target-arm: Fix VQSHL of signed 64 bit values by shift counts >= 64

VQSHL of a signed 64 bit non-zero value by a shift count >= 64 should
saturate; return the correct value in this case.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

diff --git a/target-arm/neon_helper.c b/target-arm/neon_helper.c
index d29b884614cdbc831c7818ef1cacdefb885dd209..2dc3d96dba9dc080033e7e2d37c69e7b138a28ea 100644 (file)
--- a/target-arm/neon_helper.c
+++ b/target-arm/neon_helper.c
@@ -608,7 +608,7 @@ uint64_t HELPER(neon_qshl_s64)(CPUState *env, uint64_t valop, uint64_t shiftop)
     if (shift >= 64) {
         if (val) {
             SET_QC();
-            val = (val >> 63) & ~SIGNBIT64;
+            val = (val >> 63) ^ ~SIGNBIT64;
         }
     } else if (shift <= -64) {
         val >>= 63;