added a state dumper for headless checks

src/main.rs

@@ -5,6 +5,7 @@ mod mapper;
 mod palette;
 mod render;
 mod ppu;
+mod dump;
 
 use crate::bus::{Bus, NesBus};
 use crate::cartridge::Cartridge;
@@ -17,6 +18,7 @@ fn main() {
     match args.len() {
         1 => run_nestest(),
         3 if args[1] == "blargg" => run_blargg(&args[2]),
+        3 if args[1] == "dbg" => run_dbg(&args[2]),
         2 => run_cart(&args[1]),
         _ => eprintln!("usage: rnes [<rom> | blargg <rom>]"),
     }
@@ -28,14 +30,14 @@ fn run_cart(path: &str) {
     let mut cpu = Cpu::new();
     cpu.reset(&mut bus);
     let mut renderer = PpmRenderer::new();
-    let frames: u32 = 60;
+    let frames: u32 = 180;
 
     for _ in 0..frames {
         while !bus.frame_done() {
             let cycles = cpu.step(&mut bus);
             bus.tick_ppu(cycles as u64);
+            if bus.take_nmi() { cpu.set_nmi(); }   // NMI fires when vblank hits, mid-frame
         }
-        if bus.take_nmi() { cpu.set_nmi(); }
         renderer.present(bus.framebuffer(), 256, 240);
         bus.begin_frame();
     }
@@ -70,3 +72,23 @@ fn run_nestest() {
         cpu.step(&mut bus);
     }
 }
+
+fn run_dbg(path: &str) {
+    let cart = Cartridge::from_file(path).unwrap();
+    let mut bus = NesBus::new(cart);
+    let mut cpu = Cpu::new();
+    cpu.reset(&mut bus);
+    let mut dumper = dump::Dumper::new();
+    let frames: u32 = 180;
+
+    for f in 0..frames {
+        while !bus.frame_done() {
+            let cycles = cpu.step(&mut bus);
+            bus.tick_ppu(cycles as u64);
+            if bus.take_nmi() { cpu.set_nmi(); }
+        }
+        dumper.snapshot(f, &bus, &cpu);
+        bus.begin_frame();
+    }
+    println!("wrote debug_out/ (state.txt + pctrace.txt), {frames} frames");
+}