From e0973e19fc378ad2a69f2db2b0596e2808b6058a Mon Sep 17 00:00:00 2001
From: lioncash <mathew1800@gmail.com>
Date: Sat, 6 Nov 2021 23:29:38 -0400
Subject: [PATCH] OpcodeDispatcher: Implement handling for BLSMSK

---
 .../Interface/Core/OpcodeDispatcher.cpp       | 28 ++++++++++++++++
 .../Source/Interface/Core/OpcodeDispatcher.h  |  1 +
 .../Interface/Core/X86Tables/VEXTables.cpp    |  2 +-
 unittests/ASM/VEX/blsmsk.asm                  | 32 +++++++++++++++++++
 4 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 unittests/ASM/VEX/blsmsk.asm

diff --git a/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp b/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
index 1fe41cb64..8cf099bda 100644
--- a/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
+++ b/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
@@ -2261,6 +2261,33 @@ void OpDispatchBuilder::BLSIBMIOp(OpcodeArgs) {
   }
 }
 
+void OpDispatchBuilder::BLSMSKBMIOp(OpcodeArgs) {
+  // Equivalent to: (Src - 1) ^ Src
+
+  auto Zero = _Constant(0);
+  auto One = _Constant(1);
+
+  auto* Src = LoadSource(GPRClass, Op, Op->Src[0], Op->Flags, -1);
+  auto Result = _Xor(_Sub(Src, One), Src);
+
+  StoreResult(GPRClass, Op, Result, -1);
+
+  // Now for the flags.
+  SetRFLAG<X86State::RFLAG_ZF_LOC>(Zero);
+  SetRFLAG<X86State::RFLAG_OF_LOC>(Zero);
+  SetRFLAG<X86State::RFLAG_AF_LOC>(Zero);
+  if (CTX->Config.ABINoPF) {
+    _InvalidateFlags(1UL << X86State::RFLAG_PF_LOC);
+  } else {
+    SetRFLAG<X86State::RFLAG_PF_LOC>(Zero);
+  }
+
+  auto CFOp = _Select(IR::COND_EQ,
+                      Src, Zero,
+                      Zero, One);
+  SetRFLAG<X86State::RFLAG_CF_LOC>(CFOp);
+}
+
 void OpDispatchBuilder::BLSRBMIOp(OpcodeArgs) {
   // Equivalent to: (Src - 1) & Src
 
@@ -5981,6 +6008,7 @@ constexpr uint16_t PF_F2 = 3;
   #define OPD(group, pp, opcode) (((group - X86Tables::InstType::TYPE_VEX_GROUP_12) << 4) | (pp << 3) | (opcode))
     const std::vector<std::tuple<uint8_t, uint8_t, X86Tables::OpDispatchPtr>> VEXGroupTable = {
       {OPD(X86Tables::InstType::TYPE_VEX_GROUP_17, 0, 0b001), 1, &OpDispatchBuilder::BLSRBMIOp},
+      {OPD(X86Tables::InstType::TYPE_VEX_GROUP_17, 0, 0b010), 1, &OpDispatchBuilder::BLSMSKBMIOp},
       {OPD(X86Tables::InstType::TYPE_VEX_GROUP_17, 0, 0b011), 1, &OpDispatchBuilder::BLSIBMIOp},
     };
   #undef OPD
diff --git a/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.h b/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.h
index 92f2d81bf..5e3e84c45 100644
--- a/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.h
+++ b/External/FEXCore/Source/Interface/Core/OpcodeDispatcher.h
@@ -328,6 +328,7 @@ public:
   void ANDNBMIOp(OpcodeArgs);
   void BEXTRBMIOp(OpcodeArgs);
   void BLSIBMIOp(OpcodeArgs);
+  void BLSMSKBMIOp(OpcodeArgs);
   void BLSRBMIOp(OpcodeArgs);
 
   // X87 Ops
diff --git a/External/FEXCore/Source/Interface/Core/X86Tables/VEXTables.cpp b/External/FEXCore/Source/Interface/Core/X86Tables/VEXTables.cpp
index da9383067..bb7096585 100644
--- a/External/FEXCore/Source/Interface/Core/X86Tables/VEXTables.cpp
+++ b/External/FEXCore/Source/Interface/Core/X86Tables/VEXTables.cpp
@@ -504,7 +504,7 @@ void InitializeVEXTables() {
     {OPD(TYPE_VEX_GROUP_15, 1, 0b011), 1, X86InstInfo{"VSTMXCSR", TYPE_UNDEC, FLAGS_MODRM, 0, nullptr}},
 
     {OPD(TYPE_VEX_GROUP_17, 0, 0b001), 1, X86InstInfo{"BLSR",     TYPE_INST, FLAGS_MODRM | FLAGS_VEX_DST, 0, nullptr}},
-    {OPD(TYPE_VEX_GROUP_17, 0, 0b010), 1, X86InstInfo{"BLSMSK",   TYPE_UNDEC, FLAGS_MODRM, 0, nullptr}},
+    {OPD(TYPE_VEX_GROUP_17, 0, 0b010), 1, X86InstInfo{"BLSMSK",   TYPE_INST, FLAGS_MODRM | FLAGS_VEX_DST, 0, nullptr}},
     {OPD(TYPE_VEX_GROUP_17, 0, 0b011), 1, X86InstInfo{"BLSI",     TYPE_INST, FLAGS_MODRM | FLAGS_VEX_DST, 0, nullptr}},
   };
 #undef OPD
diff --git a/unittests/ASM/VEX/blsmsk.asm b/unittests/ASM/VEX/blsmsk.asm
new file mode 100644
index 000000000..ee8d2fe9c
--- /dev/null
+++ b/unittests/ASM/VEX/blsmsk.asm
@@ -0,0 +1,32 @@
+%ifdef CONFIG
+{
+  "RegData": {
+      "RAX": "1",
+      "RBX": "0xFF00000000000000",
+      "RCX": "0x01FFFFFFFFFFFFFF",
+      "RDX": "1",
+      "RSI": "0xFF000000",
+      "RDI": "0x01FFFFFF"
+  }
+}
+%endif
+
+; Trivial test, this should result in 1.
+mov rax, 11
+blsmsk rax, rax
+
+; Results in 0x01FFFFFFFFFFFFFF being placed into RCX
+mov rbx, 0xFF00000000000000
+blsmsk rcx, rbx
+
+; Same tests but with 32-bit registers
+
+; Trivial test, this should result in 1.
+mov edx, 11
+blsmsk edx, edx
+
+; Results in 0x01FFFFFF being placed in EDI
+mov rsi, 0xFF000000
+blsmsk edi, esi
+
+hlt
\ No newline at end of file