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, 10 insertions, 24 deletions

diff --git a/py/objint_longlong.c b/py/objint_longlong.c
index ddfdae744..8d8ca1b2c 100644
--- a/py/objint_longlong.c
+++ b/py/objint_longlong.c
@@ -94,30 +94,6 @@ 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 = self_in;
-        self = mp_obj_new_int_from_ll(self->val);
-        if (self->val < 0) {
-            // TODO could overflow long long
-            self->val = -self->val;
-        }
-        return self;
-    } 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 = o_in;
     switch (op) {
@@ -130,6 +106,16 @@ 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: return mp_obj_new_int_from_ll(-o->val);
         case MP_UNARY_OP_INVERT: return mp_obj_new_int_from_ll(~o->val);
+        case MP_UNARY_OP_ABS: {
+            mp_obj_int_t *self = MP_OBJ_TO_PTR(o_in);
+            if (self->val >= 0) {
+                return o_in;
+            }
+            self = mp_obj_new_int_from_ll(self->val);
+            // TODO could overflow long long
+            self->val = -self->val;
+            return MP_OBJ_FROM_PTR(self);
+        }
         default: return MP_OBJ_NULL; // op not supported
     }
 }