basic emulator testing framework

Author: kirjavascript

tests/src/labels.rs

@@ -20,6 +20,29 @@ fn labels() -> &'static HashMap<String, u16> {
     })
 }
 
+fn addrs() -> &'static HashMap<u16, String> {
+    static LABELS: OnceLock<HashMap<u16, String>> = OnceLock::new();
+    LABELS.get_or_init(|| {
+        let text = include_str!("../../tetris.lbl");
+        let mut labels: HashMap<u16, String> = HashMap::new();
+
+        for line in text.lines() {
+            let parts: Vec<&str> = line.split_whitespace().collect();
+            if parts.len() >= 2 {
+                if let Ok(hex_value) = u16::from_str_radix(parts[1], 16) {
+                    labels.insert(hex_value, parts[2].to_string());
+                }
+            }
+        }
+
+        labels
+    })
+}
+
 pub fn get(label: &str) -> u16 {
     *labels().get(label).expect(&format!("label {} not found", label))
 }
+
+pub fn from_addr(addr: u16) -> Option<&'static String> {
+    addrs().get(&addr)
+}

tests/src/main.rs

@@ -1,14 +1,9 @@
-use rusticnes_core::nes::NesState;
-use rusticnes_core::cartridge;
-
 mod labels;
+mod util;
 
-fn main() {
-    let rom = include_bytes!("../../tetris.nes");
-    let mut emu = NesState::new(Box::new(cartridge::mapper_from_file(rom)).unwrap());
-
-    emu.registers.pc = labels::get(".addPushDownPoints");
+// tests
+mod pushdown;
 
-    // set pc
-    // set stackpointer to something absurd
+fn main() {
+    pushdown::test();
 }

tests/src/pushdown.rs

@@ -0,0 +1,31 @@
+// reference implementation - tested against the original game
+fn pushdown(pushdown: u8, score: u16) -> u16 {
+    let ones = score % 10;
+    let hundredths = score % 100;
+    let mut newscore = ones as u8 + (pushdown - 1);
+    if newscore & 0xF > 9 {
+        newscore += 6;
+    }
+
+    let low = (newscore & 0xF) as u16;
+    let high = ((newscore & 0xF0) / 16 * 10) as u16;
+
+    let mut newscore = high + (hundredths - ones);
+    let nextscore = newscore + low;
+
+    if nextscore <= 100 {
+        newscore = nextscore;
+    }
+
+    newscore + (score-hundredths) - score
+}
+
+use crate::{ labels, util };
+
+pub fn test() {
+    let mut emu = util::emulator(None);
+
+    emu.registers.pc = labels::get(".addPushDownPoints");
+
+    util::run_to_return(&mut emu);
+}

tests/src/util.rs

@@ -0,0 +1,37 @@
+use rusticnes_core::nes::NesState;
+use rusticnes_core::{ cartridge, opcodes, opcode_info };
+use crate::labels;
+
+pub fn emulator(rom: Option<&[u8]>) -> NesState {
+    let rom = rom.unwrap_or(include_bytes!("../../tetris.nes"));
+    let mut emu = NesState::new(Box::new(cartridge::mapper_from_file(rom)).unwrap());
+
+    emu.power_on();
+
+    emu
+}
+
+pub fn run_to_return(emu: &mut NesState) {
+    opcodes::push(emu, 0);
+    opcodes::push(emu, 0);
+
+    loop {
+        print_step(emu);
+
+        if emu.registers.pc < 3 {
+            break;
+        }
+    }
+}
+
+pub fn print_step(emu: &mut NesState) {
+    if let Some(label) = labels::from_addr(emu.registers.pc) {
+        println!("{}:", label);
+    }
+
+    print!("{:x} ", emu.registers.pc);
+
+    emu.step();
+
+    println!("{}", opcode_info::disassemble_instruction(emu.cpu.opcode, 0, 0).0);
+}