factor out CheckPendingCacheReset

src/hw/sh4/sh4.cc

@@ -36,7 +36,6 @@ SH4::SH4(Dreamcast *dc)
       MemoryInterface(this),
       dc_(dc),
       code_cache_(nullptr),
-      pending_cache_reset_(false),
       requested_interrupts_(0),
       pending_interrupts_(0),
       tmu_timers_{INVALID_TIMER, INVALID_TIMER, INVALID_TIMER},
@@ -100,7 +99,6 @@ void SH4::Run(const std::chrono::nanoseconds &delta) {
     SH4BlockEntry *block = code_cache_->GetBlock(ctx_.pc);
     ctx_.pc = block->run();
 
-    CheckPendingCacheReset();
     CheckPendingInterrupts();
   }
 
@@ -147,7 +145,7 @@ int SH4::NumRegisters() { return 59; }
 
 void SH4::Step() {
   // invalidate the block for the current pc
-  code_cache_->InvalidateBlocks(ctx_.pc);
+  code_cache_->RemoveBlocks(ctx_.pc);
 
   // recompile it with only one instruction and run it
   SH4BlockEntry *block = code_cache_->CompileBlock(ctx_.pc, 1);
@@ -165,7 +163,7 @@ void SH4::AddBreakpoint(int type, uint32_t addr) {
   // write out an invalid instruction
   memory_->W16(addr, 0);
 
-  code_cache_->InvalidateBlocks(addr);
+  code_cache_->RemoveBlocks(addr);
 }
 
 void SH4::RemoveBreakpoint(int type, uint32_t addr) {
@@ -178,7 +176,7 @@ void SH4::RemoveBreakpoint(int type, uint32_t addr) {
   // overwrite the invalid instruction with the original
   memory_->W16(addr, instr);
 
-  code_cache_->InvalidateBlocks(addr);
+  code_cache_->RemoveBlocks(addr);
 }
 
 void SH4::ReadMemory(uint32_t addr, uint8_t *buffer, int size) {
@@ -550,17 +548,9 @@ void SH4::ResetCache() {
   // to
   // the P0, P1, P3, or U0 area should be located at least eight instructions
   // after the CCR update instruction."
-  pending_cache_reset_ = true;
-}
+  LOG_INFO("Reset instruction cache");
 
-inline void SH4::CheckPendingCacheReset() {
-  if (!pending_cache_reset_) {
-    return;
-  }
-
-  code_cache_->ResetBlocks();
-
-  pending_cache_reset_ = false;
+  code_cache_->UnlinkBlocks();
 }
 
 //

src/hw/sh4/sh4.h

@@ -172,7 +172,6 @@ class SH4 : public Device,
 
   // CCN
   void ResetCache();
-  void CheckPendingCacheReset();
 
   // INTC
   void ReprioritizeInterrupts();
@@ -200,8 +199,6 @@ class SH4 : public Device,
 #include "hw/sh4/sh4_regs.inc"
 #undef SH4_REG
 
-  bool pending_cache_reset_;
-
   Interrupt sorted_interrupts_[NUM_INTERRUPTS];
   uint64_t sort_id_[NUM_INTERRUPTS];
   uint64_t priority_mask_[16];

src/hw/sh4/sh4_code_cache.cc

@@ -98,8 +98,8 @@ SH4BlockEntry *SH4CodeCache::CompileBlock(uint32_t addr, int max_instrs) {
   if (!run) {
     LOG_INFO("Assembler overflow, resetting block cache");
 
-    // the backend overflowed, reset the block cache
-    ResetBlocks();
+    // the backend overflowed, completely clear the block cache
+    ClearBlocks();
 
     // if the backend fails to assemble on an empty cache, there's nothing to be
     // done
@@ -124,8 +124,7 @@ SH4BlockEntry *SH4CodeCache::CompileBlock(uint32_t addr, int max_instrs) {
 
   return block;
 }
-
-void SH4CodeCache::InvalidateBlocks(uint32_t addr) {
+void SH4CodeCache::RemoveBlocks(uint32_t addr) {
   // remove any block which overlaps the address
   while (true) {
     SH4BlockEntry *block = LookupBlock(addr);
@@ -146,8 +145,19 @@ void SH4CodeCache::InvalidateBlocks(uint32_t addr) {
   }
 }
 
-void SH4CodeCache::ResetBlocks() {
-  // reset block cache
+void SH4CodeCache::UnlinkBlocks() {
+  // unlink the block pointers, but don't remove the map entries. this is used
+  // when clearing the cache while a block is currently executing
+  for (int i = 0; i < MAX_BLOCKS; i++) {
+    SH4BlockEntry *block = &blocks_[i];
+    block->run = default_block_;
+    block->flags = 0;
+  }
+}
+
+void SH4CodeCache::ClearBlocks() {
+  // unlink all block pointers and remove all map entries. this is only safe to
+  // use when no blocks are currently executing
   for (int i = 0; i < MAX_BLOCKS; i++) {
     SH4BlockEntry *block = &blocks_[i];
     block->run = default_block_;
@@ -158,7 +168,7 @@ void SH4CodeCache::ResetBlocks() {
   block_map_.clear();
   reverse_block_map_.clear();
 
-  // have the backend reset its codegen buffers
+  // have the backend reset its codegen buffers as well
   backend_->Reset();
 }
 
@@ -176,11 +186,10 @@ bool SH4CodeCache::HandleException(void *ctx, Exception &ex) {
     return false;
   }
 
-  // exception was handled, reset the block pointer back to the default compile
-  // handler and flag the block to be recompiled without fastmem optimizations
-  // on the next access. note, the block can't be removed from the lookup maps
-  // at this point because blocks may trigger multiple exceptions before being
-  // recompiled
+  // exception was handled, unlink the block pointer and flag the block to be
+  // recompiled without fastmem optimizations on the next access. note, the
+  // block can't be removed from the lookup maps at this point because it's
+  // still executing and may trigger subsequent exceptions
   block->run = self->default_block_;
   block->flags |= BF_SLOWMEM;
 

src/hw/sh4/sh4_code_cache.h

@@ -58,8 +58,9 @@ class SH4CodeCache {
     return &blocks_[offset];
   }
   SH4BlockEntry *CompileBlock(uint32_t addr, int max_instrs);
-  void InvalidateBlocks(uint32_t addr);
-  void ResetBlocks();
+  void RemoveBlocks(uint32_t addr);
+  void UnlinkBlocks();
+  void ClearBlocks();
 
  private:
   static bool HandleException(void *ctx, sys::Exception &ex);