From 2faec6a4fbd444c1396586fa3b00cf1fb73c2530 Mon Sep 17 00:00:00 2001
From: Jorge Aparicio <japaricious@gmail.com>
Date: Mon, 13 Mar 2017 20:40:44 -0500
Subject: [PATCH] fix debug assertion in modsi3 / moddi3

fixes #151
this fix is very similar to #149
---
 src/int/sdiv.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/int/sdiv.rs b/src/int/sdiv.rs
index 7f30eaf..1906560 100644
--- a/src/int/sdiv.rs
+++ b/src/int/sdiv.rs
@@ -33,9 +33,10 @@ macro_rules! mod_ {
         #[cfg_attr(not(test), no_mangle)]
         pub extern "C" fn $intrinsic(a: $ty, b: $ty) -> $tyret {
             let s = b >> (<$ty>::bits() - 1);
-            let b = (b ^ s) - s;
+            // NOTE(wrapping_sub) see comment in the `div` macro
+            let b = (b ^ s).wrapping_sub(s);
             let s = a >> (<$ty>::bits() - 1);
-            let a = (a ^ s) - s;
+            let a = (a ^ s).wrapping_sub(s);
 
             let r = urem!(a as $uty, b as $uty);
             ($conv)((r as $ty ^ s) - s)