synco is a SH4-A only instruction.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
 target/sh4/translate.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/target/sh4/translate.c b/target/sh4/translate.c
index 7a504a7f5a..d61b176a7d 100644
--- a/target/sh4/translate.c
+++ b/target/sh4/translate.c
@@ -1569,10 +1569,11 @@ static void _decode_opc(DisasContext * ctx)
 	else
 	    break;
     case 0x00ab:		/* synco */
-	if (ctx->features & SH_FEATURE_SH4A)
-	    return;
-	else
-	    break;
+        if (ctx->features & SH_FEATURE_SH4A) {
+            tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
+            return;
+        }
+        break;
     case 0x4024:		/* rotcl Rn */
 	{
 	    TCGv tmp = tcg_temp_new();
-- 
2.11.0