JIT fixes

- fix fastmem problems on linux
- small fix memory leak
- SlowWrite functions always take in a 32-bit variable so that the C compiler knows that the values aren't necessary zero extended
- a few other stylistic things
- handle SIGBUS as well (for macos)

8 files changed, 140 insertions, 91 deletions

diff --git a/src/ARMJIT.cpp b/src/ARMJIT.cpp
index 82f1d79..1921f13 100644
--- a/src/ARMJIT.cpp
+++ b/src/ARMJIT.cpp
@@ -176,7 +176,7 @@ T SlowRead9(u32 addr, ARMv5* cpu)
 }
 
 template <typename T, int ConsoleType>
-void SlowWrite9(u32 addr, ARMv5* cpu, T val)
+void SlowWrite9(u32 addr, ARMv5* cpu, u32 val)
 {
     addr &= ~(sizeof(T) - 1);
 
@@ -224,7 +224,7 @@ T SlowRead7(u32 addr)
 }
 
 template <typename T, int ConsoleType>
-void SlowWrite7(u32 addr, T val)
+void SlowWrite7(u32 addr, u32 val)
 {
     addr &= ~(sizeof(T) - 1);
 
@@ -266,16 +266,16 @@ void SlowBlockTransfer7(u32 addr, u64* data, u32 num)
 
 #define INSTANTIATE_SLOWMEM(consoleType) \
     template void SlowWrite9<u32, consoleType>(u32, ARMv5*, u32); \
-    template void SlowWrite9<u16, consoleType>(u32, ARMv5*, u16); \
-    template void SlowWrite9<u8, consoleType>(u32, ARMv5*, u8); \
+    template void SlowWrite9<u16, consoleType>(u32, ARMv5*, u32); \
+    template void SlowWrite9<u8, consoleType>(u32, ARMv5*, u32); \
     \
     template u32 SlowRead9<u32, consoleType>(u32, ARMv5*); \
     template u16 SlowRead9<u16, consoleType>(u32, ARMv5*); \
     template u8 SlowRead9<u8, consoleType>(u32, ARMv5*); \
     \
     template void SlowWrite7<u32, consoleType>(u32, u32); \
-    template void SlowWrite7<u16, consoleType>(u32, u16); \
-    template void SlowWrite7<u8, consoleType>(u32, u8); \
+    template void SlowWrite7<u16, consoleType>(u32, u32); \
+    template void SlowWrite7<u8, consoleType>(u32, u32); \
     \
     template u32 SlowRead7<u32, consoleType>(u32); \
     template u16 SlowRead7<u16, consoleType>(u32); \
@@ -298,6 +298,7 @@ void Init()
 
 void DeInit()
 {
+    ResetBlockCache();
     ARMJIT_Memory::DeInit();
 
     delete JITCompiler;
@@ -1117,6 +1118,7 @@ void ResetBlockCache()
             range->Blocks.Clear();
             range->Code = 0;
         }
+        delete block;
     }
     JitBlocks9.clear();
     JitBlocks7.clear();
diff --git a/src/ARMJIT_A64/ARMJIT_Compiler.h b/src/ARMJIT_A64/ARMJIT_Compiler.h
index ef40ea4..a79e9da 100644
--- a/src/ARMJIT_A64/ARMJIT_Compiler.h
+++ b/src/ARMJIT_A64/ARMJIT_Compiler.h
@@ -214,8 +214,8 @@ public:
         return (u8*)entry - GetRXBase();
     }
 
-    bool IsJITFault(u64 pc);
-    s64 RewriteMemAccess(u64 pc);
+    bool IsJITFault(u8* pc);
+    u8* RewriteMemAccess(u8* pc);
 
     void SwapCodeRegion()
     {
diff --git a/src/ARMJIT_A64/ARMJIT_LoadStore.cpp b/src/ARMJIT_A64/ARMJIT_LoadStore.cpp
index 86e257a..2c14dc6 100644
--- a/src/ARMJIT_A64/ARMJIT_LoadStore.cpp
+++ b/src/ARMJIT_A64/ARMJIT_LoadStore.cpp
@@ -9,37 +9,34 @@ using namespace Arm64Gen;
 namespace ARMJIT
 {
 
-bool Compiler::IsJITFault(u64 pc)
+bool Compiler::IsJITFault(u8* pc)
 {
-    return pc >= (u64)GetRXBase() && pc - (u64)GetRXBase() < (JitMemMainSize + JitMemSecondarySize);
+    return (u64)pc >= (u64)GetRXBase() && (u64)pc - (u64)GetRXBase() < (JitMemMainSize + JitMemSecondarySize);
 }
 
