From 5fe3d2ef2e695a9d1353ebbe2022f76ccb0b316f Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Tue, 7 Feb 2023 09:51:11 +1100
Subject: [PATCH] parse cart header

---
 src/main.rs                 |  8 ++++----
 src/processor/memory/rom.rs | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 70b0ee4..29db173 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -100,8 +100,11 @@ fn main() {
         *v = args.verbose;
     }
 
+    let rom: ROM = ROM::load(fs::read(args.rom).expect("Could not load ROM"));
+    let bootrom: Vec<u8> = fs::read(args.bootrom).expect("Could not load BootROM");
+
     let mut window = Window::new(
-        "Gameboy",
+        format!("{}", rom.get_title()).as_str(),
         WIDTH * FACTOR,
         HEIGHT * FACTOR,
         WindowOptions::default(),
@@ -114,9 +117,6 @@ fn main() {
 
     window.topmost(true);
 
-    let rom: ROM = ROM::load(fs::read(args.rom).expect("Could not load ROM"));
-    let bootrom: Vec<u8> = fs::read(args.bootrom).expect("Could not load BootROM");
-
     let mut cpu = CPU::new(Memory::init(bootrom, args.run_bootrom, rom), window);
 
     if !args.run_bootrom {
diff --git a/src/processor/memory/rom.rs b/src/processor/memory/rom.rs
index 3040ca2..5715854 100644
--- a/src/processor/memory/rom.rs
+++ b/src/processor/memory/rom.rs
@@ -1,12 +1,42 @@
 use crate::processor::memory::Address;
+use std::str::from_utf8_unchecked;
+
+#[derive(Debug)]
+enum MBC {
+    ROM,
+    MBC1,
+}
 
 pub struct ROM {
+    title: String,
     data: Vec<u8>,
+    mbc: MBC,
 }
 
 impl ROM {
     pub fn load(data: Vec<u8>) -> Self {
-        Self { data }
+        let mut title_length = 0x143;
+        for i in 0x134..0x143 {
+            title_length = i;
+            if data[i] == 0x0 {
+                break;
+            }
+        }
+        let title = unsafe { from_utf8_unchecked(&data[0x134..title_length]).to_string() };
+        let _gbc_flag = data[0x143];
+        let _sgb_flag = data[0x146];
+        let _rom_size = data[0x148];
+        let _ram_size = data[0x149];
+        let mbc = match data[0x147] {
+            0x00 => MBC::ROM,
+            0x01 => MBC::MBC1,
+            _ => panic!("unimplemented mbc: {:#X}", data[0x147]),
+        };
+        Self { title, data, mbc }
+    }
+
+    pub fn get_title(&self) -> &String {
+        &self.title
     }
 
     pub(super) fn get(&self, address: Address) -> u8 {