From bedbaf39789c61494f5d91d98c4f50696ab7ce1d Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Mon, 26 Oct 2020 21:25:49 -0700
Subject: [PATCH] GBA Serialize: Ensure program counter is aligned when loading

---
 CHANGES             | 1 +
 src/gba/serialize.c | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/CHANGES b/CHANGES
index f6597ab52..becbef98d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -71,6 +71,7 @@ Other fixes:
  - GBA: Disable more checks when loading GS save with checks disabled (fixes mgba.io/i/1851)
  - GBA: Fix endianness issues in renderer proxy
  - GBA Core: Fix memory leak when loading symbols
+ - GBA Serialize: Ensure program counter is aligned when loading
  - Qt: Force OpenGL paint engine creation thread (fixes mgba.io/i/1642)
  - Qt: Fix static compilation in MinGW (fixes mgba.io/i/1769)
  - Qt: Fix a race condition in the frame inspector
diff --git a/src/gba/serialize.c b/src/gba/serialize.c
index 0e3c43f8c..464cef460 100644
--- a/src/gba/serialize.c
+++ b/src/gba/serialize.c
@@ -154,6 +154,11 @@ bool GBADeserialize(struct GBA* gba, const struct GBASerializedState* state) {
 		LOAD_32(gba->cpu->bankedSPSRs[i], i * sizeof(gba->cpu->bankedSPSRs[0]), state->cpu.bankedSPSRs);
 	}
 	gba->cpu->privilegeMode = gba->cpu->cpsr.priv;
+	uint32_t pcMask = (gba->cpu->executionMode == MODE_THUMB ? WORD_SIZE_THUMB : WORD_SIZE_ARM) - 1;
+	if (gba->cpu->gprs[ARM_PC] & pcMask) {
+		mLOG(GBA_STATE, WARN, "Savestate has unaligned PC and is probably corrupted");
+		gba->cpu->gprs[ARM_PC] &= ~pcMask;
+	}
 	gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
 	if (state->biosPrefetch) {
 		LOAD_32(gba->memory.biosPrefetch, 0, &state->biosPrefetch);