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Diffstat (limited to 'ext/CThunk.h')
| -rw-r--r-- | ext/CThunk.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/ext/CThunk.h b/ext/CThunk.h new file mode 100644 index 0000000..96f3331 --- /dev/null +++ b/ext/CThunk.h @@ -0,0 +1,202 @@ +/* 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__*/ |