-s64 Compiler::RewriteMemAccess(u64 pc)
+u8* Compiler::RewriteMemAccess(u8* pc)
 {
-    ptrdiff_t pcOffset = pc - (u64)GetRXBase();
+    ptrdiff_t pcOffset = pc - GetRXBase();
 
     auto it = LoadStorePatches.find(pcOffset);
 
     if (it != LoadStorePatches.end())
     {
         LoadStorePatch patch = it->second;
+        LoadStorePatches.erase(it);
 
         ptrdiff_t curCodeOffset = GetCodeOffset();
 
         SetCodePtrUnsafe(pcOffset + patch.PatchOffset);
 
         BL(patch.PatchFunc);
-
         for (int i = 0; i < patch.PatchSize / 4 - 1; i++)
             HINT(HINT_NOP);
-
         FlushIcacheSection((u8*)pc + patch.PatchOffset, (u8*)GetRXPtr());
 
         SetCodePtrUnsafe(curCodeOffset);
 
-        LoadStorePatches.erase(it);
-
-        return patch.PatchOffset;
+        return pc + (ptrdiff_t)patch.PatchOffset;
     }
     printf("this is a JIT bug! %08x\n", __builtin_bswap32(*(u32*)pc));
     abort();
@@ -192,7 +189,7 @@ void Compiler::Comp_MemAccess(int rd, int rn, Op2 offset, int size, int flags)
         else
         {
             LDRGeneric(size, flags & memop_SignExtend, rdMapped, size > 8 ? X1 : X0, X7);
-            if (size == 32)
+            if (size == 32 && !addrIsStatic)
             {
                 UBFIZ(W0, W0, 3, 2);
                 RORV(rdMapped, rdMapped, W0);
diff --git a/src/ARMJIT_Internal.h b/src/ARMJIT_Internal.h
index 4244470..b1e35f5 100644
--- a/src/ARMJIT_Internal.h
+++ b/src/ARMJIT_Internal.h
@@ -216,9 +216,9 @@ template <u32 Num>
 void LinkBlock(ARM* cpu, u32 codeOffset);
 
 template <typename T, int ConsoleType> T SlowRead9(u32 addr, ARMv5* cpu);
-template <typename T, int ConsoleType> void SlowWrite9(u32 addr, ARMv5* cpu, T val);
+template <typename T, int ConsoleType> void SlowWrite9(u32 addr, ARMv5* cpu, u32 val);
 template <typename T, int ConsoleType> T SlowRead7(u32 addr);
-template <typename T, int ConsoleType> void SlowWrite7(u32 addr, T val);
+template <typename T, int ConsoleType> void SlowWrite7(u32 addr, u32 val);
 
 template <bool Write, int ConsoleType> void SlowBlockTransfer9(u32 addr, u64* data, u32 num, ARMv5* cpu);
 template <bool Write, int ConsoleType> void SlowBlockTransfer7(u32 addr, u64* data, u32 num);
diff --git a/src/ARMJIT_Memory.cpp b/src/ARMJIT_Memory.cpp
index d321d2f..355031e 100644
--- a/src/ARMJIT_Memory.cpp
+++ b/src/ARMJIT_Memory.cpp
@@ -40,7 +40,8 @@
     We handle this by only mapping those regions which are actually
     used and by praying the games don't go wild.
 
-    Beware, this file is full of platform specific code.
+    Beware, this file is full of platform specific code and copied
+    from Dolphin, so enjoy the copied comments!
 
 */
 
@@ -49,10 +50,10 @@ namespace ARMJIT_Memory
 struct FaultDescription
 {
     u32 EmulatedFaultAddr;
-    u64 FaultPC;
+    u8* FaultPC;
 };
 
-bool FaultHandler(FaultDescription* faultDesc, s32& offset);
+bool FaultHandler(FaultDescription& faultDesc);
 }
 
 #if defined(__SWITCH__)
@@ -75,7 +76,7 @@ void __libnx_exception_handler(ThreadExceptionDump* ctx)
     ARMJIT_Memory::FaultDescription desc;
     u8* curArea = (u8*)(NDS::CurCPU == 0 ? ARMJIT_Memory::FastMem9Start : ARMJIT_Memory::FastMem7Start);
     desc.EmulatedFaultAddr = (u8*)ctx->far.x - curArea;
-    desc.FaultPC = ctx->pc.x;
+    desc.FaultPC = (u8*)ctx->pc.x;
 
     u64 integerRegisters[33];
     memcpy(integerRegisters, &ctx->cpu_gprs[0].x, 8*29);
@@ -84,10 +85,9 @@ void __libnx_exception_handler(ThreadExceptionDump* ctx)
     integerRegisters[31] = ctx->sp.x;
     integerRegisters[32] = ctx->pc.x;
 
