CPU: Implement breakpoints in the recompiler

Both cop0 execution and debug breakpoints.

src/core/cpu_code_cache.cpp

@@ -57,6 +57,7 @@ static void DeallocateLUTs();
 static void ResetCodeLUT();
 static void SetCodeLUT(u32 pc, const void* function);
 static void InvalidateBlock(Block* block, BlockState new_state);
+static void ResetBlockCompileCount(Block* block);
 static void ClearBlocks();
 
 static Block* LookupBlock(u32 pc);
@@ -637,6 +638,12 @@ void CPU::CodeCache::InvalidateBlock(Block* block, BlockState new_state)
   block->state = new_state;
 }
 
+void CPU::CodeCache::ResetBlockCompileCount(Block* block)
+{
+  block->compile_frame = System::GetFrameNumber();
+  block->compile_count = 1;
+}
+
 void CPU::CodeCache::InvalidateAllRAMBlocks()
 {
   // TODO: maybe combine the backlink into one big instruction flush cache?
@@ -661,6 +668,35 @@ void CPU::CodeCache::InvalidateAllRAMBlocks()
   Bus::ClearRAMCodePageFlags();
 }
 
+void CPU::CodeCache::InvalidateOverlappingBlocks(u32 pc, bool force_recompile)
+{
+  const u32 table = pc >> LUT_TABLE_SHIFT;
+  Block** const blocks = s_block_lut[table];
+  if (!blocks)
+    return;
+
+  // optionally force recompilation
+  const BlockState new_block_state = force_recompile ? BlockState::NeedsRecompile : BlockState::Invalidated;
+
+  // loop through all blocks in the page
+  for (u32 i = 0; i < LUT_TABLE_SIZE; i++)
+  {
+    Block* const block = blocks[i];
+    if (!block)
+      continue;
+
+    if (pc >= block->pc && pc < (block->pc + block->size))
+    {
+      // this is pretty gross, if it's a RAM block we need to unlink it from the page list
+      RemoveBlockFromPageList(block);
+
+      // don't get trolled into the interpreter if bps are toggled
+      InvalidateBlock(block, new_block_state);
+      ResetBlockCompileCount(block);
+    }
+  }
+}
+
 void CPU::CodeCache::ClearBlocks()
 {
   for (u32 i = 0; i < Bus::RAM_8MB_CODE_PAGE_COUNT; i++)
@@ -859,6 +895,9 @@ bool CPU::CodeCache::ReadBlockInstructions(u32 start_pc, BlockInstructionList* i
   const bool use_icache = CPU::IsCachedAddress(start_pc);
   const bool dynamic_fetch_ticks = (!use_icache && Bus::GetMemoryAccessTimePtr(start_pc & PHYSICAL_MEMORY_ADDRESS_MASK,
                                                                                MemoryAccessSize::Word) != nullptr);
+  const bool debug_breakpoints_enabled = CPU::HasAnyBreakpoints(BreakpointType::Execute);
+  const bool cop0_breakpoints_enabled = CPU::g_state.cop0_regs.dcic.ExecutionBreakpointsEnabled();
+
   u32 pc = start_pc;
   bool is_branch_delay_slot = false;
   bool is_load_delay_slot = false;
@@ -926,6 +965,8 @@ bool CPU::CodeCache::ReadBlockInstructions(u32 start_pc, BlockInstructionList* i
     info.is_load_instruction = IsMemoryLoadInstruction(instruction);
     info.is_store_instruction = IsMemoryStoreInstruction(instruction);
     info.has_load_delay = InstructionHasLoadDelay(instruction);
+    info.is_cop0_breakpoint = (cop0_breakpoints_enabled && CPU::Cop0BreakpointMatchesPC(pc));
+    info.is_debug_breakpoint = (debug_breakpoints_enabled && CPU::HasBreakpointAtAddress(BreakpointType::Execute, pc));
 
     if (use_icache)
     {
@@ -972,6 +1013,19 @@ bool CPU::CodeCache::ReadBlockInstructions(u32 start_pc, BlockInstructionList* i
     // instruction is decoded now
     instructions->emplace_back(instruction, info);
 
