From 38a95088e8278e8a2b6c50d7f8a7e187819de449 Mon Sep 17 00:00:00 2001
From: gm-matthew <108370479+gm-matthew@users.noreply.github.com>
Date: Mon, 28 Aug 2023 03:12:43 +0100
Subject: [PATCH] Prevent "ROLLING START" scrolling glitch in Scud Race There
 is a quirk of the tilegen chip that causes this glitch not to occur on real
 hardware, but we can't be sure what it is without testing Much easier to just
 patch all the Scud Race ROM sets

---
 Config/Games.xml | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Config/Games.xml b/Config/Games.xml
index 411001a..82ec982 100644
--- a/Config/Games.xml
+++ b/Config/Games.xml
@@ -1443,6 +1443,10 @@
       </inputs>
     </hardware>
     <roms>
+      <patches>
+        <!-- Prevent "rolling start" scrolling glitch -->
+        <patch region="crom" bits="32" offset="0x14BDB8" value="0x20B201E0" />
+      </patches>
       <region name="crom" stride="8" chunk_size="2" byte_swap="true">
         <file offset="0" name="epr-19691.20" crc32="0x83523B89" />
         <file offset="2" name="epr-19690.19" crc32="0x25F007FE" />
@@ -1531,6 +1535,8 @@
       <patches>
         <!-- Secret debug menu -->
         <patch region="crom" bits="32" offset="0x199DE8" value="0x00050208" />
+        <!-- Prevent "rolling start" scrolling glitch -->
+        <patch region="crom" bits="32" offset="0x14BDF4" value="0x20B201E0" />
       </patches>
       <region name="crom" stride="8" chunk_size="2" byte_swap="true">
         <file offset="0" name="epr-19734.20" crc32="0xBE897336" />
@@ -1563,6 +1569,10 @@
       </inputs>
     </hardware>
     <roms>
+      <patches>
+        <!-- Prevent "rolling start" scrolling glitch -->
+        <patch region="crom" bits="32" offset="0x146350" value="0x20B201E0" />
+      </patches>
       <region name="crom" stride="8" chunk_size="2" byte_swap="true">
         <file offset="0" name="epr-19607a.20" crc32="0x24301A12" />
         <file offset="2" name="epr-19608a.19" crc32="0x1426160E" />
@@ -1636,6 +1646,10 @@
       </inputs>
     </hardware>
     <roms>
+      <patches>
+        <!-- Prevent "rolling start" scrolling glitch -->
+        <patch region="crom" bits="32" offset="0x14E3F0" value="0x20B201E0" />
+      </patches>
       <region name="crom" stride="8" chunk_size="2" byte_swap="true">
         <file offset="0" name="epr-20095a.20" crc32="0x58C7E393" />
         <file offset="2" name="epr-20094a.19" crc32="0xDBF17A43" />
@@ -1684,6 +1698,10 @@
       </inputs>
     </hardware>
     <roms>
+      <patches>
+        <!-- Prevent "rolling start" scrolling glitch -->
+        <patch region="crom" bits="32" offset="0x14E014" value="0x20B201E0" />
+      </patches>
       <region name="crom" stride="8" chunk_size="2" byte_swap="true">
         <file offset="0" name="epr-20095.20" crc32="0x44467BC1" />
         <file offset="2" name="epr-20094.19" crc32="0x299B6257" />