From 66b0e4af3560342cd1f65aefb9aabd4dc6b0498b Mon Sep 17 00:00:00 2001
From: Tomusdrw <tomusdrw@gmail.com>
Date: Fri, 15 Jan 2016 01:48:53 +0100
Subject: [PATCH] Using overflowing operations

---
 src/evm/interpreter.rs | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/evm/interpreter.rs b/src/evm/interpreter.rs
index 08bca2ed8..1d81eeede 100644
--- a/src/evm/interpreter.rs
+++ b/src/evm/interpreter.rs
@@ -696,23 +696,27 @@ impl Interpreter {
 			instructions::ADD => {
 				let a = stack.pop_back();
 				let b = stack.pop_back();
-				stack.push(a + b);
+				let (c, _overflow) = a.overflowing_add(a, b);
+				stack.push(c);
 			},
 			instructions::MUL => {
 				let a = stack.pop_back();
 				let b = stack.pop_back();
-				stack.push(a * b);
+				let (c, _overflow) = a.overflowing_mul(a, b);
+				stack.push(c);
 			},
 			instructions::SUB => {
 				let a = stack.pop_back();
 				let b = stack.pop_back();
-				stack.push(a - b);
+				let (c, _overflow) = a.overflowing_sub(a, b);
+				stack.push(c);
 			},
 			instructions::DIV => {
 				let a = stack.pop_back();
 				let b = stack.pop_back();
 				stack.push(if !self.is_zero(&b) {
-					a / b 
+					let (c, _overflow) = a.overflowing_div(a, b);
+					c
 				} else {
 					U256::zero()
 				});
@@ -721,7 +725,8 @@ impl Interpreter {
 				let a = stack.pop_back();
 				let b = stack.pop_back();
 				stack.push(if !self.is_zero(&b) {
-					a % b 
+					let (c, _overflow) = a.overflowing_rem(a, b);
+					c
 				} else {
 					U256::zero()
 				});