+    if (info.is_cop0_breakpoint)
+    {
+      // end block early at breakpoints, the instruction doesn't actually get executed
+      WARNING_LOG("Ending block 0x{:08X} at 0x{:08X} due to cop0 breakpoint", start_pc, pc);
+      break;
+    }
+    else if (info.is_debug_breakpoint && is_branch_delay_slot)
+    {
+      // can't handle debug breakpoints in branch delay slots currently, since it can't resume
+      ERROR_LOG("Can't handle debug breakpoint at 0x{:08X} in branch delay slot, skipping block", pc);
+      return false;
+    }
+
     // if we're in a branch delay slot, the block is now done
     // except if this is a branch in a branch delay slot, then we grab the one after that, and so on...
     if (is_branch_delay_slot && !info.is_branch_instruction)
@@ -1539,6 +1593,13 @@ const void* CPU::CodeCache::GetInterpretUncachedBlockFunction()
   }
 }
 
+void CPU::CodeCache::ResetAndExitExecution()
+{
+  DEV_LOG("Resetting code cache and exiting execution");
+  Reset();
+  CPU::ExitExecution();
+}
+
 void CPU::CodeCache::CompileASMFunctions()
 {
   MemMap::BeginCodeWrite();
@@ -1710,13 +1771,11 @@ PageFaultHandler::HandlerResult CPU::CodeCache::HandleFastmemException(void* exc
   if (block)
   {
     // This is a bit annoying, we have to remove it from the page list if it's a RAM block.
+    // Need to reset the recompile count, otherwise it'll get trolled into an interpreter fallback.
     DEV_LOG("Queuing block {:08X} for recompilation due to backpatch", block->pc);
     RemoveBlockFromPageList(block);
     InvalidateBlock(block, BlockState::NeedsRecompile);
-
+    ResetBlockCompileCount(block);
-    // Need to reset the recompile count, otherwise it'll get trolled into an interpreter fallback.
-    block->compile_frame = System::GetFrameNumber();
-    block->compile_count = 1;
   }
 
   MemMap::EndCodeWrite();

src/core/cpu_code_cache.h

@@ -37,4 +37,7 @@ void InvalidateBlocksWithPageIndex(u32 page_index);
 /// Invalidates all blocks in the cache.
 void InvalidateAllRAMBlocks();
 
+/// Invalidates blocks with the specified PC, forcing recompilation.
+void InvalidateOverlappingBlocks(u32 pc, bool force_recompile);
+
 } // namespace CPU::CodeCache

src/core/cpu_code_cache_private.h

@@ -44,6 +44,8 @@ struct InstructionInfo
   bool is_load_instruction : 1;
   bool is_store_instruction : 1;
   bool is_load_delay_slot : 1;
+  bool is_cop0_breakpoint : 1;
+  bool is_debug_breakpoint : 1;
   bool is_last_instruction : 1;
   bool has_load_delay : 1;
 
@@ -233,6 +235,7 @@ void CommitFarCode(u32 length);
 void AlignCode(u32 alignment);
 
 const void* GetInterpretUncachedBlockFunction();
+void ResetAndExitExecution();
 
 void CompileOrRevalidateBlock(u32 start_pc);
 void DiscardAndRecompileBlock(u32 start_pc);

src/core/cpu_core.cpp

@@ -530,15 +530,18 @@ ALWAYS_INLINE_RELEASE void CPU::Cop0ExecutionBreakpointCheck()
   if (!g_state.cop0_regs.dcic.ExecutionBreakpointsEnabled())
     return;
 
-  const u32 pc = g_state.current_instruction_pc;
+  if (Cop0BreakpointMatchesPC(g_state.current_instruction_pc))
-  const u32 bpc = g_state.cop0_regs.BPC;
+    DispatchCop0ExecutionBreakpoint();
-  const u32 bpcm = g_state.cop0_regs.BPCM;
+}
 
-  // Break condition is "((PC XOR BPC) AND BPCM)=0".
+bool CPU::AreCop0ExecutionBreakpointsActive()
-  if (bpcm == 0 || ((pc ^ bpc) & bpcm) != 0u)
+{
-    return;
+  return (g_state.cop0_regs.dcic.ExecutionBreakpointsEnabled() && IsCop0ExecutionBreakpointUnmasked());
+}
 
-  DEV_LOG("Cop0 execution breakpoint at {:08X}", pc);
+void CPU::DispatchCop0ExecutionBreakpoint()
+{
+  DEV_LOG("Cop0 execution breakpoint at {:08X}", g_state.current_instruction_pc);
   g_state.cop0_regs.dcic.status_any_break = true;
   g_state.cop0_regs.dcic.status_bpc_code_break = true;
   DispatchCop0Breakpoint();
@@ -2013,15 +2016,19 @@ CPUExecutionMode CPU::GetCurrentExecutionMode()
 
 bool CPU::UpdateDebugDispatcherFlag()
 {
-  const bool has_any_breakpoints = (HasAnyBreakpoints() || s_break_type == ExecutionBreakType::SingleStep);
-
   const auto& dcic = g_state.cop0_regs.dcic;
   const bool has_cop0_breakpoints = dcic.super_master_enable_1 && dcic.super_master_enable_2 &&
                                     dcic.execution_breakpoint_enable && IsCop0ExecutionBreakpointUnmasked();
+  const bool has_execution_breakpoints = HasAnyBreakpoints(BreakpointType::Execute);
+  const bool requires_interpreter =
+    (HasAnyBreakpoints(BreakpointType::Read) || HasAnyBreakpoints(BreakpointType::Write) ||
+     s_break_type == ExecutionBreakType::SingleStep);
 
+  // TODO: Don't force the int just for cop0 breakpoints, they're cheap. Also need it for cop0 data breakpoints.
   const bool use_debug_dispatcher =
-    has_any_breakpoints || has_cop0_breakpoints || s_trace_to_log ||
+    s_trace_to_log || requires_interpreter ||
-    (g_settings.cpu_execution_mode == CPUExecutionMode::Interpreter && g_settings.bios_tty_logging);
+    (g_settings.cpu_execution_mode == CPUExecutionMode::Interpreter &&
+     (has_cop0_breakpoints || has_execution_breakpoints || g_settings.bios_tty_logging));
   if (use_debug_dispatcher == g_state.using_debug_dispatcher)
     return false;
 
@@ -2103,10 +2110,9 @@ void CPU::CheckForExecutionModeChange()
   fastjmp_jmp(&s_jmp_buf, 1);
 }
 
-bool CPU::HasAnyBreakpoints()
+bool CPU::HasAnyBreakpoints(BreakpointType type)
 {
-  return (GetBreakpointList(BreakpointType::Execute).size() + GetBreakpointList(BreakpointType::Read).size() +
+  return (GetBreakpointList(type).size() > 0);
-          GetBreakpointList(BreakpointType::Write).size()) > 0;
 }
 
 ALWAYS_INLINE CPU::BreakpointList& CPU::GetBreakpointList(BreakpointType type)
@@ -2129,11 +2135,8 @@ bool CPU::HasBreakpointAtAddress(BreakpointType type, VirtualMemoryAddress addre
   for (Breakpoint& bp : GetBreakpointList(type))
   {
     if (bp.enabled && (bp.address & 0x0FFFFFFFu) == (address & 0x0FFFFFFFu))
-    {
-      bp.hit_count++;
       return true;
   }
-  }
 
   return false;
 }
@@ -2174,12 +2177,16 @@ bool CPU::AddBreakpoint(BreakpointType type, VirtualMemoryAddress address, bool
 
   Breakpoint bp{address, nullptr, auto_clear ? 0 : s_breakpoint_counter++, 0, type, auto_clear, enabled};
   GetBreakpointList(type).push_back(std::move(bp));
-  if (UpdateDebugDispatcherFlag())
-    System::InterruptExecution();
 
   if (!auto_clear)
     Host::ReportDebuggerMessage(fmt::format("Added breakpoint at 0x{:08X}.", address));
 
+  if (type == BreakpointType::Execute && s_current_execution_mode != CPUExecutionMode::Interpreter && enabled)
+    CodeCache::InvalidateOverlappingBlocks(address, true);
+
+  if (UpdateDebugDispatcherFlag())
+    System::InterruptExecution();
+
   return true;
 }
 
@@ -2192,8 +2199,13 @@ bool CPU::AddBreakpointWithCallback(BreakpointType type, VirtualMemoryAddress ad
 
   Breakpoint bp{address, callback, 0, 0, type, false, true};
   GetBreakpointList(type).push_back(std::move(bp));
+
+  if (type == BreakpointType::Execute && s_current_execution_mode != CPUExecutionMode::Interpreter)
+    CodeCache::InvalidateOverlappingBlocks(address, true);
+
   if (UpdateDebugDispatcherFlag())
     System::InterruptExecution();
+
   return true;
 }
 
