Memory observer

.gitignore

@@ -1,2 +1,3 @@
 /target
 /roms
+/logs

core/src/cpu/disassembler.rs

@@ -1,7 +1,7 @@
 use crate::cpu::op::AddressingMode::*;
 use crate::cpu::op::{AddressingMode, Instruction};
 use crate::cpu::Cpu;
-use simplelog::debug;
+use simplelog::{trace};
 
 impl Cpu {
     pub fn disassemble_next_instr(&self) {
@@ -12,7 +12,7 @@ impl Cpu {
         let operation = instr.op().to_string();
         let addr_mode = self.disassemble_addr_mode(instr.addr_mode(), registers.pc);
 
-        debug!(
+        trace!(
             "{:#04X} - ${:04X} {} {}\tA {:#04X}, X {:#04X}, Y {:#04X}, SP: {:#04X}, F: {:#04X}",
             op_code,
             registers.pc,
@@ -27,7 +27,7 @@ impl Cpu {
     }
 
     fn disassemble_addr_mode(&self, addr_mode: AddressingMode, pc: u16) -> String {
-        let word_peek = self.memory_bus.borrow().get_word(pc);
+        let word_peek = self.memory_bus.borrow().get_word(pc + 1);
         let byte_peek = (word_peek & 0xFF) as u8;
 
         match addr_mode {
@@ -40,10 +40,13 @@ impl Cpu {
             IND => format!("(${:04X})", word_peek),
             IDX => format!("(${:04X},x)", word_peek),
             IDY => format!("(${:04X}),y", word_peek),
-            REL => format!("#${:04X}", word_peek),
+            REL => format!(
+                "${:04X}",
+                (pc + 2).wrapping_add_signed(byte_peek as i8 as i16)
+            ),
             ACC => String::from('A'),
             IMP => String::from("I"),
-            IMM => format!("{:04X}", byte_peek),
+            IMM => format!("#${:02X}", byte_peek),
         }
     }
 }

core/src/cpu/op.rs

@@ -260,16 +260,10 @@ impl Cpu {
 
     /// label - PC + byte
     fn operand_addr_rel(&mut self) -> u16 {
+        let offset = self.program_get_next_byte() as u8;
         let base_addr = self.registers.pc;
-        let offset = self.program_get_next_byte() as u16;
 
-        // The offset is signed
-        let positive_offset = offset & 0x7F;
-        if offset & 0x80 > 0 {
-            base_addr.wrapping_sub(positive_offset)
-        } else {
-            base_addr.wrapping_add(positive_offset)
-        }
+        base_addr.wrapping_add_signed(offset as i8 as i16)
     }
 }
 

core/src/lib.rs

@@ -8,4 +8,4 @@ mod ppu;
 pub trait Clock {
     /// Run a clock cycle
     fn cycle(&mut self);
-}
+}

core/src/memory.rs

@@ -1,5 +1,7 @@
-use simplelog::warn;
+use std::cell::RefCell;
 use crate::mappers::Mapper;
+use simplelog::warn;
+use std::rc::{Weak};
 
 const MEMORY_MAX_ADDR: u16 = 0xFFFF;
 const PPU_MAX_ADDR: u16 = 0x4000;
@@ -12,12 +14,18 @@ const RAM_MAX_ADDR: u16 = 0x2000;
 pub struct MemoryBus {
     mapper: Option<Box<dyn Mapper>>,
     ram: [u8; RAM_SIZE],
+
+    observers: Vec<Weak<RefCell<dyn MemoryObserver>>>,
 }
 
 impl MemoryBus {
     pub fn new() -> Self {
         let ram = [0; RAM_SIZE];
-        Self { mapper: None, ram }
+        Self {
+            mapper: None,
+            ram,
+            observers: vec![],
+        }
     }
 