-    s32 offset;
-    if (ARMJIT_Memory::FaultHandler(&desc, offset))
+    if (ARMJIT_Memory::FaultHandler(desc, offset))
     {
-        integerRegisters[32] += offset;
+        integerRegisters[32] = (u64)desc.FaultPC;
 
         ARM_RestoreContext(integerRegisters);	
     }
@@ -117,12 +117,11 @@ static LONG ExceptionHandler(EXCEPTION_POINTERS* exceptionInfo)
     ARMJIT_Memory::FaultDescription desc;
     u8* curArea = (u8*)(NDS::CurCPU == 0 ? ARMJIT_Memory::FastMem9Start : ARMJIT_Memory::FastMem7Start);
     desc.EmulatedFaultAddr = (u8*)exceptionInfo->ExceptionRecord->ExceptionInformation[1] - curArea;
-    desc.FaultPC = exceptionInfo->ContextRecord->Rip;
+    desc.FaultPC = (u8*)exceptionInfo->ContextRecord->Rip;
 
-    s32 offset = 0;
-    if (ARMJIT_Memory::FaultHandler(&desc, offset))
+    if (ARMJIT_Memory::FaultHandler(desc))
     {
-        exceptionInfo->ContextRecord->Rip += offset;
+        exceptionInfo->ContextRecord->Rip = (u8*)desc.FaultPC;
         return EXCEPTION_CONTINUE_EXECUTION;
     }
 
@@ -131,50 +130,66 @@ static LONG ExceptionHandler(EXCEPTION_POINTERS* exceptionInfo)
 
 #else
 
-struct sigaction NewSa;
-struct sigaction OldSa;
+static struct sigaction OldSaSegv;
+static struct sigaction OldSaBus;
 
 static void SigsegvHandler(int sig, siginfo_t* info, void* rawContext)
 {
+    if (sig != SIGSEGV && sig != SIGBUS)
+    {
+        // We are not interested in other signals - handle it as usual.
+        return;
+    }
+    if (info->si_code != SEGV_MAPERR && info->si_code != SEGV_ACCERR)
+    {
+        // Huh? Return.
+        return;
+    }
+
     ucontext_t* context = (ucontext_t*)rawContext;
-    
+
     ARMJIT_Memory::FaultDescription desc;
     u8* curArea = (u8*)(NDS::CurCPU == 0 ? ARMJIT_Memory::FastMem9Start : ARMJIT_Memory::FastMem7Start);
 #ifdef __x86_64__
     desc.EmulatedFaultAddr = (u8*)info->si_addr - curArea;
-    desc.FaultPC = context->uc_mcontext.gregs[REG_RIP];
+    desc.FaultPC = (u8*)context->uc_mcontext.gregs[REG_RIP];
 #else
     desc.EmulatedFaultAddr = (u8*)context->uc_mcontext.fault_address - curArea;
-    desc.FaultPC = context->uc_mcontext.pc;
+    desc.FaultPC = (u8*)context->uc_mcontext.pc;
 #endif
 
-    s32 offset = 0;
-    if (ARMJIT_Memory::FaultHandler(&desc, offset))
+    if (ARMJIT_Memory::FaultHandler(desc))
     {
 #ifdef __x86_64__
-        context->uc_mcontext.gregs[REG_RIP] += offset;
+        context->uc_mcontext.gregs[REG_RIP] = (u64)desc.FaultPC;
 #else
-        context->uc_mcontext.pc += offset;
+        context->uc_mcontext.pc = (u64)desc.FaultPC;
 #endif
         return;
     }
 
-    if (OldSa.sa_flags & SA_SIGINFO)
+    struct sigaction* oldSa;
+    if (sig == SIGSEGV)
+      oldSa = &OldSaSegv;
+    else
+      oldSa = &OldSaBus;
+
+    if (oldSa->sa_flags & SA_SIGINFO)
     {
-      OldSa.sa_sigaction(sig, info, rawContext);
+      oldSa->sa_sigaction(sig, info, rawContext);
       return;
     }
-    if (OldSa.sa_handler == SIG_DFL)
+    if (oldSa->sa_handler == SIG_DFL)
     {
       signal(sig, SIG_DFL);
       return;
     }
-    if (OldSa.sa_handler == SIG_IGN)
+    if (oldSa->sa_handler == SIG_IGN)
     {
       // Ignore signal
       return;
     }
-    OldSa.sa_handler(sig);
+    oldSa->sa_handler(sig);
 }
 
