CPU/Recompiler/AArch32: Load membase on demand

src/core/cpu_newrec_compiler_aarch64.cpp

@@ -382,7 +382,6 @@ void CPU::NewRec::AArch64Compiler::EndAndLinkBlock(const std::optional<u32>& new
   DebugAssert(!m_dirty_pc);
 
   // TODO: try extracting this to a function
-  // TODO: move the cycle flush in here..
 
   // save cycles for event test
   const TickCount cycles = std::exchange(m_cycles, 0);
@@ -621,7 +620,12 @@ void CPU::NewRec::AArch64Compiler::Flush(u32 flags)
   if (flags & FLUSH_INSTRUCTION_BITS)
   {
     // This sucks, but it's only used for fallbacks.
-    Panic("Not implemented");
+    EmitMov(RWARG1, inst->bits);
+    EmitMov(RWARG2, m_current_instruction_pc);
+    EmitMov(RWARG3, m_current_instruction_branch_delay_slot);
+    armAsm->str(RWARG1, PTR(&g_state.current_instruction.bits));
+    armAsm->str(RWARG2, PTR(&g_state.current_instruction_pc));
+    armAsm->strb(RWARG3, PTR(&g_state.current_instruction_in_branch_delay_slot));
   }
 
   if (flags & FLUSH_LOAD_DELAY_FROM_STATE && m_load_delay_dirty)
@@ -699,26 +703,23 @@ void CPU::NewRec::AArch64Compiler::Compile_Fallback()
 {
   Flush(FLUSH_FOR_INTERPRETER);
 
-#if 0
+  EmitCall(armAsm, &CPU::Recompiler::Thunks::InterpretInstruction);
-  cg->call(&CPU::Recompiler::Thunks::InterpretInstruction);
 
   // TODO: make me less garbage
   // TODO: this is wrong, it flushes the load delay on the same cycle when we return.
   // but nothing should be going through here..
   Label no_load_delay;
-  cg->movzx(RWARG1, cg->byte[PTR(&g_state.next_load_delay_reg)]);
+  armAsm->ldrb(RWARG1, PTR(&g_state.next_load_delay_reg));
-  cg->cmp(RWARG1, static_cast<u8>(Reg::count));
+  armAsm->cmp(RWARG1, static_cast<u8>(Reg::count));
-  cg->je(no_load_delay, CodeGenerator::T_SHORT);
+  armAsm->b(&no_load_delay, eq);
-  cg->mov(RWARG2, cg->dword[PTR(&g_state.next_load_delay_value)]);
+  armAsm->ldr(RWARG2, PTR(&g_state.next_load_delay_value));
-  cg->mov(cg->byte[PTR(&g_state.load_delay_reg)], RWARG1);
+  armAsm->strb(RWARG1, PTR(&g_state.load_delay_reg));
-  cg->mov(cg->dword[PTR(&g_state.load_delay_value)], RWARG2);
+  armAsm->str(RWARG2, PTR(&g_state.load_delay_value));
-  cg->mov(cg->byte[PTR(&g_state.next_load_delay_reg)], static_cast<u32>(Reg::count));
+  EmitMov(RWARG1, static_cast<u32>(Reg::count));
-  cg->L(no_load_delay);
+  armAsm->strb(RWARG1, PTR(&g_state.next_load_delay_reg));
+  armAsm->bind(&no_load_delay);
 
   m_load_delay_dirty = EMULATE_LOAD_DELAYS;
-#else
-  Panic("Fixme");
-#endif
 }
 
 void CPU::NewRec::AArch64Compiler::CheckBranchTarget(const vixl::aarch64::WRegister& pcreg)

src/core/cpu_recompiler_code_generator.h

@@ -122,6 +122,7 @@ public:
                                    const Value& address, RegSize size, const Value& value);
   void EmitStoreGuestMemorySlowmem(Instruction instruction, const CodeCache::InstructionInfo& info,
                                    const Value& address, RegSize size, const Value& value, bool in_far_code);
+  void EnsureMembaseLoaded();
   void EmitUpdateFastmemBase();
 
   // Unconditional branch to pointer. May allocate a scratch register.
@@ -291,6 +292,7 @@ private:
   bool m_load_delay_dirty = false;
   bool m_next_load_delay_dirty = false;
   bool m_gte_busy_cycles_dirty = false;
+  bool m_membase_loaded = false;
 
