General thunking class to allow C-style callbacks to C++ class members - including optional parameters.
CThunk.h
- Committer:
- meriac
- Date:
- 2014-08-21
- Revision:
- 9:d3b51b06ac54
- Parent:
- 8:12fc2cda71af
File content as of revision 9:d3b51b06ac54:
/* General C++ Object Thunking class * * - allows direct callbacks to non-static C++ class functions * - keeps track for the corresponding class instance * - supports an optional context parameter for the called function * - ideally suited for class object receiving interrupts (NVIC_SetVector) * * Copyright (c) 2014 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef __CTHUNK_H__ #define __CTHUNK_H__ #if defined(__CORTEX_M3) || defined(__thumb2__) # define CTHUNK_OPCODE 0x8007E89F; # define CTHUNK_ADDRESS 1 #else # error "TODO: add support for non-cortex-m3 trampoline, too" #endif /* IRQ/Exception compatible thunk entry function */ typedef void (*CThunkEntry)(void); template<class T> class CThunk { public: typedef void (T::*CCallbackSimple)(void); typedef void (T::*CCallback)(void* context); inline CThunk(T *instance) { init(instance, NULL, NULL); } inline CThunk(T *instance, CCallback callback) { init(instance, callback, NULL); } inline CThunk(T *instance, CCallbackSimple callback) { init(instance, (CCallback)callback, NULL); } inline CThunk(T &instance, CCallback callback) { init(instance, callback, NULL); } inline CThunk(T &instance, CCallbackSimple callback) { init(instance, (CCallback)callback, NULL); } inline CThunk(T &instance, CCallback callback, void* context) { init(instance, callback, context); } inline void callback(CCallback callback) { m_callback = callback; } inline void callback(CCallbackSimple callback) { m_callback = (CCallback)callback; } inline void context(void* context) { m_thunk.context = (uint32_t)context; } inline void context(uint32_t context) { m_thunk.context = context; } inline uint32_t entry(void) { return (((uint32_t)&m_thunk)|CTHUNK_ADDRESS); } /* get thunk entry point for connecting rhunk to an IRQ table */ inline operator CThunkEntry(void) { return (CThunkEntry)entry(); } /* get thunk entry point for connecting rhunk to an IRQ table */ inline operator uint32_t(void) { return entry(); } /* simple test function */ inline void call(void) { ((CThunkEntry)(entry())(); } private: T* m_instance; volatile CCallback m_callback; typedef struct { volatile uint32_t code; volatile uint32_t instance; volatile uint32_t context; volatile uint32_t callback; volatile uint32_t trampoline; } __attribute__((packed)) CThunkTrampoline; static void trampoline(T* instance, void* context, CCallback* callback) { if(instance && *callback) (static_cast<T*>(instance)->**callback)(context); } volatile CThunkTrampoline m_thunk; inline void init(T *instance, CCallback callback, void* context) { /* remember callback - need to add this level of redirection as pointer size for member functions differs between platforms */ m_callback = callback; /* populate thunking trampoline */ m_thunk.code = CTHUNK_OPCODE; m_thunk.context = (uint32_t)context; m_thunk.instance = (uint32_t)instance; m_thunk.callback = (uint32_t)&m_callback; m_thunk.trampoline = (uint32_t)&trampoline; __ISB(); __DSB(); } }; #endif/*__CTHUNK_H__*/