From 54fba4c4611141b45c76471cad9981dadb03389c Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Fri, 20 Nov 2020 01:15:46 -0800
Subject: [PATCH] GBA I/O: Ignore high bits on IME

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

diff --git a/CHANGES b/CHANGES
index aba1aa345..39907c7f5 100644
--- a/CHANGES
+++ b/CHANGES
@@ -32,6 +32,7 @@ Emulation fixes:
  - GBA DMA: Linger last DMA on bus (fixes mgba.io/i/301 and mgba.io/i/1320)
  - GBA DMA: Fix ordering and timing of overlapping DMAs
  - GBA I/O: Green swap register should be readable
+ - GBA I/O: Ignore high bits on IME
  - GBA Memory: Improve gamepak prefetch timing
  - GBA Memory: Stall on VRAM access in mode 2 (fixes mgba.io/i/190)
  - GBA Memory: Improve robustness of Matrix memory support
diff --git a/src/gba/io.c b/src/gba/io.c
index 6a1037bf3..b544db166 100644
--- a/src/gba/io.c
+++ b/src/gba/io.c
@@ -557,7 +557,7 @@ void GBAIOWrite(struct GBA* gba, uint32_t address, uint16_t value) {
 			GBATestIRQ(gba, 1);
 			return;
 		case REG_IME:
-			gba->memory.io[REG_IME >> 1] = value;
+			gba->memory.io[REG_IME >> 1] = value & 1;
 			GBATestIRQ(gba, 1);
 			return;
 		case REG_MAX: