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CThunk.h
- Committer:
- jhon309
- Date:
- 2015-08-20
- Revision:
- 0:666850d06c9f
File content as of revision 0:666850d06c9f:
/* 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) 2014-2015 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__ #define CTHUNK_ADDRESS 1 #if defined(__CORTEX_M3) || defined(__CORTEX_M4) || defined(__thumb2__) #define CTHUNK_VARIABLES volatile uint32_t code[1] /** * CTHUNK disassembly for Cortex-M3/M4 (thumb2): * * ldm.w pc,{r0,r1,r2,pc} * * This instruction loads the arguments for the static thunking function to r0-r2, and * branches to that function by loading its address into PC. * * This is safe for both regular calling and interrupt calling, since it only touches scratch registers * which should be saved by the caller, and are automatically saved as part of the IRQ context switch. */ #define CTHUNK_ASSIGMENT m_thunk.code[0] = 0x8007E89F #elif defined(__CORTEX_M0PLUS) || defined(__CORTEX_M0) /* * CTHUNK disassembly for Cortex M0 (thumb): * * push {r0,r1,r2,r3,r4,lr} save touched registers and return address * * movs r4,#4 set up address to load arguments from (immediately following this code block) (1) * * add r4,pc set up address to load arguments from (immediately following this code block) (2) * * ldm r4!,{r0,r1,r2,r3} load arguments for static thunk function * * blx r3 call static thunk function * * pop {r0,r1,r2,r3,r4,pc} restore scratch registers and return from function */ #define CTHUNK_VARIABLES volatile uint32_t code[3] #define CTHUNK_ASSIGMENT do { \ m_thunk.code[0] = 0x2404B51F; \ m_thunk.code[1] = 0xCC0F447C; \ m_thunk.code[2] = 0xBD1F4798; \ } while (0) #else #error "Target is not currently suported." #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); } ~CThunk() { } 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; // TODO: this needs proper fix, to refactor toolchain header file and all its use // PACKED there is not defined properly for IAR #if defined (__ICCARM__) typedef __packed struct { CTHUNK_VARIABLES; volatile uint32_t instance; volatile uint32_t context; volatile uint32_t callback; volatile uint32_t trampoline; } CThunkTrampoline; #else typedef struct { CTHUNK_VARIABLES; volatile uint32_t instance; volatile uint32_t context; volatile uint32_t callback; volatile uint32_t trampoline; } __attribute__((__packed__)) CThunkTrampoline; #endif 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 */ CTHUNK_ASSIGMENT; 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__*/