Adding 'zeropo -o' to replace a given PO by const 1.

src/base/abc/abcNtk.c

@@ -1717,7 +1717,7 @@ void Abc_NtkDropSatOutputs( Abc_Ntk_t * pNtk, Vec_Ptr_t * vCexes, int fVerbose )
   SeeAlso     []
 
 ***********************************************************************/
-void Abc_NtkDropOneOutput( Abc_Ntk_t * pNtk, int iOutput, int fSkipSweep )
+void Abc_NtkDropOneOutput( Abc_Ntk_t * pNtk, int iOutput, int fSkipSweep, int fUseConst1 )
 {
     Abc_Obj_t * pObj, * pConst0, * pFaninNew;
     pObj = Abc_NtkPo( pNtk, iOutput );
@@ -1727,7 +1727,7 @@ void Abc_NtkDropOneOutput( Abc_Ntk_t * pNtk, int iOutput, int fSkipSweep )
             Abc_ObjXorFaninC( pObj, 0 );
         return;
     }
-    pConst0 = Abc_ObjNot( Abc_AigConst1(pNtk) );
+    pConst0 = Abc_ObjNotCond( Abc_AigConst1(pNtk), !fUseConst1 );
     pFaninNew = Abc_ObjNotCond( pConst0, Abc_ObjFaninC0(pObj) );
     Abc_ObjPatchFanin( pObj, Abc_ObjFanin0(pObj), pFaninNew );
     assert( Abc_ObjChild0(pObj) == pConst0 );

src/base/abci/abc.c

@@ -6536,11 +6536,12 @@ int Abc_CommandZeroPo( Abc_Frame_t * pAbc, int argc, char ** argv )
     Abc_Ntk_t * pNtk = Abc_FrameReadNtk(pAbc);//, * pNtkRes = NULL;
     int c, iOutput = -1;
     int fSkipSweep = 0;
-    extern void Abc_NtkDropOneOutput( Abc_Ntk_t * pNtk, int iOutput, int fSkipSweep );
+    int fUseConst1 = 0;
+    extern void Abc_NtkDropOneOutput( Abc_Ntk_t * pNtk, int iOutput, int fSkipSweep, int fUseConst1 );
 
     // set defaults
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "Nsh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "Nsoh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -6558,6 +6559,9 @@ int Abc_CommandZeroPo( Abc_Frame_t * pAbc, int argc, char ** argv )
         case 's':
             fSkipSweep ^= 1;
             break;
+        case 'o':
+            fUseConst1 ^= 1;
+            break;
         default:
             goto usage;
         }
@@ -6589,14 +6593,15 @@ int Abc_CommandZeroPo( Abc_Frame_t * pAbc, int argc, char ** argv )
 //    pNtkRes = Abc_NtkDup( pNtk );
 //    Abc_NtkDropOneOutput( pNtkRes, iOutput );
 //    Abc_FrameReplaceCurrentNetwork( pAbc, pNtkRes );
-    Abc_NtkDropOneOutput( pNtk, iOutput, fSkipSweep );
+    Abc_NtkDropOneOutput( pNtk, iOutput, fSkipSweep, fUseConst1 );
     return 0;
 
 usage:
-    Abc_Print( -2, "usage: zeropo [-N <num>] [-sh]\n" );
+    Abc_Print( -2, "usage: zeropo [-N <num>] [-soh]\n" );
     Abc_Print( -2, "\t           replaces the PO driver by constant 0\n" );
     Abc_Print( -2, "\t-N <num> : the zero-based index of the PO to replace [default = %d]\n", iOutput );
     Abc_Print( -2, "\t-s       : performs comb sweep after removimg a PO [default = %s]\n", !fSkipSweep? "yes": "no" );
+    Abc_Print( -2, "\t-o       : toggles using const 1 instead of const 0 [default = %s]\n", fUseConst1? "yes": "no" );
     Abc_Print( -2, "\t-h       : print the command usage\n");
     return 1;
 }