 #endif
@@ -231,7 +246,7 @@ enum
 {
     memstate_Unmapped,
     memstate_MappedRW,
-    // on switch this is unmapped as well
+    // on Switch this is unmapped as well
     memstate_MappedProtected,
 };
 
@@ -505,6 +520,21 @@ bool MapAtAddress(u32 addr)
     bool isExecutable = ARMJIT::CodeMemRegions[region];
 
 #ifndef __SWITCH__
+    if (num == 0)
+    {
+        // if a DTCM mapping is mapped before the mapping below it
+        // we unmap it, so it won't just be overriden
+        for (int i = 0; i < Mappings[memregion_DTCM].Length; i++)
+        {
+            Mapping& mapping = Mappings[memregion_DTCM][i];
+            if (mirrorStart < mapping.Addr + mapping.Size && mirrorStart + mirrorSize >= mapping.Addr)
+            {
+                mapping.Unmap(memregion_DTCM);
+            }
+        }
+        Mappings[memregion_DTCM].Clear();
+    }
+
     bool succeded = MapIntoRange(mirrorStart, num, OffsetsPerRegion[region] + memoryOffset, mirrorSize);
     assert(succeded);
 #endif
@@ -562,21 +592,20 @@ bool MapAtAddress(u32 addr)
     return true;
 }
 
-bool FaultHandler(FaultDescription* faultDesc, s32& offset)
+bool FaultHandler(FaultDescription& faultDesc)
 {
-    if (ARMJIT::JITCompiler->IsJITFault(faultDesc->FaultPC))
+    if (ARMJIT::JITCompiler->IsJITFault(faultDesc.FaultPC))
     {
         bool rewriteToSlowPath = true;
 
-        u32 addr = faultDesc->EmulatedFaultAddr;
+        u8* memStatus = NDS::CurCPU == 0 ? MappingStatus9 : MappingStatus7;
 
-        if ((NDS::CurCPU == 0 ? MappingStatus9 : MappingStatus7)[addr >> 12] == memstate_Unmapped)
-            rewriteToSlowPath = !MapAtAddress(faultDesc->EmulatedFaultAddr);
+        if (memStatus[faultDesc.EmulatedFaultAddr >> 12] == memstate_Unmapped)
+            rewriteToSlowPath = !MapAtAddress(faultDesc.EmulatedFaultAddr);
 
         if (rewriteToSlowPath)
-        {
-            offset = ARMJIT::JITCompiler->RewriteMemAccess(faultDesc->FaultPC);
-        }
+            faultDesc.FaultPC = ARMJIT::JITCompiler->RewriteMemAccess(faultDesc.FaultPC);
+
         return true;
     }
     return false;
@@ -624,22 +653,28 @@ void Init()
 
     u8* basePtr = MemoryBase;
 #else
-    FastMem9Start = mmap(NULL, AddrSpaceSize, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
-    FastMem7Start = mmap(NULL, AddrSpaceSize, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
-
-    MemoryBase = (u8*)mmap(NULL, MemoryTotalSize, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
+    // this used to be allocated with three different mmaps
+    // The idea was to give the OS more freedom where to position the buffers, 
+    // but something was bad about this so instead we take this vmem eating monster
+    // which seems to work better.
+    MemoryBase = (u8*)mmap(NULL, AddrSpaceSize*4, PROT_NONE, MAP_ANON | MAP_PRIVATE, -1, 0);
+    munmap(MemoryBase, AddrSpaceSize*4);
+    FastMem9Start = MemoryBase;
+    FastMem7Start = MemoryBase + AddrSpaceSize;
+    MemoryBase = MemoryBase + AddrSpaceSize*2;
 
     MemoryFile = memfd_create("melondsfastmem", 0);
     ftruncate(MemoryFile, MemoryTotalSize);
 
