@@ -63,6 +63,19 @@ static void handle_exceptions(CPUS390XState *env, uintptr_t retaddr)
env->fpu_status.float_exception_flags = 0;
s390_exc = s390_softfloat_exc_to_ieee(qemu_exc);
+ /*
+ * IEEE-Underflow exception recognition exists if a tininess condition
+ * (underflow) exists and
+ * - The mask bit in the FPC is zero and the result is inexact
+ * - The mask bit in the FPC is one
+ * So tininess conditions that are not inexact don't trigger any
+ * underflow action in case the mask bit is not one.
+ */
+ if (!(s390_exc & S390_IEEE_MASK_INEXACT) &&
+ !((env->fpc >> 24) & S390_IEEE_MASK_UNDERFLOW)) {
+ s390_exc &= ~S390_IEEE_MASK_UNDERFLOW;
+ }
+
/*
* FIXME:
* 1. Right now, all inexact conditions are inidicated as