Memory controller 1

pineman · Jul 12, 2024 · 60c9966 · 60c9966
1 parent e6d0e37
commit 60c9966
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Showing 5 changed files with 165 additions and 35 deletions.
diff --git a/fpt/src/lr35902.rs b/fpt/src/lr35902.rs
@@ -708,7 +708,6 @@ impl LR35902 {
         }
 
         let cartridge_type = self.mem8(0x147);
-        println!("cartridge type: {}", cartridge_type);
         match instruction.opcode {
             0x00 => {
                 // NOP

diff --git a/fpt/src/memory/cartridge.rs b/fpt/src/memory/cartridge.rs
@@ -1,5 +1,49 @@
-use crate::memory::{Address, MemoryRange};
+use std::cell::RefCell;
+use std::rc::Rc;
+
 use crate::memory::map;
+use crate::memory::{Address, MemoryRange};
+
+fn get_rom_size(tape: &[u8]) -> u8 {
+    tape[map::ROM_SIZE]
+}
+
+fn get_ram_size(tape: &[u8]) -> u8 {
+    tape[map::RAM_SIZE]
+}
+
+fn get_cartridge_type(tape: &[u8]) -> u8 {
+    tape[map::CARTRIDGE_FLAG]
+}
+
+fn convert_rom_size(rom_size: u8) -> usize {
+    match rom_size {
+        0x00 => 2,
+        0x01 => 4,
+        0x02 => 8,
+        0x03 => 16,
+        0x04 => 32,
+        0x05 => 64,
+        0x06 => 128,
+        0x07 => 256,
+        0x08 => 512,
+        0x52 => 72,
+        0x53 => 80,
+        0x54 => 96,
+        _ => panic!(),
+    }
+}
+
+fn convert_ram_size(ram_size: u8) -> u16 {
+    match ram_size {
+        0x00 => 0,
+        0x02 => 1,
+        0x03 => 4,
+        0x04 => 16,
+        0x05 => 8,
+        _ => panic!(),
+    }
+}
 
 pub trait Cartridge {
     fn read(&self, address: Address) -> u8;
@@ -56,7 +100,7 @@ impl Cartridge for EmptyCartridge {
         0xFF
     }
     fn write(&mut self, _address: Address, _value: u8) {}
-    
+
     fn read_range(&self, memory_range: MemoryRange) -> Vec<u8> {
         Vec::new()
     }
@@ -79,10 +123,105 @@ impl Cartridge for NoMbcCartridge {
         self.memory[address]
     }
     fn write(&mut self, address: Address, value: u8) {
-        self.memory[address] = value;
+        if map::EXT_RAM.contains(&address) {
+            self.memory[address] = value;
+        }
     }
 
