diff --git a/target-ppc/op.c b/target-ppc/op.c
index 64166595cf..4ab0f00433 100644
--- a/target-ppc/op.c
+++ b/target-ppc/op.c
@@ -798,7 +798,11 @@ void OPPROTO op_mulli (void)
 /* multiply low word */
 void OPPROTO op_mullw (void)
 {
+#if defined(TARGET_PPC64)
+    T0 = (int64_t)(int32_t)T0 * (int64_t)(int32_t)T1;
+#else
     T0 = (int32_t)(T0 * T1);
+#endif
     RETURN();
 }
 
diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
index 46e9b7ab6c..d398640278 100644
--- a/target-ppc/op_helper.c
+++ b/target-ppc/op_helper.c
@@ -227,7 +227,7 @@ void do_divduo (void)
 
 void do_mullwo (void)
 {
-    int64_t res = (int64_t)T0 * (int64_t)T1;
+    int64_t res = (int64_t)(int32_t)T0 * (int64_t)(int32_t)T1;
 
     if (likely((int32_t)res == res)) {
         xer_ov = 0;