s390x/tcg: Fix simulated-IEEE exceptions

The trap is triggered based on priority of the enabled signaling flags.
Only overflow and underflow allow a concurrent inexact exception.

z14 PoP, 9-33, Figure 9-21

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190218122710.23639-8-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/target/s390x/fpu_helper.c b/target/s390x/fpu_helper.c
index ea5a37ac5e76535da238bdb06d34c168256d1f50..7508c0748e6364d9dfbed38779dc6ab9f58a310b 100644 (file)
--- a/target/s390x/fpu_helper.c
+++ b/target/s390x/fpu_helper.c
@@ -789,6 +789,19 @@ void HELPER(sfas)(CPUS390XState *env, uint64_t fpc)
      */
     s390_exc = (signalling >> 16) & (fpc >> 24);
     if (s390_exc) {
+        if (s390_exc & S390_IEEE_MASK_INVALID) {
+            s390_exc = S390_IEEE_MASK_INVALID;
+        } else if (s390_exc & S390_IEEE_MASK_DIVBYZERO) {
+            s390_exc = S390_IEEE_MASK_DIVBYZERO;
+        } else if (s390_exc & S390_IEEE_MASK_OVERFLOW) {
+            s390_exc &= (S390_IEEE_MASK_OVERFLOW | S390_IEEE_MASK_INEXACT);
+        } else if (s390_exc & S390_IEEE_MASK_UNDERFLOW) {
+            s390_exc &= (S390_IEEE_MASK_UNDERFLOW | S390_IEEE_MASK_INEXACT);
+        } else if (s390_exc & S390_IEEE_MASK_INEXACT) {
+            s390_exc = S390_IEEE_MASK_INEXACT;
+        } else if (s390_exc & S390_IEEE_MASK_QUANTUM) {
+            s390_exc = S390_IEEE_MASK_QUANTUM;
+        }
         tcg_s390_data_exception(env, s390_exc | 3, GETPC());
     }
 }