From 6cf47e0ce0efc76a683fa546c40d34cff5222fb0 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Sun, 7 Feb 2021 17:16:05 -0500
Subject: [PATCH] thumb32: Implement SMULL

---
 src/CMakeLists.txt                            |  1 +
 src/frontend/A32/decoder/thumb32.inc          |  2 +-
 .../translate/impl/thumb32_long_multiply.cpp  | 30 +++++++++++++++++++
 .../A32/translate/impl/translate_thumb.h      |  3 ++
 4 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 src/frontend/A32/translate/impl/thumb32_long_multiply.cpp

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5e3ea5c2..300393f9 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -152,6 +152,7 @@ if ("A32" IN_LIST DYNARMIC_FRONTENDS)
         frontend/A32/translate/impl/synchronization.cpp
         frontend/A32/translate/impl/thumb16.cpp
         frontend/A32/translate/impl/thumb32.cpp
+        frontend/A32/translate/impl/thumb32_long_multiply.cpp
         frontend/A32/translate/impl/thumb32_misc.cpp
         frontend/A32/translate/impl/thumb32_multiply.cpp
         frontend/A32/translate/impl/thumb32_parallel.cpp
diff --git a/src/frontend/A32/decoder/thumb32.inc b/src/frontend/A32/decoder/thumb32.inc
index d7b8b953..cd61274d 100644
--- a/src/frontend/A32/decoder/thumb32.inc
+++ b/src/frontend/A32/decoder/thumb32.inc
@@ -279,7 +279,7 @@ INST(thumb32_USAD8,          "USAD8",                    "111110110111nnnn1111dd
 INST(thumb32_USADA8,         "USADA8",                   "111110110111nnnnaaaadddd0000mmmm")
 
 // Long Multiply, Long Multiply Accumulate, and Divide
-//INST(thumb32_SMULL,          "SMULL",                    "111110111000------------0000----")
+INST(thumb32_SMULL,          "SMULL",                    "111110111000nnnnllllhhhh0000mmmm")
 //INST(thumb32_SDIV,           "SDIV",                     "111110111001------------1111----")
 //INST(thumb32_UMULL,          "UMULL",                    "111110111010------------0000----")
 //INST(thumb32_UDIV,           "UDIV",                     "111110111011------------1111----")
diff --git a/src/frontend/A32/translate/impl/thumb32_long_multiply.cpp b/src/frontend/A32/translate/impl/thumb32_long_multiply.cpp
new file mode 100644
index 00000000..921d8638
--- /dev/null
+++ b/src/frontend/A32/translate/impl/thumb32_long_multiply.cpp
@@ -0,0 +1,30 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2021 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#include "frontend/A32/translate/impl/translate_thumb.h"
+
+namespace Dynarmic::A32 {
+
+bool ThumbTranslatorVisitor::thumb32_SMULL(Reg n, Reg dLo, Reg dHi, Reg m) {
+    if (dLo == Reg::PC || dHi == Reg::PC || n == Reg::PC || m == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+
+    if (dHi == dLo) {
+        return UnpredictableInstruction();
+    }
+
+    const auto n64 = ir.SignExtendWordToLong(ir.GetRegister(n));
+    const auto m64 = ir.SignExtendWordToLong(ir.GetRegister(m));
+    const auto result = ir.Mul(n64, m64);
+    const auto lo = ir.LeastSignificantWord(result);
+    const auto hi = ir.MostSignificantWord(result).result;
+
+    ir.SetRegister(dLo, lo);
+    ir.SetRegister(dHi, hi);
+    return true;
+}
+
+} // namespace Dynarmic::A32
diff --git a/src/frontend/A32/translate/impl/translate_thumb.h b/src/frontend/A32/translate/impl/translate_thumb.h
index 24b449cc..7599bca9 100644
--- a/src/frontend/A32/translate/impl/translate_thumb.h
+++ b/src/frontend/A32/translate/impl/translate_thumb.h
@@ -116,6 +116,9 @@ struct ThumbTranslatorVisitor final {
     bool thumb32_BLX_imm(Imm<11> hi, Imm<11> lo);
     bool thumb32_UDF();
 
+    // thumb32 long multiply, long multiply accumulate, and divide instructions
+    bool thumb32_SMULL(Reg n, Reg dLo, Reg dHi, Reg m);
+
     // thumb32 miscellaneous instructions
     bool thumb32_CLZ(Reg n, Reg d, Reg m);
     bool thumb32_QADD(Reg n, Reg d, Reg m);