From 04552ff71b6c722b21597d93481f024c72457cef Mon Sep 17 00:00:00 2001
From: Damien George
Date: Tue, 25 Jul 2017 11:49:22 +1000
Subject: py: Implement raising a big-int to a negative power.

Before this patch raising a big-int to a negative power would just return
0.  Now it returns a floating-point number with the correct value.
---
 py/objint_longlong.c | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'py/objint_longlong.c')

diff --git a/py/objint_longlong.c b/py/objint_longlong.c
index eb80407bc..1d184a7dc 100644
--- a/py/objint_longlong.c
+++ b/py/objint_longlong.c
@@ -191,6 +191,13 @@ mp_obj_t mp_obj_int_binary_op(mp_uint_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
 
         case MP_BINARY_OP_POWER:
         case MP_BINARY_OP_INPLACE_POWER: {
+            if (rhs_val < 0) {
+                #if MICROPY_PY_BUILTINS_FLOAT
+                return mp_obj_float_binary_op(op, lhs_val, rhs_in);
+                #else
+                mp_raise_ValueError("negative power with no float support");
+                #endif
+            }
             long long ans = 1;
             while (rhs_val > 0) {
                 if (rhs_val & 1) {
-- 
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