   //////////////////////////////////////////////////////////////////////////
   // Speculative Constants

src/core/cpu_recompiler_code_generator_aarch32.cpp

@@ -224,13 +224,12 @@ u32 CPU::CodeCache::EmitASMFunctions(void* code, u32 code_size)
 #undef RARG3
 #undef RARG4
 #undef RSCRATCH
-#undef RMEMBASE
 #undef RSTATE
 
 namespace CPU::Recompiler {
 
 constexpr HostReg RCPUPTR = 4;
-constexpr HostReg RMEMBASEPTR = 5;
+constexpr HostReg RMEMBASEPTR = 3;
 constexpr HostReg RRETURN = 0;
 constexpr HostReg RARG1 = 0;
 constexpr HostReg RARG2 = 1;
@@ -385,14 +384,6 @@ void CodeGenerator::EmitBeginBlock(bool allocate_registers /* = true */)
     // m_emit->Mov(GetCPUPtrReg(), reinterpret_cast<uintptr_t>(&g_state));
     DebugAssert(cpu_reg_allocated);
     UNREFERENCED_VARIABLE(cpu_reg_allocated);
-
-    // If there's loadstore instructions, preload the fastmem base.
-    if (m_block->HasFlag(CodeCache::BlockFlags::ContainsLoadStoreInstructions))
-    {
-      const bool fastmem_reg_allocated = m_register_cache.AllocateHostReg(RMEMBASEPTR);
-      Assert(fastmem_reg_allocated);
-      m_emit->Ldr(GetFastmemBasePtrReg(), a32::MemOperand(GetCPUPtrReg(), offsetof(State, fastmem_base)));
-    }
   }
 }
 
@@ -400,9 +391,6 @@ void CodeGenerator::EmitEndBlock(bool free_registers /* = true */, const void* j
 {
   if (free_registers)
   {
-    if (m_block->HasFlag(CodeCache::BlockFlags::ContainsLoadStoreInstructions))
-      m_register_cache.FreeHostReg(RMEMBASEPTR);
-
     m_register_cache.FreeHostReg(RCPUPTR);
     m_register_cache.FreeHostReg(14);
     m_register_cache.PopCalleeSavedRegisters(true);
@@ -1058,6 +1046,7 @@ void CodeGenerator::EmitSetConditionResult(HostReg to_reg, RegSize to_size, Cond
 u32 CodeGenerator::PrepareStackForCall()
 {
   m_register_cache.PushCallerSavedRegisters();
+  m_membase_loaded = false;
   return 0;
 }
 
@@ -1351,13 +1340,24 @@ void CodeGenerator::EmitAddCPUStructField(u32 offset, const Value& value)
   }
 }
 
+void CodeGenerator::EnsureMembaseLoaded()
+{
+  if (m_membase_loaded)
+    return;
+
+  m_emit->Ldr(GetFastmemBasePtrReg(), a32::MemOperand(GetCPUPtrReg(), offsetof(State, fastmem_base)));
+  m_membase_loaded = true;
+}
+
 void CodeGenerator::EmitUpdateFastmemBase()
 {
-  m_emit->Ldr(GetFastmemBasePtrReg(), a32::MemOperand(GetCPUPtrReg(), offsetof(State, fastmem_base)));
+  m_membase_loaded = false;
 }
 
 void CodeGenerator::EmitLoadGuestRAMFastmem(const Value& address, RegSize size, Value& result)
 {
+  EnsureMembaseLoaded();
+
   HostReg address_reg;
   if (address.IsConstant())
   {
@@ -1396,6 +1396,8 @@ void CodeGenerator::EmitLoadGuestRAMFastmem(const Value& address, RegSize size,
 void CodeGenerator::EmitLoadGuestMemoryFastmem(Instruction instruction, const CodeCache::InstructionInfo& info,
                                                const Value& address, RegSize size, Value& result)
 {
+  EnsureMembaseLoaded();
+
   HostReg address_reg;
   if (address.IsConstant())
   {
@@ -1538,6 +1540,8 @@ void CodeGenerator::EmitLoadGuestMemorySlowmem(Instruction instruction, const Co
 void CodeGenerator::EmitStoreGuestMemoryFastmem(Instruction instruction, const CodeCache::InstructionInfo& info,
                                                 const Value& address, RegSize size, const Value& value)
 {
+  EnsureMembaseLoaded();
+
   Value actual_value = GetValueInHostRegister(value);
 
   HostReg address_reg;

src/core/cpu_recompiler_types.h

@@ -84,7 +84,6 @@ constexpr u32 MAX_FAR_HOST_BYTES_PER_INSTRUCTION = 128;
 #define RARG4 vixl::aarch32::r3
 #define RSCRATCH vixl::aarch32::r12
 #define RSTATE vixl::aarch32::r4
-#define RMEMBASE vixl::aarch32::r5
 
 s32 armGetPCDisplacement(const void* current, const void* target);
 bool armIsPCDisplacementInImmediateRange(s32 displacement);