From 1aa7b62e92fb7b7c842d2d1b91ca3b08592ec8f9 Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Sat, 27 Jul 2019 19:56:18 +0100
Subject: [PATCH] A32/Thumb: Correct behaviour for UDF and Unpredictable
 instructions

Raise an exception instead of calling the interpreter and ASSERT-ing respectively.
---
 src/frontend/A32/translate/impl/thumb16.cpp       |  2 +-
 src/frontend/A32/translate/impl/translate_thumb.h |  1 +
 src/frontend/A32/translate/translate_thumb.cpp    | 11 +++++++++--
 tests/A32/testenv.h                               |  2 +-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/frontend/A32/translate/impl/thumb16.cpp b/src/frontend/A32/translate/impl/thumb16.cpp
index 9d70b1ea..bf19e265 100644
--- a/src/frontend/A32/translate/impl/thumb16.cpp
+++ b/src/frontend/A32/translate/impl/thumb16.cpp
@@ -885,7 +885,7 @@ bool ThumbTranslatorVisitor::thumb16_CBZ_CBNZ(bool nonzero, Imm<1> i, Imm<5> imm
 }
 
 bool ThumbTranslatorVisitor::thumb16_UDF() {
-    return InterpretThisInstruction();
+    return UndefinedInstruction();
 }
 
 // BX <Rm>
diff --git a/src/frontend/A32/translate/impl/translate_thumb.h b/src/frontend/A32/translate/impl/translate_thumb.h
index db053d3c..9aa21dab 100644
--- a/src/frontend/A32/translate/impl/translate_thumb.h
+++ b/src/frontend/A32/translate/impl/translate_thumb.h
@@ -29,6 +29,7 @@ struct ThumbTranslatorVisitor final {
 
     bool InterpretThisInstruction();
     bool UnpredictableInstruction();
+    bool UndefinedInstruction();
     bool RaiseException(Exception exception);
 
     // thumb16
diff --git a/src/frontend/A32/translate/translate_thumb.cpp b/src/frontend/A32/translate/translate_thumb.cpp
index 4e121277..21b0949c 100644
--- a/src/frontend/A32/translate/translate_thumb.cpp
+++ b/src/frontend/A32/translate/translate_thumb.cpp
@@ -122,12 +122,19 @@ bool ThumbTranslatorVisitor::InterpretThisInstruction() {
 }
 
 bool ThumbTranslatorVisitor::UnpredictableInstruction() {
-    ASSERT_MSG(false, "UNPREDICTABLE");
+    ir.ExceptionRaised(Exception::UnpredictableInstruction);
+    ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
+    return false;
+}
+
+bool ThumbTranslatorVisitor::UndefinedInstruction() {
+    ir.ExceptionRaised(Exception::UndefinedInstruction);
+    ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
     return false;
 }
 
 bool ThumbTranslatorVisitor::RaiseException(Exception exception) {
-    ir.BranchWritePC(ir.Imm32(ir.current_location.PC() + 2));
+    ir.BranchWritePC(ir.Imm32(ir.current_location.PC() + 2)); // TODO: T32
     ir.ExceptionRaised(exception);
     ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
     return false;
diff --git a/tests/A32/testenv.h b/tests/A32/testenv.h
index a1968ff3..f4db4de4 100644
--- a/tests/A32/testenv.h
+++ b/tests/A32/testenv.h
@@ -78,7 +78,7 @@ public:
         MemoryWrite32(vaddr + 4, static_cast<u32>(value >> 32));
     }
 
-    void InterpreterFallback(u32 pc, size_t num_instructions) override { ASSERT_MSG(false, "InterpreterFallback({:08x}, {})", pc, num_instructions); }
+    void InterpreterFallback(u32 pc, size_t num_instructions) override { ASSERT_MSG(false, "InterpreterFallback({:08x}, {}) code = {:08x}", pc, num_instructions, MemoryReadCode(pc)); }
 
     void CallSVC(std::uint32_t swi) override { ASSERT_MSG(false, "CallSVC({})", swi); }