diff --git a/target/mips/op_helper.c b/target/mips/op_helper.c
index 1f0e88364a..34bcc8d884 100644
--- a/target/mips/op_helper.c
+++ b/target/mips/op_helper.c
@@ -4742,11 +4742,11 @@ void helper_cache(CPUMIPSState *env, target_ulong addr, uint32_t op)
     if (op == 9) {
         /* Index Store Tag */
         memory_region_dispatch_write(env->itc_tag, index, env->CP0_TagLo,
-                                     size_memop(8), MEMTXATTRS_UNSPECIFIED);
+                                     MO_64, MEMTXATTRS_UNSPECIFIED);
     } else if (op == 5) {
         /* Index Load Tag */
         memory_region_dispatch_read(env->itc_tag, index, &env->CP0_TagLo,
-                                    size_memop(8), MEMTXATTRS_UNSPECIFIED);
+                                    MO_64, MEMTXATTRS_UNSPECIFIED);
     }
 #endif
 }