-    NewSa.sa_flags = SA_SIGINFO;
-    sigemptyset(&NewSa.sa_mask);
-    NewSa.sa_sigaction = SigsegvHandler;
-    sigaction(SIGSEGV, &NewSa, &OldSa);
-
-    munmap(MemoryBase, MemoryTotalSize);
-    munmap(FastMem9Start, AddrSpaceSize);
-    munmap(FastMem7Start, AddrSpaceSize);
+    struct sigaction sa;
+    sa.sa_handler = nullptr;
+    sa.sa_sigaction = &SigsegvHandler;
+    sa.sa_flags = SA_SIGINFO;
+    sigemptyset(&sa.sa_mask);
+    sigaction(SIGSEGV, &sa, &OldSaSegv);
+#ifdef __APPLE__
+    sigaction(SIGBUS, &sa, &OldSaBus);
+#endif
 
     mmap(MemoryBase, MemoryTotalSize, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, MemoryFile, 0);
 
@@ -657,8 +692,8 @@ void Init()
 void DeInit()
 {
 #if defined(__SWITCH__)
-    virtmemFree(FastMem9Start, 0x100000000);
-    virtmemFree(FastMem7Start, 0x100000000);
+    virtmemFree(FastMem9Start, AddrSpaceSize);
+    virtmemFree(FastMem7Start, AddrSpaceSize);
 
     svcUnmapProcessCodeMemory(envGetOwnProcessHandle(), (u64)MemoryBaseCodeMem, (u64)MemoryBase, MemoryTotalSize);
     virtmemFree(MemoryBaseCodeMem, MemoryTotalSize);
@@ -668,6 +703,14 @@ void DeInit()
     CloseHandle(MemoryFile);
 
     RemoveVectoredExceptionHandler(ExceptionHandlerHandle);
+#else
+    sigaction(SIGSEGV, &OldSaSegv, nullptr);
+#ifdef __APPLE__
+    sigaction(SIGBUS, &OldSaBus, nullptr);
+#endif
+
+    munmap(MemoryBase, MemoryTotalSize);
+    close(MemoryFile);
 #endif
 }
 
@@ -702,7 +745,15 @@ bool IsFastmemCompatible(int region)
         || region == memregion_NewSharedWRAM_C)
         return false;
 #endif
-    return OffsetsPerRegion[region] != UINT32_MAX;
+    if (region == memregion_DTCM
+        || region == memregion_MainRAM
+        || region == memregion_NewSharedWRAM_A
+        || region == memregion_NewSharedWRAM_B
+        || region == memregion_NewSharedWRAM_C
+        || region == memregion_SharedWRAM)
+        return false;
+    //return OffsetsPerRegion[region] != UINT32_MAX;
+    return false;
 }
 
 bool GetMirrorLocation(int region, u32 num, u32 addr, u32& memoryOffset, u32& mirrorStart, u32& mirrorSize)
@@ -997,9 +1048,11 @@ int ClassifyAddress7(u32 addr)
         case 0x06000000:
         case 0x06800000:
             return memregion_VWRAM;
+
+        default:
+            return memregion_Other;
         }
     }
-    return memregion_Other;
 }
 
 void WifiWrite32(u32 addr, u32 val)
diff --git a/src/ARMJIT_x64/ARMJIT_Compiler.cpp b/src/ARMJIT_x64/ARMJIT_Compiler.cpp
index 9785ffc..076f48c 100644
--- a/src/ARMJIT_x64/ARMJIT_Compiler.cpp
+++ b/src/ARMJIT_x64/ARMJIT_Compiler.cpp
@@ -345,7 +345,7 @@ Compiler::Compiler()
                     ABI_PushRegistersAndAdjustStack(CallerSavedPushRegs, 8);
                     if (consoleType == 0)
                     {
-                        switch ((8 << size) |  num)
+                        switch ((8 << size) | num)
                         {
                         case 32: ABI_CallFunction(SlowWrite9<u32, 0>); break;
                         case 33: ABI_CallFunction(SlowWrite7<u32, 0>); break;
@@ -357,7 +357,7 @@ Compiler::Compiler()
                     }
                     else
                     {
-                        switch ((8 << size) |  num)
+                        switch ((8 << size) | num)
                         {
                         case 32: ABI_CallFunction(SlowWrite9<u32, 1>); break;
                         case 33: ABI_CallFunction(SlowWrite7<u32, 1>); break;
@@ -380,7 +380,7 @@ Compiler::Compiler()
                         ABI_PushRegistersAndAdjustStack(CallerSavedPushRegs, 8);
                         if (consoleType == 0)
                         {
-                            switch ((8 << size) |  num)
+                            switch ((8 << size) | num)
                             {
                             case 32: ABI_CallFunction(SlowRead9<u32, 0>); break;
                             case 33: ABI_CallFunction(SlowRead7<u32, 0>); break;
@@ -392,7 +392,7 @@ Compiler::Compiler()
                         }
                         else
                         {
-                            switch ((8 << size) |  num)
+                            switch ((8 << size) | num)
                             {
                             case 32: ABI_CallFunction(SlowRead9<u32, 1>); break;
                             case 33: ABI_CallFunction(SlowRead7<u32, 1>); break;
@@ -617,9 +617,9 @@ void Compiler::Reset()
     LoadStorePatches.clear();
 }
 
