From d7ecdb5e4eda3e195d6d319f94280486d01d0bc3 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Sat, 30 May 2020 17:00:07 -0700
Subject: [PATCH] GBA: Fix timing advancing too quickly in rare cases

---
 CHANGES       | 1 +
 src/gba/gba.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index 55bb9ba99..cedefd7bc 100644
--- a/CHANGES
+++ b/CHANGES
@@ -11,6 +11,7 @@ Emulation fixes:
  - GB Video: Fix state after skipping BIOS (fixes mgba.io/i/1715 and mgba.io/i/1716)
  - GB Video: Fix BGPS value after skipping BIOS (fixes mgba.io/i/1717)
  - GBA: Add missing RTC overrides for Legendz games
+ - GBA: Fix timing advancing too quickly in rare cases
  - GBA BIOS: Implement dummy sound driver calls
  - GBA BIOS: Improve HLE BIOS timing
  - GBA BIOS: Reset renderer when RegisterRamReset called (fixes mgba.io/i/1756)
diff --git a/src/gba/gba.c b/src/gba/gba.c
index 1ae1ae832..7a4bcea0d 100644
--- a/src/gba/gba.c
+++ b/src/gba/gba.c
@@ -282,7 +282,7 @@ static void GBAProcessEvents(struct ARMCore* cpu) {
 				mLOG(GBA, FATAL, "Negative cycles passed: %i", cycles);
 			}
 #endif
-			nextEvent = mTimingTick(&gba->timing, nextEvent + cycles);
+			nextEvent = mTimingTick(&gba->timing, cycles < nextEvent ? nextEvent : cycles);
 		} while (gba->cpuBlocked);
 
 		cpu->nextEvent = nextEvent;