From f9bb0460d8d21356a181be96b60527f8cff1ca22 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Wed, 25 May 2022 12:15:11 -0300
Subject: [PATCH] perf: don't check scheduler every iteration of runFrame loop

~20fps gain in Pokemon Emerald, nice
---
 src/emu.zig | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/emu.zig b/src/emu.zig
index 193c0eb..acaf07d 100644
--- a/src/emu.zig
+++ b/src/emu.zig
@@ -51,13 +51,15 @@ pub fn runFrame(sched: *Scheduler, cpu: *Arm7tdmi) void {
     const frame_end = sched.tick + cycles_per_frame;
 
     while (sched.tick < frame_end) {
-        if (cpu.bus.io.haltcnt == .Halt) sched.tick += 1;
-        if (cpu.bus.io.haltcnt == .Execute) cpu.step();
-        cpu.handleDMATransfers();
+        const next = sched.nextTimestamp();
+        if (next > frame_end) break;
 
-        while (sched.tick >= sched.nextTimestamp()) {
-            sched.handleEvent(cpu);
+        while (sched.tick < next) {
+            if (cpu.bus.io.haltcnt == .Execute) cpu.step() else sched.tick += 1;
+            cpu.handleDMATransfers();
         }
+
+        sched.handleEvent(cpu);
     }
 }