-bool Compiler::IsJITFault(u64 addr)
+bool Compiler::IsJITFault(u8* addr)
 {
-    return addr >= (u64)CodeMemory && addr < (u64)CodeMemory + sizeof(CodeMemory);
+    return (u64)addr >= (u64)ResetStart && (u64)addr < (u64)ResetStart + CodeMemSize;
 }
 
 void Compiler::Comp_SpecialBranchBehaviour(bool taken)
diff --git a/src/ARMJIT_x64/ARMJIT_Compiler.h b/src/ARMJIT_x64/ARMJIT_Compiler.h
index 3e900c3..57aab7b 100644
--- a/src/ARMJIT_x64/ARMJIT_Compiler.h
+++ b/src/ARMJIT_x64/ARMJIT_Compiler.h
@@ -208,9 +208,9 @@ public:
         SetCodePtr(FarCode);
     }
 
-    bool IsJITFault(u64 addr);
+    bool IsJITFault(u8* addr);
 
-    s32 RewriteMemAccess(u64 pc);
+    u8* RewriteMemAccess(u8* pc);
 
     u8* FarCode;
     u8* NearCode;
diff --git a/src/ARMJIT_x64/ARMJIT_LoadStore.cpp b/src/ARMJIT_x64/ARMJIT_LoadStore.cpp
index 8b4e8fe..d80b25b 100644
--- a/src/ARMJIT_x64/ARMJIT_LoadStore.cpp
+++ b/src/ARMJIT_x64/ARMJIT_LoadStore.cpp
@@ -15,28 +15,24 @@ int squeezePointer(T* ptr)
     return truncated;
 }
 
-s32 Compiler::RewriteMemAccess(u64 pc)
+u8* Compiler::RewriteMemAccess(u8* pc)
 {
-    auto it = LoadStorePatches.find((u8*)pc);
+    auto it = LoadStorePatches.find(pc);
     if (it != LoadStorePatches.end())
     {
         LoadStorePatch patch = it->second;
         LoadStorePatches.erase(it);
 
-        u8* curCodePtr = GetWritableCodePtr();
-        u8* rewritePtr = (u8*)pc + (ptrdiff_t)patch.Offset;
-        SetCodePtr(rewritePtr);
+        //printf("rewriting memory access %p %d %d\n", (u8*)pc-ResetStart, patch.Offset, patch.Size);
 
-        CALL(patch.PatchFunc);
-        u32 remainingSize = patch.Size - (GetWritableCodePtr() - rewritePtr);
+        XEmitter emitter(pc + (ptrdiff_t)patch.Offset);
+        emitter.CALL(patch.PatchFunc);
+        ptrdiff_t remainingSize = (ptrdiff_t)patch.Size - 5;
+        assert(remainingSize >= 0);
         if (remainingSize > 0)
-            NOP(remainingSize);
+            emitter.NOP(remainingSize);
 
-        //printf("rewriting memory access %p %d %d\n", patch.PatchFunc, patch.Offset, patch.Size);
-
-        SetCodePtr(curCodePtr);
-
-        return patch.Offset;
+        return pc + (ptrdiff_t)patch.Offset;
     }
 
     printf("this is a JIT bug %llx\n", pc);
@@ -192,6 +188,7 @@ void Compiler::Comp_MemAccess(int rd, int rn, const Op2& op2, int size, int flag
         u8* memopStart = GetWritableCodePtr();
         LoadStorePatch patch;
 
+        assert(rdMapped.GetSimpleReg() >= 0 && rdMapped.GetSimpleReg() < 16);
         patch.PatchFunc = flags & memop_Store
             ? PatchedStoreFuncs[NDS::ConsoleType][Num][__builtin_ctz(size) - 3][rdMapped.GetSimpleReg()]
             : PatchedLoadFuncs[NDS::ConsoleType][Num][__builtin_ctz(size) - 3][!!(flags & memop_SignExtend)][rdMapped.GetSimpleReg()];