@@ -2209,12 +2221,15 @@ bool CPU::SetBreakpointEnabled(BreakpointType type, VirtualMemoryAddress address
                                           GetBreakpointTypeName(type), address));
   it->enabled = enabled;
 
-  if (UpdateDebugDispatcherFlag())
-    System::InterruptExecution();
-
   if (address == s_last_breakpoint_check_pc && !enabled)
     s_last_breakpoint_check_pc = INVALID_BREAKPOINT_PC;
 
+  if (type == BreakpointType::Execute && s_current_execution_mode != CPUExecutionMode::Interpreter)
+    CodeCache::InvalidateOverlappingBlocks(address, true);
+
+  if (UpdateDebugDispatcherFlag())
+    System::InterruptExecution();
+
   return true;
 }
 
@@ -2229,21 +2244,36 @@ bool CPU::RemoveBreakpoint(BreakpointType type, VirtualMemoryAddress address)
   Host::ReportDebuggerMessage(fmt::format("Removed {} breakpoint at 0x{:08X}.", GetBreakpointTypeName(type), address));
 
   bplist.erase(it);
-  if (UpdateDebugDispatcherFlag())
-    System::InterruptExecution();
 
   if (address == s_last_breakpoint_check_pc)
     s_last_breakpoint_check_pc = INVALID_BREAKPOINT_PC;
 
+  if (type == BreakpointType::Execute && s_current_execution_mode != CPUExecutionMode::Interpreter)
+    CodeCache::InvalidateOverlappingBlocks(address, true);
+
+  if (UpdateDebugDispatcherFlag())
+    System::InterruptExecution();
+
   return true;
 }
 
 void CPU::ClearBreakpoints()
 {
+  if (s_current_execution_mode != CPUExecutionMode::Interpreter)
+  {
+    for (const Breakpoint& bp : s_breakpoints[static_cast<u32>(BreakpointType::Execute)])
+    {
+      if (bp.enabled)
+        CodeCache::InvalidateOverlappingBlocks(bp.address, true);
+    }
+  }
+
   for (BreakpointList& bplist : s_breakpoints)
     bplist.clear();
+
   s_breakpoint_counter = 0;
   s_last_breakpoint_check_pc = INVALID_BREAKPOINT_PC;
+
   if (UpdateDebugDispatcherFlag())
     System::InterruptExecution();
 }
@@ -2390,6 +2420,21 @@ ALWAYS_INLINE_RELEASE void CPU::ExecutionBreakpointCheck()
   }
 }
 
+u32 CPU::DispatchDebugBreakpoint()
+{
+  const u32 prev_npc = g_state.npc;
+  DEV_LOG("Debug execution breakpoint at {:08X}", g_state.current_instruction_pc);
+
+  if (CheckBreakpointList(BreakpointType::Execute, g_state.current_instruction_pc))
+  {
+    s_break_type = ExecutionBreakType::None;
+    ExitExecution();
+  }
+
+  // return true if pc has changed and the rec needs to bail out
+  return BoolToUInt32(g_state.npc != prev_npc);
+}
+
 template<MemoryAccessType type>
 ALWAYS_INLINE_RELEASE void CPU::MemoryBreakpointCheck(VirtualMemoryAddress address)
 {
@@ -2587,6 +2632,8 @@ void CPU::CodeCache::InterpretUncachedBlock()
   if (!FetchInstructionForInterpreterFallback())
     return;
 
+  // TODO: needs to check debug breakpoints, for when the breakpoint is in a branch delay slot
+
   // At this point, pc contains the last address executed (in the previous block). The instruction has not been fetched
   // yet. pc shouldn't be updated until the fetch occurs, that way the exception occurs in the delay slot.
   bool in_branch_delay_slot = false;

src/core/cpu_core.h

@@ -229,7 +229,7 @@ using BreakpointList = std::vector<Breakpoint>;
 
