From c9a4021537bf9846b8c5e051399563a018e066ac Mon Sep 17 00:00:00 2001
From: JosJuice <josjuice@gmail.com>
Date: Sun, 25 Jul 2021 19:18:43 +0200
Subject: [PATCH] JitArm64: Implement mtfsb1x

Part 4 of implementing the FPSCR system register instructions.
---
 Source/Core/Core/PowerPC/JitArm64/Jit.h       |  1 +
 .../JitArm64/JitArm64_SystemRegisters.cpp     | 28 +++++++++++++++++++
 .../Core/PowerPC/JitArm64/JitArm64_Tables.cpp |  2 +-
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/Source/Core/Core/PowerPC/JitArm64/Jit.h b/Source/Core/Core/PowerPC/JitArm64/Jit.h
index f4ca4c0485..aead64de77 100644
--- a/Source/Core/Core/PowerPC/JitArm64/Jit.h
+++ b/Source/Core/Core/PowerPC/JitArm64/Jit.h
@@ -120,6 +120,7 @@ public:
   void mcrfs(UGeckoInstruction inst);
   void mffsx(UGeckoInstruction inst);
   void mtfsb0x(UGeckoInstruction inst);
+  void mtfsb1x(UGeckoInstruction inst);
 
   // LoadStore
   void lXX(UGeckoInstruction inst);
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_SystemRegisters.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_SystemRegisters.cpp
index 20e80ace96..4a40ee7450 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_SystemRegisters.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_SystemRegisters.cpp
@@ -788,3 +788,31 @@ void JitArm64::mtfsb0x(UGeckoInstruction inst)
   if (inst.CRBD >= 29)
     UpdateRoundingMode();
 }
+
+void JitArm64::mtfsb1x(UGeckoInstruction inst)
+{
+  INSTRUCTION_START
+  JITDISABLE(bJITSystemRegistersOff);
+  FALLBACK_IF(inst.Rc);
+
+  u32 mask = 0x80000000 >> inst.CRBD;
+
+  ARM64Reg WA = gpr.GetReg();
+
+  LDR(IndexType::Unsigned, WA, PPC_REG, PPCSTATE_OFF(fpscr));
+  if (mask & FPSCR_ANY_X)
+  {
+    ARM64Reg WB = gpr.GetReg();
+    TST(WA, LogicalImm(mask, 32));
+    ORR(WB, WA, LogicalImm(1 << 31, 32));
+    CSEL(WA, WA, WB, CCFlags::CC_NEQ);
+    gpr.Unlock(WB);
+  }
+  ORR(WA, WA, LogicalImm(mask, 32));
+  STR(IndexType::Unsigned, WA, PPC_REG, PPCSTATE_OFF(fpscr));
+
+  gpr.Unlock(WA);
+
+  if (inst.CRBD >= 29)
+    UpdateRoundingMode();
+}
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Tables.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Tables.cpp
index 00a563ad5c..4d44cce2dc 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Tables.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Tables.cpp
@@ -317,7 +317,7 @@ constexpr std::array<GekkoOPTemplate, 15> table63{{
     {64, &JitArm64::mcrfs},                   // mcrfs
     {583, &JitArm64::mffsx},                  // mffsx
     {70, &JitArm64::mtfsb0x},                 // mtfsb0x
-    {38, &JitArm64::FallBackToInterpreter},   // mtfsb1x
+    {38, &JitArm64::mtfsb1x},                 // mtfsb1x
     {134, &JitArm64::FallBackToInterpreter},  // mtfsfix
     {711, &JitArm64::FallBackToInterpreter},  // mtfsfx
 }};