diff --git a/qad/utils/qpievaluator.cpp b/qad/utils/qpievaluator.cpp
index 8357c21..7acd1bf 100644
--- a/qad/utils/qpievaluator.cpp
+++ b/qad/utils/qpievaluator.cpp
@@ -873,9 +873,7 @@ inline void QPIEvaluator::execFunction(const QPIEvaluatorTypes::Instruction & ci
 		tmpvars[oi].value = atanc_qpie(value(ci.operators[0]));
 		break;
 	case QPIEvaluatorTypes::bfArcctg:
-		tmp = atanc_qpie(value(ci.operators[0]));
-		if (tmp == complexd_0) tmpvars[oi].value = 0.;
-		else tmpvars[oi].value = complexd_1 / tmp;
+		tmpvars[oi].value = atanc_qpie(-value(ci.operators[0])) + M_PI_2;
 		break;
 	case QPIEvaluatorTypes::bfSh:
 		tmpvars[oi].value = sinh(value(ci.operators[0]));