 // Breakpoints
 const char* GetBreakpointTypeName(BreakpointType type);
-bool HasAnyBreakpoints();
+bool HasAnyBreakpoints(BreakpointType type);
 bool HasBreakpointAtAddress(BreakpointType type, VirtualMemoryAddress address);
 BreakpointList CopyBreakpointList(bool include_auto_clear = false, bool include_callbacks = false);
 bool AddBreakpoint(BreakpointType type, VirtualMemoryAddress address, bool auto_clear = false, bool enabled = true);

src/core/cpu_core_private.h

@@ -132,6 +132,22 @@ ALWAYS_INLINE static void StallUntilGTEComplete()
     (g_state.gte_completion_tick > g_state.pending_ticks) ? g_state.gte_completion_tick : g_state.pending_ticks;
 }
 
+// cop0 breakpoint check
+ALWAYS_INLINE static bool Cop0BreakpointMatchesPC(u32 pc)
+{
+  const u32 bpc = g_state.cop0_regs.BPC;
+  const u32 bpcm = g_state.cop0_regs.BPCM;
+
+  // Break condition is "((PC XOR BPC) AND BPCM)=0".
+  // TODO: is the != 0 here correct?
+  return (bpcm != 0 && ((pc ^ bpc) & bpcm) == 0u);
+}
+
+// cop0 breakpoint dispatch
+bool AreCop0ExecutionBreakpointsActive();
+void DispatchCop0ExecutionBreakpoint();
+u32 DispatchDebugBreakpoint();
+
 // kernel call interception
 void HandleA0Syscall();
 void HandleB0Syscall();

src/core/cpu_recompiler.cpp

@@ -350,6 +350,7 @@ bool CPU::Recompiler::Recompiler::TrySwapDelaySlot(Reg rs, Reg rt, Reg rd)
     return false;
 
   const Instruction* next_instruction = inst + 1;
+  const CodeCache::InstructionInfo* next_iinfo = iinfo + 1;
   DebugAssert(next_instruction < (m_block->Instructions() + m_block->size));
 
   const Reg opcode_rs = next_instruction->r.rs;
@@ -366,6 +367,10 @@ bool CPU::Recompiler::Recompiler::TrySwapDelaySlot(Reg rs, Reg rt, Reg rd)
   const u32 backup_instruction_pc = m_current_instruction_pc;
   const bool backup_instruction_delay_slot = m_current_instruction_branch_delay_slot;
 
+  // branch delay slots with a breakpoint can't be swapped
+  if (next_iinfo->is_cop0_breakpoint || next_iinfo->is_debug_breakpoint)
+    goto is_unsafe;
+
   if (next_instruction->bits == 0)
   {
     // nop
@@ -1188,6 +1193,13 @@ void CPU::Recompiler::Recompiler::CompileInstruction()
             m_current_instruction_pc, str);
 #endif
 
+  if (iinfo->is_cop0_breakpoint || iinfo->is_debug_breakpoint)
+  {
+    CompileExecutionBreakpointCheck();
+    if (m_block_ended)
+      return;
+  }
+
   m_cycles++;
 
   if (IsNopInstruction(*inst))

src/core/cpu_recompiler.h

@@ -119,6 +119,8 @@ protected:
       (FLUSH_CYCLES | FLUSH_GTE_DONE_CYCLE), // GTE cycles needed because it stalls when a GTE instruction is next.
     FLUSH_FOR_EARLY_BLOCK_EXIT =
       (FLUSH_FLUSH_MIPS_REGISTERS | FLUSH_CYCLES | FLUSH_GTE_DONE_CYCLE | FLUSH_PC | FLUSH_LOAD_DELAY),
+    FLUSH_FOR_BREAKPOINT =
+      (FLUSH_FLUSH_MIPS_REGISTERS | FLUSH_CYCLES | FLUSH_GTE_DONE_CYCLE | FLUSH_INSTRUCTION_BITS | FLUSH_FOR_C_CALL),
     FLUSH_FOR_INTERPRETER = (FLUSH_FLUSH_MIPS_REGISTERS | FLUSH_INVALIDATE_MIPS_REGISTERS |
                              FLUSH_FREE_CALLER_SAVED_REGISTERS | FLUSH_PC | FLUSH_CYCLES | FLUSH_INSTRUCTION_BITS |
                              FLUSH_LOAD_DELAY | FLUSH_GTE_DONE_CYCLE | FLUSH_INVALIDATE_SPECULATIVE_CONSTANTS),
@@ -338,6 +340,9 @@ protected:
 
   virtual void Compile_Fallback() = 0;
 
