py: Implement sys.maxsize, standard way to check platform "bitness".

Implementing it as a static constant is a bit peculiar and require cooperation
from long int implementation.

1 files changed, 20 insertions, 0 deletions

diff --git a/py/objint_mpz.c b/py/objint_mpz.c
index da02b1ea9..6e1c3c5a8 100644
--- a/py/objint_mpz.c
+++ b/py/objint_mpz.c
@@ -43,6 +43,26 @@
 
 #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_MPZ
 
+#if MICROPY_PY_SYS_MAXSIZE
+// Export value for sys.maxsize
+#define DIG_MASK ((1 << MPZ_DIG_SIZE) - 1)
+STATIC const mpz_dig_t maxsize_dig[MPZ_NUM_DIG_FOR_INT] = {
+    (INT_MAX >> MPZ_DIG_SIZE * 0) & DIG_MASK,
+    (INT_MAX >> MPZ_DIG_SIZE * 1) & DIG_MASK,
+    (INT_MAX >> MPZ_DIG_SIZE * 2) & DIG_MASK,
+    #if (INT_MAX >> MPZ_DIG_SIZE * 2) > DIG_MASK
+    (INT_MAX >> MPZ_DIG_SIZE * 3) & DIG_MASK,
+    (INT_MAX >> MPZ_DIG_SIZE * 4) & DIG_MASK,
+//    (INT_MAX >> MPZ_DIG_SIZE * 5) & DIG_MASK,
+    #endif
+};
+const mp_obj_int_t mp_maxsize_obj = {
+    {&mp_type_int},
+    {.fixed_dig = 1, .len = MPZ_NUM_DIG_FOR_INT, .alloc = MPZ_NUM_DIG_FOR_INT, .dig = (mpz_dig_t*)maxsize_dig}
+};
+#undef DIG_MASK
+#endif
+
 STATIC mp_obj_int_t *mp_obj_int_new_mpz(void) {
     mp_obj_int_t *o = m_new_obj(mp_obj_int_t);
     o->base.type = &mp_type_int;