py, unix: Allow to compile with -Wsign-compare.

See issue #699.

1 files changed, 2 insertions, 2 deletions

diff --git a/py/obj.h b/py/obj.h
index 6caf50d842..0424048599 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -86,7 +86,7 @@ typedef struct _mp_obj_base_t mp_obj_base_t;
 #define MP_OBJ_SMALL_INT_VALUE(o) (((mp_int_t)(o)) >> 1)
 #define MP_OBJ_NEW_SMALL_INT(small_int) ((mp_obj_t)((((mp_int_t)(small_int)) << 1) | 1))
 
-#define MP_OBJ_QSTR_VALUE(o) (((mp_int_t)(o)) >> 2)
+#define MP_OBJ_QSTR_VALUE(o) (((mp_uint_t)(o)) >> 2)
 #define MP_OBJ_NEW_QSTR(qst) ((mp_obj_t)((((mp_uint_t)(qst)) << 2) | 2))
 
 // These macros are used to declare and define constant function objects
@@ -247,7 +247,7 @@ bool mp_get_buffer(mp_obj_t obj, mp_buffer_info_t *bufinfo, mp_uint_t flags);
 void mp_get_buffer_raise(mp_obj_t obj, mp_buffer_info_t *bufinfo, mp_uint_t flags);
 
 // Stream protocol
-#define MP_STREAM_ERROR (-1)
+#define MP_STREAM_ERROR ((mp_uint_t)-1)
 typedef struct _mp_stream_p_t {
     // On error, functions should return MP_STREAM_ERROR and fill in *errcode (values
     // are implementation-dependent, but will be exposed to user, e.g. via exception).