From 0a4cafcd57637b17c8efba9b607f81d5e4511584 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 27 Dec 2022 20:39:19 -0800
Subject: [PATCH] GB BIOS: Include timing in degenerate ArcTan2 cases (fixes
 #2763)

---
 CHANGES        | 1 +
 src/gba/bios.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/CHANGES b/CHANGES
index 00e8d7587..06b1a5235 100644
--- a/CHANGES
+++ b/CHANGES
@@ -7,6 +7,7 @@ Emulation fixes:
  - GB Audio: Fix channel 3 volume being changed between samples (fixes mgba.io/i/1896)
  - GB Audio: Fix up boot sequence
  - GB Audio: Fix updating channels other than 2 when writing NR5x
+ - GB BIOS: Include timing in degenerate ArcTan2 cases (fixes mgba.io/i/2763)
  - GB Memory: Actually, HDMAs should start when LCD is off (fixes mgba.io/i/2662)
  - GB Serialize: Don't write BGP/OBP when loading SCGB state (fixes mgba.io/i/2694)
  - GB SIO: Further fix bidirectional transfer starting
diff --git a/src/gba/bios.c b/src/gba/bios.c
index d824830aa..1d0c0dd10 100644
--- a/src/gba/bios.c
+++ b/src/gba/bios.c
@@ -336,12 +336,14 @@ static int16_t _ArcTan(int32_t i, int32_t* r1, int32_t* r3, uint32_t* cycles) {
 
 static int16_t _ArcTan2(int32_t x, int32_t y, int32_t* r1, uint32_t* cycles) {
 	if (!y) {
+		*cycles = 11;
 		if (x >= 0) {
 			return 0;
 		}
 		return 0x8000;
 	}
 	if (!x) {
+		*cycles = 11;
 		if (y >= 0) {
 			return 0x4000;
 		}