+  // returns true if further compilation should be skipped
+  virtual bool CompileExecutionBreakpointCheck() = 0;
+
   void Compile_j();
   virtual void Compile_jr(CompileFlags cf) = 0;
   void Compile_jr_const(CompileFlags cf);

src/core/cpu_recompiler_x64.cpp

@@ -579,6 +579,12 @@ void CPU::X64Recompiler::GenerateCall(const void* func, s32 arg1reg /*= -1*/, s3
 
 void CPU::X64Recompiler::EndBlock(const std::optional<u32>& newpc, bool do_event_test)
 {
+  if (iinfo->is_cop0_breakpoint && m_block_ended)
+  {
+    // block already ended by breakpoint
+    return;
+  }
+
   if (newpc.has_value())
   {
     if (m_dirty_pc || m_compiler_pc != newpc)
@@ -980,6 +986,39 @@ void CPU::X64Recompiler::Compile_Fallback()
   m_load_delay_dirty = EMULATE_LOAD_DELAYS;
 }
 
+bool CPU::X64Recompiler::CompileExecutionBreakpointCheck()
+{
+  // flush regs and instruction bits, since cop0 needs it for the delay slot/cop bits
+  Flush(FLUSH_FOR_BREAKPOINT);
+
+  // cop0 has to come first, because debug can exit execution
+  if (iinfo->is_cop0_breakpoint)
+  {
+    // cop0 always exits regardless of what the debug bp does
+    cg->call(&CPU::DispatchCop0ExecutionBreakpoint);
+    if (iinfo->is_debug_breakpoint)
+      cg->call(&CPU::DispatchDebugBreakpoint);
+    EndBlock(std::nullopt, true);
+    return true;
+  }
+
+  // only a debug bp?
+  if (iinfo->is_debug_breakpoint)
+  {
+    // debug may or may not exit execution, or change pc
+    cg->call(&CPU::DispatchDebugBreakpoint);
+    cg->test(cg->eax, cg->eax);
+    SwitchToFarCode(true, &CodeGenerator::jnz);
+    BackupHostState();
+    EndBlock(std::nullopt, true);
+    RestoreHostState();
+    SwitchToNearCode(false);
+  }
+
+  // we can continue
+  return true;
+}
+
 void CPU::X64Recompiler::CheckBranchTarget(const Xbyak::Reg32& pcreg)
 {
   if (!g_settings.cpu_recompiler_memory_exceptions)
@@ -2289,16 +2328,26 @@ void CPU::X64Recompiler::Compile_mtc0(CompileFlags cf)
     cg->mov(RWARG1, cg->dword[PTR(&g_state.cop0_regs.sr.bits)]);
     TestInterrupts(RWARG1);
   }
-  else if (reg == Cop0Reg::DCIC || reg == Cop0Reg::BPCM)
+  else if (reg == Cop0Reg::DCIC || reg == Cop0Reg::BPC || reg == Cop0Reg::BPCM)
   {
     // need to check whether we're switching to debug mode
     Flush(FLUSH_FOR_C_CALL);
+
+    // dcic can enable data breakpoints
+    if (reg == Cop0Reg::DCIC)
+    {
       cg->call(&CPU::UpdateDebugDispatcherFlag);
       cg->test(cg->al, cg->al);
       SwitchToFarCode(true, &Xbyak::CodeGenerator::jnz);
+      SwitchToNearCode(false);
+    }
+
+    cg->call(&CPU::AreCop0ExecutionBreakpointsActive);
+    cg->test(cg->al, cg->al);
+    SwitchToFarCode(true, &Xbyak::CodeGenerator::jnz);
     BackupHostState();
     Flush(FLUSH_FOR_EARLY_BLOCK_EXIT);
-    cg->call(&CPU::ExitExecution); // does not return
+    cg->call(&CodeCache::ResetAndExitExecution); // does not return
     RestoreHostState();
     SwitchToNearCode(false);
   }

src/core/cpu_recompiler_x64.h

@@ -51,6 +51,8 @@ protected:
 
   void Compile_Fallback() override;
 
+  bool CompileExecutionBreakpointCheck() override;
+
   void CheckBranchTarget(const Xbyak::Reg32& pcreg);
   void Compile_jr(CompileFlags cf) override;
   void Compile_jalr(CompileFlags cf) override;