From a03d23097b3b0b2984ba610fb8cd678297dd2197 Mon Sep 17 00:00:00 2001
From: Lauchmelder <robert.altner11@gmail.com>
Date: Tue, 23 Aug 2022 19:01:26 +0200
Subject: [PATCH] initial commit

---
 .gitignore  |  2 ++
 Cargo.lock  |  7 +++++++
 Cargo.toml  |  8 ++++++++
 src/bus.rs  | 43 ++++++++++++++++++++++++++++++++++++++++
 src/cpu.rs  | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.rs | 10 ++++++++++
 src/nes.rs  | 34 ++++++++++++++++++++++++++++++++
 7 files changed, 161 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Cargo.lock
 create mode 100644 Cargo.toml
 create mode 100644 src/bus.rs
 create mode 100644 src/cpu.rs
 create mode 100644 src/main.rs
 create mode 100644 src/nes.rs

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a221ac1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+target/
+.vscode/
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..921a7e1
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "rusty-nes"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..be986c3
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "rusty-nes"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/bus.rs b/src/bus.rs
new file mode 100644
index 0000000..6d7fa20
--- /dev/null
+++ b/src/bus.rs
@@ -0,0 +1,43 @@
+use std::cell::RefCell;
+use std::rc::{Rc, Weak};
+
+use crate::cpu::CPU;
+
+pub struct Bus
+{
+	cpu: Weak<RefCell<CPU>>,
+
+	ram: Vec<u8>
+}
+
+impl Bus 
+{
+	pub fn new() -> Bus 
+	{
+		Bus 
+		{
+			cpu: Weak::new(),
+			ram: vec![0; 0x800]
+		}
+	}
+
+	pub fn run(&self)
+	{
+		let cpu = self.cpu.upgrade().unwrap();
+
+		loop
+		{
+			cpu.borrow_mut().execute();
+		}
+	}
+
+	pub fn attach_cpu(&mut self, cpu: &Rc<RefCell<CPU>>)
+	{	
+		self.cpu = Rc::downgrade(cpu);
+	}
+
+	pub fn read_cpu(&self, addr: u16) -> u8 
+	{
+		self.ram[addr as usize]
+	}
+}
\ No newline at end of file
diff --git a/src/cpu.rs b/src/cpu.rs
new file mode 100644
index 0000000..e6dfd3a
--- /dev/null
+++ b/src/cpu.rs
@@ -0,0 +1,57 @@
+use std::cell::RefCell;
+use std::rc::{Rc, Weak};
+
+use crate::bus::Bus;
+
+pub struct CPU
+{
+	acc: u8,
+	x: u8,
+	y: u8,
+	p: u8,
+	sp: u8,
+
+	pc: u16,
+
+	bus: Weak<RefCell<Bus>>
+}
+
+impl CPU 
+{
+	pub fn new(bus: &Rc<RefCell<Bus>>) -> CPU 
+	{
+		CPU {
+			acc: 0,
+			x: 0,
+			y: 0,
+			p: 0,
+			sp: 0,
+
+			pc: 0,
+
+			bus: Rc::downgrade(bus)
+		}
+	}
+
+	pub fn powerup(&mut self)
+	{
+		self.p = 0x34;
+
+		self.acc = 0;
+		self.x = 0;
+		self.y = 0;
+		self.sp = 0xFD;
+	}
+
+	pub fn execute(&mut self)
+	{
+		let bus = self.bus.upgrade().unwrap();
+		let opcode: u8 = bus.borrow().read_cpu(self.pc);
+		self.pc += 1;
+
+		match (opcode)
+		{
+			_ => panic!("Unimplemented opcode {}", opcode)
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..f2fa933
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,10 @@
+mod nes;
+mod bus;
+mod cpu;
+
+use nes::NES;
+
+fn main() {
+    let nes = NES::new();
+    nes.powerup();
+}
diff --git a/src/nes.rs b/src/nes.rs
new file mode 100644
index 0000000..5395cdd
--- /dev/null
+++ b/src/nes.rs
@@ -0,0 +1,34 @@
+use std::cell::RefCell;
+use std::rc::Rc;
+use crate::bus::Bus;
+use crate::cpu::CPU;
+
+pub struct NES
+{
+	bus: Rc<RefCell<Bus>>,
+	cpu: Rc<RefCell<CPU>>
+}
+
+impl NES
+{
+	pub fn new() -> NES 
+	{
+		let bus: Rc<RefCell<Bus>> = Rc::new(RefCell::new(Bus::new()));
+		let cpu: Rc<RefCell<CPU>> = Rc::new(RefCell::new(CPU::new(&bus)));
+
+		bus.borrow_mut().attach_cpu(&cpu);
+
+		NES 
+		{
+			bus: bus,
+			cpu: cpu
+		}
+	}
+
+	pub fn powerup(&self)
+	{
+		self.cpu.borrow_mut().powerup();
+
+		self.bus.borrow().run();
+	}
+}
\ No newline at end of file