From 418eb06e665db432cb24a09831ed23d0b05f2c4c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Janiszewski?=
 <janisozaur@users.noreply.github.com>
Date: Sat, 23 Jul 2016 22:52:28 +0200
Subject: [PATCH] Fix #3987: division by zero in vehicle update

Prevent division by zero by checking the value first.
---
 src/ride/vehicle.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/ride/vehicle.c b/src/ride/vehicle.c
index cb30487c7b..0a79256faf 100644
--- a/src/ride/vehicle.c
+++ b/src/ride/vehicle.c
@@ -8476,7 +8476,9 @@ loc_6DC23A:
 	regs.edx = vehicle->powered_acceleration;
 	regs.edx <<= 1;
 	regs.eax *= regs.edx;
-	regs.eax /= regs.ebx;
+	if (regs.ebx != 0) {
+		regs.eax /= regs.ebx;
+	}
 
 	if (vehicleEntry->flags_a & VEHICLE_ENTRY_FLAG_A_15) {
 		regs.eax *= 4;