ntdll: Fix single stepping over popf instruction.

dlls/ntdll/signal_i386.c

@@ -1019,11 +1019,15 @@ static void WINAPI raise_trap_exception( EXCEPTION_RECORD *rec, CONTEXT *context
         {
             context->ContextFlags = CONTEXT_DEBUG_REGISTERS;
             NtGetContextThread(GetCurrentThread(), context);
-            /* do we really have a bp from a debug register ?
-             * if not, then someone did a kill(SIGTRAP) on us, and we
-             * shall return a breakpoint, not a single step exception
+            /* we have either:
+             *    - a bp from a debug register
+             *    - a single step interrupt at popf instruction, which just has
+             *      removed the TF.
+             *    - someone did a kill(SIGTRAP) on us, and we shall return
+             *      a breakpoint, not a single step exception
              */
-            if (!(context->Dr6 & 0xf)) rec->ExceptionCode = EXCEPTION_BREAKPOINT;
+            if ( !(context->Dr6 & 0xf) && !(context->Dr6 & 0x4000) )
+                rec->ExceptionCode = EXCEPTION_BREAKPOINT;
             context->ContextFlags |= CONTEXT_FULL;  /* restore flags */
         }
     }

dlls/ntdll/tests/exception.c

@@ -265,8 +265,8 @@ static DWORD single_step_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_
     else {
         /* show that the last single step exception on the popf instruction
          * (which removed the TF bit), still is a EXCEPTION_SINGLE_STEP exception */
-        todo_wine { ok( rec->ExceptionCode == EXCEPTION_SINGLE_STEP,
-            "exception is not EXCEPTION_SINGLE_STEP: %x\n", rec->ExceptionCode); };
+        ok( rec->ExceptionCode == EXCEPTION_SINGLE_STEP,
+            "exception is not EXCEPTION_SINGLE_STEP: %x\n", rec->ExceptionCode);
     }
 
     return ExceptionContinueExecution;