diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index b46f4c8013..1dffcee884 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -3479,8 +3479,8 @@ static ExitStatus op_risbg(DisasContext *s, DisasOps *o)
     }
 
     /* In some cases we can implement this with extract.  */
-    if (imask == 0 && pos == 0 && len > 0 && rot + len <= 64) {
-        tcg_gen_extract_i64(o->out, o->in2, rot, len);
+    if (imask == 0 && pos == 0 && len > 0 && len <= rot) {
+        tcg_gen_extract_i64(o->out, o->in2, 64 - rot, len);
         return NO_EXIT;
     }