Improve timers

Former-commit-id: 02985b13aec6ac4ce52952b9bc505e48ebbb94e6

src/core/iodev.rs

@@ -208,25 +208,25 @@ impl Bus for IoDevices {
                 io.timers[0].timer_data = value;
                 io.timers[0].initial_data = value;
             }
-            REG_TM0CNT_H => io.timers[0].timer_ctl.0 = value,
+            REG_TM0CNT_H => io.timers.write_timer_ctl(0, value),
 
             REG_TM1CNT_L => {
                 io.timers[1].timer_data = value;
                 io.timers[1].initial_data = value;
             }
-            REG_TM1CNT_H => io.timers[1].timer_ctl.0 = value,
+            REG_TM1CNT_H => io.timers.write_timer_ctl(1, value),
 
             REG_TM2CNT_L => {
                 io.timers[2].timer_data = value;
                 io.timers[2].initial_data = value;
             }
-            REG_TM2CNT_H => io.timers[2].timer_ctl.0 = value,
+            REG_TM2CNT_H => io.timers.write_timer_ctl(2, value),
 
             REG_TM3CNT_L => {
                 io.timers[3].timer_data = value;
                 io.timers[3].initial_data = value;
             }
-            REG_TM3CNT_H => io.timers[3].timer_ctl.0 = value,
+            REG_TM3CNT_H => io.timers.write_timer_ctl(3, value),
 
             DMA_BASE..=REG_DMA3CNT_H => {
                 let ofs = io_addr - DMA_BASE;

src/core/timer.rs

@@ -74,24 +74,43 @@ impl Timer {
 }
 
 #[derive(Debug)]
-pub struct Timers([Timer; 4]);
+pub struct Timers {
+    timers: [Timer; 4],
+    pub trace: bool,
+}
 
 impl std::ops::Index<usize> for Timers {
     type Output = Timer;
     fn index(&self, index: usize) -> &Self::Output {
-        &self.0[index]
+        &self.timers[index]
     }
 }
 
 impl std::ops::IndexMut<usize> for Timers {
     fn index_mut(&mut self, index: usize) -> &mut Self::Output {
-        &mut self.0[index]
+        &mut self.timers[index]
     }
 }
 
 impl Timers {
     pub fn new() -> Timers {
-        Timers([Timer::new(0), Timer::new(1), Timer::new(2), Timer::new(3)])
+        Timers {
+            timers: [Timer::new(0), Timer::new(1), Timer::new(2), Timer::new(3)],
+            trace: false,
+        }
+    }
+
+    pub fn write_timer_ctl(&mut self, id: usize, value: u16) {
+        let old_enabled = self[id].timer_ctl.enabled();
+        self[id].timer_ctl.0 = value;
+        let new_enabled = self[id].timer_ctl.enabled();
+        if self.trace && old_enabled != new_enabled {
+            println!(
+                "TMR{} {}",
+                id,
+                if new_enabled { "enabled" } else { "disabled" }
+            );
+        }
     }
 }
 
@@ -100,15 +119,20 @@ impl SyncedIoDevice for Timers {
         for i in 0..4 {
             if self[i].timer_ctl.enabled() && !self[i].timer_ctl.cascade() {
                 match self[i].add_cycles(cycles, irqs) {
-                    TimerAction::Overflow(num_overflows) => match i {
-                        3 => {}
-                        _ => {
-                            let next_i = i + 1;
-                            if self[next_i].timer_ctl.cascade() {
-                                self[next_i].add_cycles(num_overflows, irqs);
+                    TimerAction::Overflow(num_overflows) => {
+                        if self.trace {
+                            println!("TMR{} overflown!", i);
+                        }
+                        match i {
+                            3 => {}
+                            _ => {
+                                let next_i = i + 1;
+                                if self[next_i].timer_ctl.cascade() {
+                                    self[next_i].add_cycles(num_overflows, irqs);
+                                }
                             }
                         }
-                    },
+                    }
                     TimerAction::Increment => {}
                 }
             }

src/debugger/command.rs

@@ -203,7 +203,7 @@ impl Debugger {
                     println!("[*] dma tracing not implemented");
                 }
                 if flags.contains(TraceFlags::TRACE_TIMERS) {
-                    println!("[*] timers tracing not implemented");
+                    self.gba.sysbus.io.timers.trace = !self.gba.sysbus.io.timers.trace;
                 }
             }
         }