1 files changed, 67 insertions, 0 deletions
diff --git a/src/interrupts_timers.rs b/src/interrupts_timers.rs
new file mode 100644
index 0000000..c339ce8
--- /dev/null
+++ b/src/interrupts_timers.rs
@@ -0,0 +1,67 @@
+use crate::display::DisplayInterrupt;
+use crate::opcodes;
+use crate::state::{GBState, MemError};
+
+const TIMA_TIMER_SPEEDS: [u64; 4] = [1024, 16, 64, 256];
+
+impl GBState {
+    pub fn check_interrupts(&mut self) -> Result<(), MemError> {
+        if self.mem.ime {
+            let interrupts = self.mem.io[0x0f] & self.mem.interrupts_register & 0b11111;
+            for i in 0..5 {
+                if interrupts & (1 << i) != 0 {
+                    opcodes::push(self, self.cpu.pc)?;
+
+                    self.mem.ime = false;
+                    self.cpu.pc = 0x40 + (i << 3);
+                    self.mem.halt = false;
+
+                    self.mem.io[0x0f] &= !(1 << i);
+                    break;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    pub fn tima_timer(&mut self, c: u64) {
+        if self.mem.timer_enabled
+            && self.tima_cycles >= TIMA_TIMER_SPEEDS[self.mem.timer_speed as usize]
+        {
+            if self.mem.tima == 0xff {
+                self.mem.io[0x0f] |= 0b100;
+                self.mem.tima = self.mem.tma;
+            } else {
+                self.mem.tima += 1;
+            }
+            self.tima_cycles %= TIMA_TIMER_SPEEDS[self.mem.timer_speed as usize];
+        }
+        self.tima_cycles += c;
+    }
+
+    pub fn update_display_interrupts(&mut self, c: u64) {
+        let interrupt = self.mem.display.update_display(c);
+
+        match interrupt {
+            DisplayInterrupt::Vblank => {
+                self.mem.io[0x0f] |= 1;
+            }
+            DisplayInterrupt::Stat => {
+                self.mem.io[0xf] |= 2;
+            }
+            DisplayInterrupt::Both => {
+                self.mem.io[0xf] |= 3;
+            }
+            _ => {}
+        }
+    }
+
+    pub fn div_timer(&mut self, c: u64) {
+        if self.div_cycles >= 256 {
+            self.mem.div += 1;
+
+            self.div_cycles = 0;
+        }
+        self.div_cycles += c;
+    }
+}