From ae6ec26b6849eca93ffb4afde446e08074d73599 Mon Sep 17 00:00:00 2001
From: LLeny <LLeny@users.noreply.github.com>
Date: Sun, 15 Dec 2024 16:33:34 +0800
Subject: [PATCH] Linked timer as Option<NonZeroU8>

---
 src/mikey/timers/audio_channel_timer.rs | 6 +++---
 src/mikey/timers/base_timer.rs          | 6 +++---
 src/mikey/timers/mod.rs                 | 7 ++++---
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/mikey/timers/audio_channel_timer.rs b/src/mikey/timers/audio_channel_timer.rs
index ac5037c..575ab85 100644
--- a/src/mikey/timers/audio_channel_timer.rs
+++ b/src/mikey/timers/audio_channel_timer.rs
@@ -16,7 +16,7 @@ pub struct AudioChannelTimer {
     feedback: u8,
     shift_register: u8,
     output: i8,
-    linked_timer: Option<usize>,
+    linked_timer: Option<NonZeroU8>,
     is_linked: bool,
     count_enabled: bool,
     reload_enabled: bool,
@@ -24,7 +24,7 @@ pub struct AudioChannelTimer {
 }
 
 impl AudioChannelTimer{
-    pub fn new(id: u8, linked_timer: Option<usize>) -> Self {
+    pub fn new(id: u8, linked_timer: Option<NonZeroU8>) -> Self {
         Self {
             id,
             backup: 0,
@@ -45,7 +45,7 @@ impl AudioChannelTimer{
         }
     }
 
-    pub fn linked_timer(&self) -> Option<usize> {
+    pub fn linked_timer(&self) -> Option<NonZeroU8> {
         self.linked_timer
     }
 
diff --git a/src/mikey/timers/base_timer.rs b/src/mikey/timers/base_timer.rs
index 48c35cf..60a8828 100644
--- a/src/mikey/timers/base_timer.rs
+++ b/src/mikey/timers/base_timer.rs
@@ -12,7 +12,7 @@ pub struct BaseTimer {
     control_b: u8,
     clock_ticks: Option<u32>,
     next_trigger_tick: u64,
-    linked_timer: Option<usize>,
+    linked_timer: Option<NonZeroU8>,
     triggered: bool,
     is_linked: bool,
     count_enabled: bool,
@@ -20,7 +20,7 @@ pub struct BaseTimer {
 }
 
 impl BaseTimer{
-    pub fn new(id: u8, linked_timer: Option<usize>) -> Self {
+    pub fn new(id: u8, linked_timer: Option<NonZeroU8>) -> Self {
         Self {
             id,
             int: 1 << id,
@@ -38,7 +38,7 @@ impl BaseTimer{
         }
     }
 
-    pub fn linked_timer(&self) -> Option<usize> {
+    pub fn linked_timer(&self) -> Option<NonZeroU8> {
         self.linked_timer
     }
 
diff --git a/src/mikey/timers/mod.rs b/src/mikey/timers/mod.rs
index d0f5546..809363f 100644
--- a/src/mikey/timers/mod.rs
+++ b/src/mikey/timers/mod.rs
@@ -1,6 +1,7 @@
 pub mod audio_channel_timer;
 pub mod base_timer;
 
+use core::num::{NonZero, NonZeroU8};
 use audio_channel_timer::AudioChannelTimer;
 use base_timer::BaseTimer;
 use log::trace;
@@ -8,7 +9,7 @@ use crate::mikey::*;
 
 const TIMER_TICKS_COUNT: u16 = (0.000001 / CRYSTAL_TICK_LENGTH) as u16; // 1us/62.5ns
 
-const TIMER_LINKS: [Option<usize>; 12] = [Some(2), Some(3), Some(4), Some(5), None, Some(7), None, Some(8), Some(9), Some(10), Some(11), Some(1)];
+const TIMER_LINKS: [Option<NonZeroU8>; 12] = [Some(NonZero::new(2).unwrap()), Some(NonZero::new(3).unwrap()), Some(NonZero::new(4).unwrap()), Some(NonZero::new(5).unwrap()), None, Some(NonZero::new(7).unwrap()), None, Some(NonZero::new(8).unwrap()), Some(NonZero::new(9).unwrap()), Some(NonZero::new(10).unwrap()), Some(NonZero::new(11).unwrap()), Some(NonZero::new(1).unwrap())];
 const TIMER_COUNT: u8 = 12;
 
 const CTRLA_INTERRUPT_BIT: u8 = 0b10000000;
@@ -105,8 +106,8 @@ impl Timers {
     }
 
     #[inline(always)]
-    fn tick_linked_timer(&mut self, timer_id: usize) -> u8 {
-        match &mut self.timers[timer_id] {
+    fn tick_linked_timer(&mut self, timer_id: NonZeroU8) -> u8 {
+        match &mut self.timers[timer_id.get() as usize] {
             TimerType::Base(t) => tick_linked_timer!(self, t),
             TimerType::Audio(t) => tick_linked_timer!(self, t),
         }