input handling

src/processor/gpu.rs

@@ -248,12 +248,12 @@ impl CPU {
     }
 
     fn enter_vblank(&mut self, lcdc: &LCDC) {
+        self.memory.update_pressed_keys(self.window.get_keys());
         self.gpu.mode = DrawMode::VBlank;
         if lcdc.enable {
             self.render_window();
             self.memory.set(0xFF0F, set_bit(self.memory.get(0xFF0F), 0));
         }
-        // println!("lcdc: {:#?}", lcdc);
     }
 
     fn exit_vblank(&mut self) {

src/processor/memory.rs

@@ -1,10 +1,84 @@
 use std::io::{stdout, Write};
 
+use minifb::Key;
+
 use crate::verbose_println;
 
+use super::{clear_bit, get_bit};
+
 pub(crate) type Address = u16;
 pub(crate) type ROM = Vec<u8>;
 
+enum JoypadBank {
+    Action,
+    Direction,
+}
+
+struct Joypad {
+    bank_sel: JoypadBank,
+    down: bool,
+    up: bool,
+    left: bool,
+    right: bool,
+    start: bool,
+    select: bool,
+    b: bool,
+    a: bool,
+}
+
+impl Joypad {
+    fn as_register(&self) -> u8 {
+        let mut reg = 0xFF;
+        match self.bank_sel {
+            JoypadBank::Action => {
+                if self.start {
+                    reg = clear_bit(reg, 3);
+                }
+                if self.select {
+                    reg = clear_bit(reg, 2);
+                }
+                if self.b {
+                    reg = clear_bit(reg, 1);
+                }
+                if self.a {
+                    reg = clear_bit(reg, 0);
+                }
+            }
+            JoypadBank::Direction => {
+                if self.down {
+                    reg = clear_bit(reg, 3);
+                }
+                if self.up {
+                    reg = clear_bit(reg, 2);
+                }
+                if self.left {
+                    reg = clear_bit(reg, 1);
+                }
+                if self.right {
+                    reg = clear_bit(reg, 0);
+                }
+            }
+        }
+        reg
+    }
+}
+
+impl Default for Joypad {
+    fn default() -> Self {
+        Self {
+            bank_sel: JoypadBank::Action,
+            down: false,
+            up: false,
+            left: false,
+            right: false,
+            start: false,
+            select: false,
+            b: false,
+            a: false,
+        }
+    }
+}
+
 #[allow(dead_code)]
 pub struct Memory {
     pub(super) bootrom: ROM,
@@ -20,6 +94,7 @@ pub struct Memory {
     pub(super) ime_scheduled: u8,
     pub(super) io: [u8; 76],
     pub(super) user_mode: bool,
+    joypad: Joypad,
 }
 
 impl Memory {
@@ -38,6 +113,7 @@ impl Memory {
             ime_scheduled: 0x0,
             io: [0xFF; 76],
             user_mode: false,
+            joypad: Joypad::default(),
         }
     }
 
@@ -66,7 +142,7 @@ impl Memory {
                 return self.oam[(address - 0xFE00) as usize];
             }
             0xFEA0..0xFF00 => {
-                return 0x0;
+                return 0xFF;
             }
             0xFF00..0xFF4C => self.get_io(address),
             0xFF4C..0xFF80 => {
@@ -133,7 +209,7 @@ impl Memory {
 
     fn get_io(&self, address: Address) -> u8 {
         if address == 0xFF00 {
-            return 0xFF;
+            return self.joypad.as_register();
         }
         return self.io[(address - 0xFF00) as usize];
     }
@@ -153,6 +229,12 @@ impl Memory {
                 0xFF04 => self.io[addr_l] = 0,
                 0xFF00 => {
                     // joypad
+                    if !get_bit(data, 5) {
+                        self.joypad.bank_sel = JoypadBank::Action
+                    }
+                    if !get_bit(data, 4) {
+                        self.joypad.bank_sel = JoypadBank::Direction
+                    }
                 }
                 0xFF11 | 0xFF14 | 0xFF16 | 0xFF19 | 0xFF1E | 0xFF23 | 0xFF26 => {
                     // sound
@@ -176,4 +258,15 @@ impl Memory {
             }
         }
     }
+
+    pub fn update_pressed_keys(&mut self, keys: Vec<Key>) {
+        self.joypad.down = keys.contains(&Key::Down) || keys.contains(&Key::S);
+        self.joypad.up = keys.contains(&Key::Up) || keys.contains(&Key::W);
+        self.joypad.left = keys.contains(&Key::Left) || keys.contains(&Key::A);
+        self.joypad.right = keys.contains(&Key::Right) || keys.contains(&Key::D);
+        self.joypad.start = keys.contains(&Key::Equal);
+        self.joypad.select = keys.contains(&Key::Minus);
+        self.joypad.a = keys.contains(&Key::Apostrophe);
+        self.joypad.b = keys.contains(&Key::Semicolon);
+    }
 }