     fn read_range(&self, memory_range: MemoryRange) -> Vec<u8> {
         self.memory[memory_range].to_vec()
     }
 }
+
+pub struct Mbc1Cartridge {
+    memory: Vec<u8>,
+    rom_banks: Vec<[u8; 0x4000]>,
+    ram_banks: Vec<[u8; 0x2000]>,
+    ext_ram_enabled: bool,
+    rom_bank_number: usize,
+    ram_bank_number: usize,
+}
+
+impl Mbc1Cartridge {
+    pub fn new(cartridge: &[u8]) -> Mbc1Cartridge {
+        let rom_size = dbg!(convert_rom_size(get_rom_size(cartridge)));
+        let ram_size = dbg!(convert_ram_size(get_ram_size(cartridge)));
+        let mut rom_banks = vec![[0; 0x4000]; dbg!(rom_size as usize)];
+        let mut ram_banks = vec![[0; 0x2000]; dbg!(ram_size as usize)];
+
+        // TODO: wtf is this initialization
+        for i in 0..rom_size {
+            for j in 0..0x4000 {
+                let i = i as usize;
+                let j = j as usize;
+                rom_banks[i][j] = cartridge[0x4000 * i + j];
+            }
+        }
+
+        for i in 0..ram_size {
+            for j in 0..0x2000 {
+                let i = i as usize;
+                let j = j as usize;
+                ram_banks[i][j] = cartridge[0x2000 * i + j];
+            }
+        }
+
+        Mbc1Cartridge {
+            memory: cartridge.to_vec(),
+            rom_banks,
+            ram_banks,
+            ext_ram_enabled: false,
+            rom_bank_number: 0,
+            ram_bank_number: 0,
+        }
+    }
+}
+
+impl Cartridge for Mbc1Cartridge {
+    fn read(&self, address: Address) -> u8 {
+        if map::EXT_RAM.contains(&address) && !self.ext_ram_enabled {
+            0 // TODO: check that disabled ram reads 0
+        } else if map::EXT_RAM.contains(&address) && self.ext_ram_enabled {
+            self.ram_banks[self.ram_bank_number as usize][address - map::EXT_RAM.start]
+        } else if map::ROM_BANK0.contains(&address) {
+            self.rom_banks[0][address - map::ROM_BANK0.start]
+        } else if map::ROM_BANK1.contains(&address) {
+            self.rom_banks[self.rom_bank_number as usize][address - map::ROM_BANK1.start]
+        } else {
+            self.memory[address]
+        }
+    }
+    fn write(&mut self, address: Address, value: u8) {
+        if (0x0000..0x2000).contains(&address) {
+            self.ext_ram_enabled = value & 0xF == 0xA;
+        } else if (0x2000..0x4000).contains(&address) {
+            // TODO: rom bank number upper bits
+            let rom_bank_number = value & 0x1F;
+            if rom_bank_number == 0 {
+                self.rom_bank_number = 1;
+            } else {
+                self.rom_bank_number = rom_bank_number as usize; // TODO: needs to be masked to log2(#banks)
+            }
+        } else if (0x4000..0x6000).contains(&address) {
+            let ram_bank_number = value & 0x3;
+            self.ram_bank_number = ram_bank_number as usize; // TODO: needs to be checked for number of ram
+                                                             // banks
+        } else if map::EXT_RAM.contains(&address) && self.ext_ram_enabled {
+            self.memory[address] = value;
+        }
+    }
+
+    fn read_range(&self, memory_range: MemoryRange) -> Vec<u8> {
+        self.memory[memory_range].to_vec()
+    }
+}
+
+pub fn create_memory_bank(cartridge_data: &[u8]) -> Rc<RefCell<dyn Cartridge>> {
+    let cartridge_type = get_cartridge_type(cartridge_data);
+
+    match dbg!(cartridge_type) {
+        0x00 => Rc::new(RefCell::new(NoMbcCartridge::new(cartridge_data))),
+        0x01 | 0x02 | 0x03 => Rc::new(RefCell::new(Mbc1Cartridge::new(cartridge_data))),
+        _ => panic!(),
+    }
+}
diff --git a/fpt/src/memory/map.rs b/fpt/src/memory/map.rs
@@ -2,7 +2,6 @@
 /// ```
 /// assert_eq!(fpt::memory::map::ROM_DATA.start, 0x0100);
 /// ```
-
 use super::{Address, MemoryRange};
 
 //-------------------------------------------------------------------------
@@ -19,7 +18,7 @@ pub const ROM_DATA: MemoryRange = 0x0100..0x0150;
 /// From cartridge, usually a fixed bank
 pub const ROM_BANK0: MemoryRange = 0x0000..0x4000;
 /// From cartridge, switchable bank via mapper (if any) pub const USER_PROGRAM: MemoryRange = 0x0000..0x8000;
-pub const ROM_BANK1: MemoryRange = 0x4000..0x8000; 
+pub const ROM_BANK1: MemoryRange = 0x4000..0x8000;
 
