py: Use float-to-int classifications for mp_obj_new_int_from_float() functions

1 files changed, 13 insertions, 3 deletions

diff --git a/py/objint.c b/py/objint.c
index 370c6a5df..fd0b2be55 100644
--- a/py/objint.c
+++ b/py/objint.c
@@ -306,9 +306,19 @@ mp_obj_t mp_obj_new_int_from_uint(mp_uint_t value) {
 
 #if MICROPY_PY_BUILTINS_FLOAT
 mp_obj_t mp_obj_new_int_from_float(mp_float_t val) {
-    // TODO raise an exception if the int won't fit
-    mp_int_t i = MICROPY_FLOAT_C_FUN(trunc)(val);
-    return mp_obj_new_int(i);
+    int cl = fpclassify(val);
+    if (cl == FP_INFINITE) {
+        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OverflowError, "can't convert inf to int"));
+    } else if (cl == FP_NAN) {
+        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "can't convert NaN to int"));
+    } else {
+        mp_fp_as_int_class_t icl = mp_classify_fp_as_int(val);
+        if (icl == MP_FP_CLASS_FIT_SMALLINT) {
+            return MP_OBJ_NEW_SMALL_INT((mp_int_t)val);
+        } else {
+            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "float too big"));
+        }
+    }
 }
 #endif