = 3, nPathMax = 32, nPathLimit = 50, fUseFanout = 0, fIgnoreBoxDelays = 0;
+    int DelayC = 0, nPathMin = 3, nPathMax = 32, nPathLimit = 50, fUseFanout = 0, fUseXorTrick = 0, fIgnoreBoxDelays = 0;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "NBSLPnafbvh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "NBSLPnafxbvh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -37020,6 +37020,9 @@ int Abc_CommandAbc9Fadds( Abc_Frame_t * pAbc, int argc, char ** argv )
         case 'f':
             fUseFanout ^= 1;
             break;
+        case 'x':
+            fUseXorTrick ^= 1;
+            break;
         case 'b':
             fIgnoreBoxDelays ^= 1;
             break;
@@ -37045,7 +37048,7 @@ int Abc_CommandAbc9Fadds( Abc_Frame_t * pAbc, int argc, char ** argv )
         Gia_ManTransferTiming( pTemp, pAbc->pGia );
     }
     if ( fUseArt )
-        pTemp2 = Gia_ManDupWithArtificialBoxes( pTemp, DelayC, nPathMin, nPathMax, nPathLimit, fUseFanout, fIgnoreBoxDelays, fVerbose );
+        pTemp2 = Gia_ManDupWithArtificialBoxes( pTemp, DelayC, nPathMin, nPathMax, nPathLimit, fUseFanout, fUseXorTrick, fIgnoreBoxDelays, fVerbose );
     else
     {
         pTemp2 = Gia_ManDup( pTemp );
@@ -37055,7 +37058,7 @@ int Abc_CommandAbc9Fadds( Abc_Frame_t * pAbc, int argc, char ** argv )
     Abc_FrameUpdateGia( pAbc, pTemp2 );
     return 0;
 usage:
-    Abc_Print( -2, "usage: &fadds [-NBSLP num] [-nafvh]\n" );
+    Abc_Print( -2, "usage: &fadds [-NBSLP num] [-nafxvh]\n" );
     Abc_Print( -2, "\t         detects full-adder chains and puts them into white boxes\n" );
     Abc_Print( -2, "\t-n     : toggles detecting natural full-adder chains [default = %s]\n",              fUseNat? "yes": "no" );
     Abc_Print( -2, "\t-N num : minimum length of a natural full-adder chain to detect [default = %d]\n",   nFaddMin );
@@ -37065,6 +37068,7 @@ usage:
     Abc_Print( -2, "\t-L num : maximum length of an artificial full-adder chain [default = %d]\n",         nPathMax );
     Abc_Print( -2, "\t-P num : maximum number of artificial full-adder chains to detect [default = %d]\n", nPathLimit );
     Abc_Print( -2, "\t-f     : toggles allowing external fanouts in artificial chains [default = %s]\n",   fUseFanout? "yes": "no" );
+    Abc_Print( -2, "\t-x     : toggles using XOR to generate fanouts in artificial chains [default = %s]\n",   fUseXorTrick? "yes": "no" );
     Abc_Print( -2, "\t-b     : toggles ignoring boxes when computing delays [default = %s]\n",             fIgnoreBoxDelays? "yes": "no" );
     Abc_Print( -2, "\t-v     : toggles printing verbose information [default = %s]\n",                     fVerbose? "yes": "no" );
     Abc_Print( -2, "\t-h     : print the command usage\n");