py: Add MP_OBJ_STOP_ITERATION and make good use of it.

Also make consistent use of MP_OBJ_NOT_SUPPORTED and MP_OBJ_NULL.
This helps a lot in debugging and understanding of function API.

1 files changed, 3 insertions, 4 deletions

diff --git a/py/objint_longlong.c b/py/objint_longlong.c
index 7dc0573bc6..7d71c5a691 100644
--- a/py/objint_longlong.c
+++ b/py/objint_longlong.c
@@ -37,7 +37,7 @@ mp_obj_t mp_obj_int_unary_op(int op, mp_obj_t o_in) {
         case MP_UNARY_OP_POSITIVE: return o_in;
         case MP_UNARY_OP_NEGATIVE: return mp_obj_new_int_from_ll(-o->val);
         case MP_UNARY_OP_INVERT: return mp_obj_new_int_from_ll(~o->val);
-        default: return NULL; // op not supported
+        default: return MP_OBJ_NOT_SUPPORTED;
     }
 }
 
@@ -50,7 +50,7 @@ mp_obj_t mp_obj_int_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
     } else if (MP_OBJ_IS_TYPE(lhs_in, &mp_type_int)) {
         lhs_val = ((mp_obj_int_t*)lhs_in)->val;
     } else {
-        return MP_OBJ_NULL;
+        return MP_OBJ_NOT_SUPPORTED;
     }
 
     if (MP_OBJ_IS_SMALL_INT(rhs_in)) {
@@ -108,8 +108,7 @@ mp_obj_t mp_obj_int_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
             return MP_BOOL(lhs_val == rhs_val);
 
         default:
-            // op not supported
-            return MP_OBJ_NULL;
+            return MP_OBJ_NOT_SUPPORTED;
     }
 }