Add savegame files

src/cartridge.rs

@@ -19,10 +19,11 @@ enum RamSize {
 
 pub struct Cartridge {
     mbc: Box<super::mbc::mbc::MBC>,
+    savefile: Option<String>,
 }
 
 impl Cartridge {
-    pub fn new(rom: Box<[u8]>) -> Cartridge {
+    pub fn new(rom: Box<[u8]>, save_file: Option<String>) -> Cartridge {
         let mbc_type: MemoryBankControllerType = match rom[0x0147] {
             0x00 | 0x08 ... 0x09 => MemoryBankControllerType::None,
             0x01 ... 0x03 => MemoryBankControllerType::MBC1,
@@ -54,12 +55,7 @@ impl Cartridge {
         println!("Rom size: {} banks", rom_banks);
         println!("Ram size: {:?}", ram_size);
 
-        let ram = match ram_size {
-            RamSize::None => vec![0u8; 0].into_boxed_slice(),
-            RamSize::Ram2KB => vec![0u8; 2048].into_boxed_slice(),
-            RamSize::Ram8KB => vec![0u8; 4 * 2048].into_boxed_slice(),
-            RamSize::Ram32KB => vec![0u8; 16 * 2048].into_boxed_slice(),
-        };
+        let ram = Cartridge::load_savefile(&save_file, ram_size);
 
         let mbc: Box<super::mbc::mbc::MBC> = match mbc_type {
             MemoryBankControllerType::None => Box::new(super::mbc::mbc::NoMBC::new(rom, ram)),
@@ -71,6 +67,39 @@ impl Cartridge {
 
         Cartridge {
             mbc: mbc,
+            savefile: save_file,
+        }
+    }
+
+    fn load_savefile(save_file: &Option<String>, ram_size: RamSize) -> Box<[u8]> {
+        let old_data;
+        let size = match ram_size {
+            RamSize::None => 0,
+            RamSize::Ram2KB => 2048,
+            RamSize::Ram8KB => 4 * 2048,
+            RamSize::Ram32KB => 16 * 2048,
+        };
+
+        if let &Some(ref filename) = save_file {
+            let data = super::read_file(&filename);
+            if let Ok(success) = data {
+                old_data = success
+            } else {
+                old_data = vec![0u8; size].into_boxed_slice();
+            }
+        } else {
+            old_data = vec![0u8; size].into_boxed_slice();
+        }
+
+        old_data
+    }
+
+    pub fn save(&self) {
+        if let &Some(ref fil) = &self.savefile {
+            self.mbc.dump_ram(fil);
+            println!("Ram dump updated.")
+        } else {
+            println!("Did not update ram dump");
         }
     }
 

src/interconnect.rs

@@ -59,13 +59,16 @@ pub struct Interconnect {
     joy_regular_keys: u8,
     joy_special_keys: u8,
     joy_switch: u8,
+
+    // Used for polling SDL events
+    cycles: u16,
 }
 
 impl Interconnect {
-    pub fn new(bios: Box<[u8]>, rom: Box<[u8]>) -> Interconnect {
+    pub fn new(bios: Box<[u8]>, rom: Box<[u8]>, save_file: Option<String>) -> Interconnect {
         Interconnect {
             bios: bios,
-            cartridge: cartridge::Cartridge::new(rom),
+            cartridge: cartridge::Cartridge::new(rom, save_file),
             ram: vec![0; WRAM_SIZE].into_boxed_slice(),
             hiram: vec![0; HIRAM_SIZE].into_boxed_slice(),
             wram_bank: 1,

src/main.rs

@@ -2,7 +2,9 @@
 // gameboy (color?)
 
 use std::path::Path;
+use std::io;
 use std::io::Read;
+use std::io::Write;
 use std::fs;
 use std::env;
 
