py/modbuiltins: Implement abs() by dispatching to MP_UNARY_OP_ABS.

This allows user classes to implement __abs__ special method, and saves
code size (104 bytes for x86_64), even though during refactor, an issue
was fixed and few optimizations were made:

* abs() of minimum (negative) small int value is calculated properly.
* objint_longlong and objint_mpz avoid allocating new object is the
  argument is already non-negative.

1 files changed, 9 insertions, 21 deletions

diff --git a/py/objint_mpz.c b/py/objint_mpz.c
index 0e318b492..15aad1d4d 100644
--- a/py/objint_mpz.c
+++ b/py/objint_mpz.c
@@ -141,27 +141,6 @@ int mp_obj_int_sign(mp_obj_t self_in) {
     }
 }
 
-// This must handle int and bool types, and must raise a
-// TypeError if the argument is not integral
-mp_obj_t mp_obj_int_abs(mp_obj_t self_in) {
-    if (MP_OBJ_IS_TYPE(self_in, &mp_type_int)) {
-        mp_obj_int_t *self = MP_OBJ_TO_PTR(self_in);
-        mp_obj_int_t *self2 = mp_obj_int_new_mpz();
-        mpz_abs_inpl(&self2->mpz, &self->mpz);
-        return MP_OBJ_FROM_PTR(self2);
-    } else {
-        mp_int_t val = mp_obj_get_int(self_in);
-        if (val == MP_SMALL_INT_MIN) {
-            return mp_obj_new_int_from_ll(-val);
-        } else {
-            if (val < 0) {
-                val = -val;
-            }
-            return MP_OBJ_NEW_SMALL_INT(val);
-        }
-    }
-}
-
 mp_obj_t mp_obj_int_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
     mp_obj_int_t *o = MP_OBJ_TO_PTR(o_in);
     switch (op) {
@@ -170,6 +149,15 @@ mp_obj_t mp_obj_int_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
         case MP_UNARY_OP_POSITIVE: return o_in;
         case MP_UNARY_OP_NEGATIVE: { mp_obj_int_t *o2 = mp_obj_int_new_mpz(); mpz_neg_inpl(&o2->mpz, &o->mpz); return MP_OBJ_FROM_PTR(o2); }
         case MP_UNARY_OP_INVERT: { mp_obj_int_t *o2 = mp_obj_int_new_mpz(); mpz_not_inpl(&o2->mpz, &o->mpz); return MP_OBJ_FROM_PTR(o2); }
+        case MP_UNARY_OP_ABS: {
+            mp_obj_int_t *self = MP_OBJ_TO_PTR(o_in);
+            if (self->mpz.neg == 0) {
+                return o_in;
+            }
+            mp_obj_int_t *self2 = mp_obj_int_new_mpz();
+            mpz_abs_inpl(&self2->mpz, &self->mpz);
+            return MP_OBJ_FROM_PTR(self2);
+        }
         default: return MP_OBJ_NULL; // op not supported
     }
 }