[Qemu-devel] [PATCH] target/arm: Fix sign-extension for SMLAL*

[Richard Henderson]

The 32-bit product should be sign-extended, not zero-extended.

Fixes: ea96b374641b
Reported-by: Laurent Desnogues <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
 target/arm/translate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 34bb280e3d..fd2f0e3048 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -8045,7 +8045,9 @@ static bool op_smlaxxx(DisasContext *s, arg_rrrr *a,
     case 2:
         tl = load_reg(s, a->ra);
         th = load_reg(s, a->rd);
-        t1 = tcg_const_i32(0);
+        /* Sign-extend the 32-bit product to 64 bits.  */
+        t1 = tcg_temp_new_i32();
+        tcg_gen_sari_i32(t1, t0, 31);
         tcg_gen_add2_i32(tl, th, tl, th, t0, t1);
         tcg_temp_free_i32(t0);
         tcg_temp_free_i32(t1);
-- 
2.17.1