From 11178a49db67304bb82287e4c93ef4a36cf5edca Mon Sep 17 00:00:00 2001
From: DizzyEggg <jajkodizzy@wp.pl>
Date: Mon, 27 Jul 2020 12:27:35 +0200
Subject: [PATCH] Fix undefined behaviour in protect animation

gPlttBufferFaded[sprite->data[2] + ++i] = gPlttBufferFaded[sprite->data[2] + i + 1]

The above does NOT make it certain that i gets incremented before reading from the right side. Changed it, so the function always increments i first, then reads from pal buffer.
---
 src/battle_anim_effects_1.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/battle_anim_effects_1.c b/src/battle_anim_effects_1.c
index 516c58e55..f4769145d 100644
--- a/src/battle_anim_effects_1.c
+++ b/src/battle_anim_effects_1.c
@@ -3967,24 +3967,25 @@ static void AnimProtect(struct Sprite* sprite)
 
 static void AnimProtect_Step(struct Sprite *sprite)
 {
-    int a;
-    int i;
+    int i, savedPal;
     sprite->data[5] += 96;
     sprite->pos2.x = -(sprite->data[5] >> 8);
     if (++sprite->data[1] > 1)
     {
+        int id;
         sprite->data[1] = 0;
-        a = gPlttBufferFaded[sprite->data[2] + 1];
+        savedPal = gPlttBufferFaded[sprite->data[2] + 1];
         i = 0;
         do
         {
-            gPlttBufferFaded[sprite->data[2] + ++i] = gPlttBufferFaded[sprite->data[2] + i + 1];
+            id = sprite->data[2] + ++i;
+            gPlttBufferFaded[id] = gPlttBufferFaded[id + 1];
         } while (i < 6);
 
-        gPlttBufferFaded[sprite->data[2] + 7] = a;
+        gPlttBufferFaded[sprite->data[2] + 7] = savedPal;
     }
 
-    if (sprite->data[7] > 6 && sprite->data[0] >0 && ++sprite->data[6] > 1)
+    if (sprite->data[7] > 6 && sprite->data[0] > 0 && ++sprite->data[6] > 1)
     {
         sprite->data[6] = 0;
         sprite->data[7] -= 1;