From ec14557a1e90314c47b0642079e0408ec3153aa8 Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Sat, 9 May 2015 00:23:56 -0700
Subject: [PATCH] ARM7: Make illegal instruction decoding consistent between
 ARM and Thumb

---
 CHANGES                 | 1 +
 src/arm/decoder-arm.c   | 8 ++++++--
 src/arm/decoder-thumb.c | 9 +++++++--
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/CHANGES b/CHANGES
index ca1a672a9..d6f70c4d9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -48,6 +48,7 @@ Bugfixes:
  - ARM7: Handle writeback for PC in addressing modes 2 and 3
  - GBA: Handle out-of-bounds I/O access
  - GBA: Fix bounds-checking on EEPROM access
+ - ARM7: Make illegal instruction decoding consistent between ARM and Thumb
 Misc:
  - Qt: Show multiplayer numbers in window title
  - Qt: Handle saving input settings better
diff --git a/src/arm/decoder-arm.c b/src/arm/decoder-arm.c
index 27f692de2..9dcc4bc77 100644
--- a/src/arm/decoder-arm.c
+++ b/src/arm/decoder-arm.c
@@ -380,8 +380,12 @@ DEFINE_DECODER_ARM(MRC, ILL, info->operandFormat = ARM_OPERAND_NONE;)
 
 // Begin miscellaneous definitions
 
-DEFINE_DECODER_ARM(BKPT, BKPT, info->operandFormat = ARM_OPERAND_NONE;) // Not strictly in ARMv4T, but here for convenience
-DEFINE_DECODER_ARM(ILL, ILL, info->operandFormat = ARM_OPERAND_NONE;) // Illegal opcode
+DEFINE_DECODER_ARM(BKPT, BKPT,
+	info->operandFormat = ARM_OPERAND_NONE;
+	info->traps = 1;) // Not strictly in ARMv4T, but here for convenience
+DEFINE_DECODER_ARM(ILL, ILL,
+	info->operandFormat = ARM_OPERAND_NONE;
+	info->traps = 1;) // Illegal opcode
 
 DEFINE_DECODER_ARM(MSR, MSR,
 	info->affectsCPSR = 1;
diff --git a/src/arm/decoder-thumb.c b/src/arm/decoder-thumb.c
index fb6aed9f5..6bf389508 100644
--- a/src/arm/decoder-thumb.c
+++ b/src/arm/decoder-thumb.c
@@ -281,8 +281,13 @@ DEFINE_LOAD_STORE_MULTIPLE_EX_THUMB(POPR, ARM_SP, LDM, ARM_MEMORY_INCREMENT_AFTE
 DEFINE_LOAD_STORE_MULTIPLE_EX_THUMB(PUSH, ARM_SP, STM, ARM_MEMORY_DECREMENT_BEFORE, 0)
 DEFINE_LOAD_STORE_MULTIPLE_EX_THUMB(PUSHR, ARM_SP, STM, ARM_MEMORY_DECREMENT_BEFORE, 1 << ARM_LR)
 
-DEFINE_THUMB_DECODER(ILL, ILL, info->traps = 1;)
-DEFINE_THUMB_DECODER(BKPT, BKPT, info->traps = 1;)
+DEFINE_THUMB_DECODER(ILL, ILL,
+	info->operandFormat = ARM_OPERAND_NONE;
+	info->traps = 1;)
+
+DEFINE_THUMB_DECODER(BKPT, BKPT,
+	info->operandFormat = ARM_OPERAND_NONE;
+	info->traps = 1;)
 
 DEFINE_THUMB_DECODER(B, B,
 	int16_t immediate = (opcode & 0x07FF) << 5;