Fixed a bug that caused interrupts to not be called

src/interrupts.rs

@@ -16,25 +16,28 @@ pub enum Interrupt {
 }
 
 impl GameBoy {
+    // TODO: Make this actually good
     pub(crate) fn execute_interrupts(&mut self) {
         if !self.flags.ime {
             return;
         }
 
         let stat = self.bus[STAT];
-        if stat.get_bit(6) && self.bus[LYC] == self.bus[LY] {
-            self.execute_interrupt(Interrupt::Stat);
-        }
-    }
 
-    fn execute_interrupt(&mut self, interrupt: Interrupt) {
-        // We don't want to call the same interrupt twice
-        if let Some(previous_interrupt) = &self.previous_interrupt {
-            if *previous_interrupt == interrupt {
-                return;
+        let is_lcd_enabled = stat.get_bit(6) && self.bus[LYC] == self.bus[LY];
+
+        // All this thing is done because an interrupt can only be triggered if it was
+        // previously off
+        if let Some(is_previous_lcd_enabled) = self.previous_lcd {
+            if is_lcd_enabled && !is_previous_lcd_enabled {
+                self.execute_interrupt(Interrupt::Stat);
             }
         }
 
+        self.previous_lcd = Some(is_lcd_enabled);
+    }
+
+    fn execute_interrupt(&mut self, interrupt: Interrupt) {
         // The bit corresponding to the correct interrupt, both in Interrupt Enable, and
         // Interrupt Flag bytes
         let if_bit: u8 = match interrupt {
@@ -56,7 +59,5 @@ impl GameBoy {
         let mut input_flags = self.bus[IF];
         input_flags.set_bit(if_bit, false);
         self.bus[IF] = input_flags;
-
-        self.previous_interrupt = Some(interrupt);
     }
 }

src/lib.rs

@@ -5,7 +5,6 @@ use common::merge_two_u8s_into_u16;
 use consts::bus::ROM_SIZE;
 use flags::Flags;
 use gpu::states::Gpu;
-use interrupts::Interrupt;
 use registers::Registers;
 
 mod bus;
@@ -26,9 +25,9 @@ pub struct GameBoy {
     pub flags: Flags,
     pub gpu: Gpu,
 
-    /// This is needed because we cannot fire the same interrupt twice in a row, so we
-    /// have to keep track of the last one
-    previous_interrupt: Option<Interrupt>,
+    // TODO: Remove this, to make the code better. Check `interrupts.rs` for more
+    // information on why this is needed
+    previous_lcd: Option<bool>,
 }
 
 impl GameBoy {
@@ -38,7 +37,7 @@ impl GameBoy {
             registers: Registers::new(),
             flags: Flags::new(),
             gpu: Gpu::new(),
-            previous_interrupt: None,
+            previous_lcd: None,
         })
     }
 
@@ -48,7 +47,7 @@ impl GameBoy {
             registers: Registers::new(),
             flags: Flags::new(),
             gpu: Gpu::new(),
-            previous_interrupt: None,
+            previous_lcd: None,
         }
     }