From 65c988aaadb9e903d1a4719700ba1d77b4f97004 Mon Sep 17 00:00:00 2001
From: jsmolka <jsmolka@pm.me>
Date: Sat, 21 Nov 2020 16:47:37 +0100
Subject: [PATCH] GBA Memory: Return correct byte in out of bounds ROM read

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

diff --git a/CHANGES b/CHANGES
index bef7697a9..e774851a4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,7 @@ Emulation fixes:
  - ARM: Fix Addressing mode 1 shifter on rs == pc (fixes mgba.io/i/1926)
  - GBA I/O: Ignore high bits on IME
  - GBA Memory: Mark Famicom Mini games 22 through 28 as non-mirroring
+ - GBA Memory: Return correct byte for odd ROM open bus addresses
 Other fixes:
  - CMake: Fix build with downstream minizip that exports incompatible symbols
  - Core: Fix threading improperly setting paused state while interrupted
diff --git a/src/gba/memory.c b/src/gba/memory.c
index d2ba5a419..9d185c2fd 100644
--- a/src/gba/memory.c
+++ b/src/gba/memory.c
@@ -670,7 +670,7 @@ uint32_t GBALoad8(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
 			value = GBAVFameGetPatternValue(address, 8);
 		} else {
 			mLOG(GBA_MEM, GAME_ERROR, "Out of bounds ROM Load8: 0x%08X", address);
-			value = (address >> 1) & 0xFF;
+			value = ((address >> 1) >> ((address & 1) * 8)) & 0xFF;
 		}
 		break;
 	case REGION_CART_SRAM: