From 9b88965cabfa3d88ab94546e3e90a5a7bdbca9b5 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <musukarekai@gmail.com>
Date: Tue, 14 Jul 2020 21:43:03 -0500
Subject: [PATCH] Fix bug in Fx33 Opcode. Fx33 now works as intended.

---
 src/emu.rs  | 35 ++++++++++++-----------------------
 src/main.rs |  2 +-
 2 files changed, 13 insertions(+), 24 deletions(-)

diff --git a/src/emu.rs b/src/emu.rs
index 72666e2..7ae98de 100644
--- a/src/emu.rs
+++ b/src/emu.rs
@@ -400,15 +400,11 @@ impl Chip8 {
         // take tens digit and place it at I + 1
         // take ones digit and place it at I + 2
         let i = self.i as usize;
-        let mut digit = Self::digits(self.v[x as usize] as usize);
+        let digits: [u8; 3] = Self::to_digits(self.v[x as usize]);
 
-        let ones = digit.next().unwrap(); // Ther has to at least be a ones lol
-        let tens = digit.next().unwrap_or(0);
-        let hundreds = digit.next().unwrap_or(0);
-
-        self.memory[i] = hundreds as u8;
-        self.memory[i + 1] = tens as u8;
-        self.memory[i + 2] = ones as u8;
+        self.memory[i] = digits[2];
+        self.memory[i + 1] = digits[1];
+        self.memory[i + 2] = digits[0];
     }
 
     fn copy_from_vx_to_memory(&mut self, x: u8) {
@@ -425,23 +421,16 @@ impl Chip8 {
         }
     }
 
-    // https://stackoverflow.com/questions/41536479/how-do-i-split-an-integer-into-individual-digits
-    fn digits(mut num: usize) -> impl Iterator<Item = usize> {
-        let mut divisor = 1;
-        while num >= divisor * 10 {
-            divisor *= 10;
+    fn to_digits(num: u8) -> [u8; 3] {
+        let mut cpy = num.clone();
+        let mut digits = [0, 0, 0];
+
+        for digit in digits.iter_mut() {
+            *digit = cpy % 10;
+            cpy /= 10;
         }
 
-        std::iter::from_fn(move || {
-            if divisor == 0 {
-                None
-            } else {
-                let v = num / divisor;
-                num %= divisor;
-                divisor /= 10;
-                Some(v)
-            }
-        })
+        digits
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index 366ed3a..a80ae49 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,7 +21,7 @@ fn main() {
     let window = init_window(&event_loop);
     let mut pixels = init_pixels(&window);
 
-    let rom_path = Path::new("./games/ibm_logo.ch8");
+    let rom_path = Path::new("./games/test_opcode.ch8");
     chip8.load_rom(rom_path).expect("Unable to load ROM");
 
     event_loop.run(move |event, _, control_flow| {