     /// Register a mapper in the memory bus, simulates plugging in a cartridge.
@@ -51,8 +59,11 @@ impl MemoryBus {
             let prg_addr = addr - CARTRIDGE_RAM_MAX_ADDR;
 
             if self.mapper.is_none() {
-                warn!("Tried to read memory address {} before setting a mapper", addr);
-                return 0
+                warn!(
+                    "Tried to read memory address {} before setting a mapper",
+                    addr
+                );
+                return 0;
             }
 
             let mapper = self.mapper.as_ref().unwrap();
@@ -94,5 +105,29 @@ impl MemoryBus {
             // Cannot write to ROM
             assert!(false);
         }
+
+        // Notify the observers
+        for observer in self.observers.iter() {
+            match observer.upgrade() {
+                None => {}
+                Some(rc) => rc.borrow_mut().notify_mem_byte_updated(addr, value)
+            }
+        }
+    }
+    
+    pub fn register_observer(&mut self, observer: Weak<RefCell<dyn MemoryObserver>>) {
+        self.observers.push(observer);
     }
 }
+
+// pub type MemoryObserver = impl Fn(u16, u8) -> ();
+
+// A memory observer. Will be notified when a byte was modified in memory.
+pub trait MemoryObserver {
+    /// Called when a byte was updated in the memory bus.
+    ///
+    /// # Arguments
+    ///  * addr - The address of the byte
+    ///  * value - The updated value
+    fn notify_mem_byte_updated(&mut self, addr: u16, value: u8);
+}

core/src/ppu/mod.rs

@@ -1,7 +1,8 @@
-use crate::memory::MemoryBus;
+use crate::memory::{MemoryBus, MemoryObserver};
 use crate::Clock;
 use std::cell::RefCell;
 use std::rc::Rc;
+use simplelog::info;
 
 pub struct Ppu {
     memory_bus: Rc<RefCell<MemoryBus>>,
@@ -9,7 +10,17 @@ pub struct Ppu {
 
 impl Ppu {
     pub fn new(memory_bus: Rc<RefCell<MemoryBus>>) -> Self {
-        Self { memory_bus }
+        Self { memory_bus: memory_bus.clone() }
+    }
+    
+    fn set_register(&self, addr: u16, value: u8) {
+        
+    }
+}
+
+impl MemoryObserver for Ppu {
+    fn notify_mem_byte_updated(&mut self, addr: u16, value: u8) {
+        info!("MemChange: {:#04x} -> {:#02x}", addr, value);
     }
 }
 

core/src/system.rs

@@ -19,15 +19,18 @@ const REFRESH_RATE: usize = 60; // 60 Hz
 pub struct System {
     cpu: Cpu,
     memory_bus: Rc<RefCell<MemoryBus>>,
-    ppu: Ppu
+    ppu: Rc<RefCell<Ppu>>
 }
 
 impl System {
     pub fn new() -> Self {
         let memory_bus = Rc::new(RefCell::new(MemoryBus::new()));
         let cpu = Cpu::new(Rc::clone(&memory_bus));
-        let ppu = Ppu::new(Rc::clone(&memory_bus));
-
+        let ppu = Rc::new(RefCell::new(Ppu::new(Rc::clone(&memory_bus))));
+        
+        let weak_ppu = Rc::downgrade(&ppu);
+        memory_bus.borrow_mut().register_observer(weak_ppu);
+        
         Self { cpu, memory_bus, ppu }
     }
 
@@ -49,7 +52,7 @@ impl Clock for System {
             self.cpu.cycle();
 
             for _ppu_cycle in 0usize..PPU_CYCLE_PER_REFRESH {
-                self.ppu.cycle();
+                self.ppu.borrow_mut().cycle();
             }
         }
     }

ui/src/main.rs

@@ -1,18 +1,26 @@
-use std::thread::sleep;
-use std::time::Duration;
 use core::system::System;
 use core::Clock;
 use simplelog::*;
+use std::fs::File;
+use std::thread::sleep;
+use std::time::Duration;
 
 const ROM_PATH: &'static str = "./roms/dk.nes";
 
 fn main() {
-    CombinedLogger::init(vec![TermLogger::new(
-        LevelFilter::Debug,
-        Config::default(),
-        TerminalMode::Mixed,
-        ColorChoice::Auto,
-    )])
+    CombinedLogger::init(vec![
+        TermLogger::new(
+            LevelFilter::Info,
+            Config::default(),
+            TerminalMode::Mixed,
+            ColorChoice::Auto,
+        ),
+        WriteLogger::new(
+            LevelFilter::Debug,
+            Config::default(),
+            File::create("./logs/latest.log").unwrap(),
+        ),
+    ])
     .unwrap();
 
     let mut system = System::new();