From 7772fdbf0adf36d034e60b0c844ad8c14fe91644 Mon Sep 17 00:00:00 2001
From: remutro <84990500+remutro@users.noreply.github.com>
Date: Sun, 19 Jan 2025 12:22:06 -0500
Subject: [PATCH] [MD/32X] Force PAL region when (PAL) or (Europe) are in ROM
 name (#1781)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

There are numerous headers in Mega Drive & 32X games that are not
correct resulting in PAL games to run at 60Hz instead of 50Hz. This
corrects this issue by using the same technique the Atari 2600 core uses
which is to look for "(PAL)" or "(Europe)" in the ROM name which will
then force the game to run as a PAL game.

This also addresses the 32X game Shadow Squadron - Stellar Assault which
is supposed to be an NTSC-U and PAL game, but only has PAL in the header
so it could only run at 50Hz. This adds NTSC-U as an option (leaving PAL
as the default), but can be selected using the "Prefer US" boot option
so it can run at 60Hz.

Addresses issues:
https://github.com/ares-emulator/ares/issues/1066
https://github.com/ares-emulator/ares/issues/1067

And yes, I'm aware I submitted an additional commit cause I spelled
Assault wrong in the comment, and managed to spell it wrong again in the
commit message. 🤦‍♂️
---
 mia/medium/mega-32x.cpp   | 11 +++++++++++
 mia/medium/mega-drive.cpp |  4 ++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/mia/medium/mega-32x.cpp b/mia/medium/mega-32x.cpp
index c49a7d29eb..2ddc927980 100644
--- a/mia/medium/mega-32x.cpp
+++ b/mia/medium/mega-32x.cpp
@@ -143,6 +143,17 @@ auto Mega32X::analyze(vector<u8>& rom) -> string {
     regions.append("NTSC-J", "NTSC-U", "PAL");
   }
 
+  // FIFA Soccer 96 and Mortal Kombat II have an incorrect header, so force PAL based on name
+  if(location.ifind("(Europe)") || location.ifind("(PAL)")) {
+    regions.reset();
+    regions.append("PAL");
+  }
+
+  //Shadow Squadron - Stellar Assault is missing NTSC-U region in header
+  if(hash == "2f9b6017258fbb1c37d81df07c68d5255495d3bf76d9c7b680ff66bccf665750") {
+    regions.append("NTSC-U");
+  }
+
   string domesticName;
   domesticName.resize(48);
   memory::copy(domesticName.get(), &rom[0x0120], domesticName.size());
diff --git a/mia/medium/mega-drive.cpp b/mia/medium/mega-drive.cpp
index 44456714c2..d61ada7ee6 100644
--- a/mia/medium/mega-drive.cpp
+++ b/mia/medium/mega-drive.cpp
@@ -280,8 +280,8 @@ auto MegaDrive::analyzeRegion(vector<u8>& rom, string hash) -> void {
     regions.append("NTSC-J", "NTSC-U", "PAL");
   }
 
-  //Alisia Dragoon (Europe)
-  if(hash == "0930b77d0474e99c10690245cac12a6618b6c16420e3575379aba6e715ea797a") {
+  // Many PAL games have incorrect headers, so force PAL based on name
+  if(location.ifind("(Europe)") || location.ifind("(PAL)")) {
     regions.reset();
     regions.append("PAL");
   }