 /// Video RAM (8 KB) - In CGB mode, switchable bank 0/1
 pub const VRAM: MemoryRange = 0x8000..0xA000;

diff --git a/fpt/src/memory/memory.rs b/fpt/src/memory/memory.rs
@@ -1,11 +1,11 @@
 use std::cell::{Ref, RefCell, RefMut};
+use std::ops::DerefMut;
 use std::ops::Range;
 use std::rc::Rc;
-use std::ops::DerefMut;
 
 use crate::bw;
-use crate::memory::{Cartridge, EmptyCartridge, NoMbcCartridge};
 use crate::memory::map;
+use crate::memory::{create_memory_bank, Cartridge, EmptyCartridge, NoMbcCartridge};
 
 pub type Address = usize;
 pub type MemoryRange = Range<Address>;
@@ -93,7 +93,7 @@ impl Memory {
         self.bootrom_unloaded = true;
     }
 
-    pub fn bootrom_unloaded(& self) -> bool {
+    pub fn bootrom_unloaded(&self) -> bool {
         self.bootrom_unloaded
     }
 }
@@ -136,8 +136,8 @@ impl Bus {
     pub fn load_cartridge(&mut self, cartridge: &[u8]) {
         // TODO: load
         self.memory_mut()
-            .set_cartridge(Rc::new(RefCell::new(NoMbcCartridge::new(cartridge))));
-        
+            .set_cartridge(create_memory_bank(cartridge));
+
         //println!("title: {}", self.memory().cartridge().get_title());
         //println!("code: {}", self.memory().cartridge().get_manufacturer_code());
         //println!("new licensee code: {}", self.memory().cartridge().get_new_licensee_code());
@@ -156,35 +156,28 @@ impl Bus {
     pub fn read(&self, address: Address) -> u8 {
         if map::BOOTROM.contains(&address) && !self.memory().bootrom_unloaded() {
             self.memory().bootrom[address]
-        }
-        else if map::ROM_BANK0.contains(&address) {
+        } else if map::ROM_BANK0.contains(&address)
+            || map::ROM_BANK1.contains(&address)
+            || map::EXT_RAM.contains(&address)
+        {
             self.memory().cartridge().borrow().read(address)
-        }
-        else if map::ROM_BANK1.contains(&address) {
-            self.memory().cartridge().borrow().read(address)
-        }
-        else if map::EXT_RAM.contains(&address) {
-            self.memory().cartridge().borrow().read(address)
-        }
-        else if address == map::JOYP {
+        } else if address == map::JOYP {
             self.joyp()
         } else {
             self.memory().mem[address as Address]
         }
     }
 
     pub fn write(&mut self, address: Address, value: u8) {
-        if address <= 0x7fff {
-            panic!(
-                "{}",
-                format!("writing to rom, address: {}, value: {}", address, value)
-            );
-        }
-
-        if map::EXT_RAM.contains(&address) {
-            self.memory_mut().cartridge_mut().borrow_mut().write(address, value);
-        }
-        else {
+        if map::ROM_BANK0.contains(&address)
+            || map::ROM_BANK1.contains(&address)
+            || map::EXT_RAM.contains(&address)
+        {
+            self.memory_mut()
+                .cartridge_mut()
+                .borrow_mut()
+                .write(address, value);
+        } else {
             self.memory_mut().mem[address as Address] = value;
         }
     }

diff --git a/fpt/src/memory/mod.rs b/fpt/src/memory/mod.rs
@@ -1,8 +1,8 @@
 mod cartridge;
+pub mod map;
 mod mbc1;
 mod memory;
 mod memory_controller;
-pub mod map;
 
-pub use cartridge::{Cartridge, EmptyCartridge, NoMbcCartridge};
-pub use memory::{Bus, Buttons, Address, MemoryRange};
+pub use cartridge::{create_memory_bank, Cartridge, EmptyCartridge, NoMbcCartridge};
+pub use memory::{Address, Bus, Buttons, MemoryRange};