@@ -17,23 +19,39 @@ mod mbc;
 
 
 fn main() {
-    let bios_path = env::args().nth(1).unwrap();
-    let rom_path = env::args().nth(2).unwrap();
-    let bios = read_rom(&bios_path);
-    let rom = read_rom(&rom_path);
+    let args: Vec<String> = env::args().collect();
+    if args.len() < 3 || args.len() > 4 {
+        println!("Usage: {} bios game [savefile]", args[0]);
+    } else {
+        let bios_path = &args[1];
+        let rom_path = &args[2];
+        let mut save_file: Option<String> = None;
+        if args.len() == 4 {
+            save_file = Some(args[3].clone());
+        }
 
-    // Now we need to execute commands
-    let interconnect = interconnect::Interconnect::new(bios, rom);
-    let mut cpu = cpu::CPU::new(interconnect);
+        let bios = read_file(&bios_path).unwrap();
+        let rom = read_file(&rom_path).unwrap();
 
-    loop {
-        cpu.run_instruction();
+        // Now we need to execute commands
+        let interconnect = interconnect::Interconnect::new(bios, rom, save_file);
+        let mut cpu = cpu::CPU::new(interconnect);
+
+        loop {
+            cpu.run();
+        }
     }
 }
 
-fn read_rom<P: AsRef<Path>>(rom_path: P) -> Box<[u8]> {
-    let mut file = fs::File::open(rom_path).unwrap();
+pub fn read_file<P: AsRef<Path>>(rom_path: P) -> Result<Box<[u8]>, io::Error> {
+    let mut file = try!(fs::File::open(rom_path));
     let mut buf = Vec::new();
-    file.read_to_end(&mut buf).expect("Reading file failed");
-    buf.into_boxed_slice()
+    try!(file.read_to_end(&mut buf));
+    Ok(buf.into_boxed_slice())
+}
+
+pub fn write_file<P: AsRef<Path>>(path: P, data: &Box<[u8]>) -> Result<(), io::Error> {
+    let mut file = try!(fs::File::create(path));
+    try!(file.write(&data));
+    Ok(())
 }

src/mbc/mbc.rs

@@ -1,6 +1,8 @@
 pub trait MBC {
     fn read_byte(&self, addr: u16) -> u8;
     fn write_byte(&mut self, addr: u16, val: u8);
+
+    fn dump_ram(&self, file: &String);
 }
 
 pub struct NoMBC {
@@ -10,7 +12,6 @@ pub struct NoMBC {
 
 impl NoMBC {
     pub fn new(rom: Box<[u8]>, ram: Box<[u8]>) -> NoMBC {
-
         NoMBC {
             rom: rom,
             ram: ram,
@@ -19,6 +20,10 @@ impl NoMBC {
 }
 
 impl MBC for NoMBC {
+    fn dump_ram(&self, file: &String){
+        super::super::write_file(&file, &self.ram).expect("Saving failed");
+    }
+
     fn write_byte(&mut self, addr: u16, val: u8) {
         println!("Writing not supported for cartridges without MBC. (Tried to set {:04X} to {:02X})", addr, val);
     }

src/mbc/mbc1.rs

@@ -43,6 +43,10 @@ impl MBC1 {
  }
 
 impl MBC for MBC1 {
+    fn dump_ram(&self, file: &String){
+        super::super::write_file(&file, &self.ram).expect("Saving failed");
+    }
+
     fn read_byte(&self, addr: u16) -> u8 {
         match addr {
             0x0000 ... 0x3FFF => self.rom[addr as usize],

src/mbc/mbc2.rs

@@ -23,6 +23,10 @@ impl MBC2 {
  }
 
 impl MBC for MBC2 {
+    fn dump_ram(&self, file: &String){
+        super::super::write_file(&file, &self.ram).expect("Saving failed");
+    }
+
     fn read_byte(&self, addr: u16) -> u8 {
         match addr {
             0x0000 ... 0x3FFF => self.rom[addr as usize],

src/mbc/mbc3.rs

@@ -29,6 +29,10 @@ impl MBC3 {
 }
 
 impl MBC for MBC3 {
+    fn dump_ram(&self, file: &String){
+        super::super::write_file(&file, &self.ram).expect("Saving failed");
+    }
+
     fn read_byte(&self, addr: u16) -> u8 {
         match addr {
             0x0000 ... 0x3FFF => self.rom[addr as usize],