From 117067344708607d59bd1b334e7c6658dae28a34 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Thu, 26 May 2022 17:10:37 -0300
Subject: [PATCH] fix: resolve issue when handling event sooner than expected

---
 src/emu.zig       | 5 +----
 src/scheduler.zig | 8 +++++---
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/emu.zig b/src/emu.zig
index 002874c..492268b 100644
--- a/src/emu.zig
+++ b/src/emu.zig
@@ -51,10 +51,7 @@ pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi) void {
     const frame_end = sched.tick + cycles_per_frame;
 
     while (true) {
-        const next = sched.nextTimestamp();
-        const run_until = std.math.min(next, frame_end);
-
-        while (sched.tick < run_until) {
+        while (sched.tick < std.math.min(frame_end, sched.nextTimestamp())) {
             if (cpu.bus.io.haltcnt == .Execute) cpu.step() else sched.tick += 1;
             cpu.handleDMATransfers();
         }
diff --git a/src/scheduler.zig b/src/scheduler.zig
index 5f22521..43c4b9e 100644
--- a/src/scheduler.zig
+++ b/src/scheduler.zig
@@ -90,10 +90,12 @@ pub const Scheduler = struct {
         self.queue.add(.{ .kind = kind, .tick = self.now() + end }) catch unreachable;
     }
 
-    pub fn nextTimestamp(self: *Self) u64 {
-        if (self.queue.peek()) |e| return e.tick;
+    pub inline fn nextTimestamp(self: *const Self) u64 {
+        @setRuntimeSafety(false);
 
-        unreachable; // There's always the HeatDeath event scheduled
+        // Typically you'd use PriorityQueue.peek here, but there's always at least a HeatDeath
+        // event in the PQ so we can just do this instead. Should be faster in ReleaseSafe
+        return self.queue.items[0].tick;
     }
 };