Giovanni Bauermeister / mbed-dev-bin

example micro:bit pedometer

Fork of mbed-dev-bin by Lancaster University

CThunk.h@4:084689a02e93, 2018-04-27 (annotated)

Committer:
giobauermeister
Date:
Fri Apr 27 12:59:57 2018 +0000
Revision:
4:084689a02e93
Parent:
0:e1a608bb55e8 
example micro:bit pedometer

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jamesadevine 0:e1a608bb55e8 1 /* General C++ Object Thunking class
jamesadevine 0:e1a608bb55e8 2 *
jamesadevine 0:e1a608bb55e8 3 * - allows direct callbacks to non-static C++ class functions
jamesadevine 0:e1a608bb55e8 4 * - keeps track for the corresponding class instance
jamesadevine 0:e1a608bb55e8 5 * - supports an optional context parameter for the called function
jamesadevine 0:e1a608bb55e8 6 * - ideally suited for class object receiving interrupts (NVIC_SetVector)
jamesadevine 0:e1a608bb55e8 7 *
jamesadevine 0:e1a608bb55e8 8 * Copyright (c) 2014-2015 ARM Limited
jamesadevine 0:e1a608bb55e8 9 *
jamesadevine 0:e1a608bb55e8 10 * Licensed under the Apache License, Version 2.0 (the "License");
jamesadevine 0:e1a608bb55e8 11 * you may not use this file except in compliance with the License.
jamesadevine 0:e1a608bb55e8 12 * You may obtain a copy of the License at
jamesadevine 0:e1a608bb55e8 13 *
jamesadevine 0:e1a608bb55e8 14 * http://www.apache.org/licenses/LICENSE-2.0
jamesadevine 0:e1a608bb55e8 15 *
jamesadevine 0:e1a608bb55e8 16 * Unless required by applicable law or agreed to in writing, software
jamesadevine 0:e1a608bb55e8 17 * distributed under the License is distributed on an "AS IS" BASIS,
jamesadevine 0:e1a608bb55e8 18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
jamesadevine 0:e1a608bb55e8 19 * See the License for the specific language governing permissions and
jamesadevine 0:e1a608bb55e8 20 * limitations under the License.
jamesadevine 0:e1a608bb55e8 21 */
jamesadevine 0:e1a608bb55e8 22 #ifndef __CTHUNK_H__
jamesadevine 0:e1a608bb55e8 23 #define __CTHUNK_H__
jamesadevine 0:e1a608bb55e8 24
jamesadevine 0:e1a608bb55e8 25 #define CTHUNK_ADDRESS 1
jamesadevine 0:e1a608bb55e8 26
jamesadevine 0:e1a608bb55e8 27 #if defined(__CORTEX_M3) || defined(__CORTEX_M4) || defined(__thumb2__)
jamesadevine 0:e1a608bb55e8 28 #define CTHUNK_VARIABLES volatile uint32_t code[1]
jamesadevine 0:e1a608bb55e8 29 /**
jamesadevine 0:e1a608bb55e8 30 * CTHUNK disassembly for Cortex-M3/M4 (thumb2):
jamesadevine 0:e1a608bb55e8 31 * * ldm.w pc,{r0,r1,r2,pc}
jamesadevine 0:e1a608bb55e8 32 *
jamesadevine 0:e1a608bb55e8 33 * This instruction loads the arguments for the static thunking function to r0-r2, and
jamesadevine 0:e1a608bb55e8 34 * branches to that function by loading its address into PC.
jamesadevine 0:e1a608bb55e8 35 *
jamesadevine 0:e1a608bb55e8 36 * This is safe for both regular calling and interrupt calling, since it only touches scratch registers
jamesadevine 0:e1a608bb55e8 37 * which should be saved by the caller, and are automatically saved as part of the IRQ context switch.
jamesadevine 0:e1a608bb55e8 38 */
jamesadevine 0:e1a608bb55e8 39 #define CTHUNK_ASSIGMENT m_thunk.code[0] = 0x8007E89F
jamesadevine 0:e1a608bb55e8 40
jamesadevine 0:e1a608bb55e8 41 #elif defined(__CORTEX_M0PLUS) || defined(__CORTEX_M0)
jamesadevine 0:e1a608bb55e8 42 /*
jamesadevine 0:e1a608bb55e8 43 * CTHUNK disassembly for Cortex M0 (thumb):
jamesadevine 0:e1a608bb55e8 44 * * push {r0,r1,r2,r3,r4,lr} save touched registers and return address
jamesadevine 0:e1a608bb55e8 45 * * movs r4,#4 set up address to load arguments from (immediately following this code block) (1)
jamesadevine 0:e1a608bb55e8 46 * * add r4,pc set up address to load arguments from (immediately following this code block) (2)
jamesadevine 0:e1a608bb55e8 47 * * ldm r4!,{r0,r1,r2,r3} load arguments for static thunk function
jamesadevine 0:e1a608bb55e8 48 * * blx r3 call static thunk function
jamesadevine 0:e1a608bb55e8 49 * * pop {r0,r1,r2,r3,r4,pc} restore scratch registers and return from function
jamesadevine 0:e1a608bb55e8 50 */
jamesadevine 0:e1a608bb55e8 51 #define CTHUNK_VARIABLES volatile uint32_t code[3]
jamesadevine 0:e1a608bb55e8 52 #define CTHUNK_ASSIGMENT do { \
jamesadevine 0:e1a608bb55e8 53 m_thunk.code[0] = 0x2404B51F; \
jamesadevine 0:e1a608bb55e8 54 m_thunk.code[1] = 0xCC0F447C; \
jamesadevine 0:e1a608bb55e8 55 m_thunk.code[2] = 0xBD1F4798; \
jamesadevine 0:e1a608bb55e8 56 } while (0)
jamesadevine 0:e1a608bb55e8 57
jamesadevine 0:e1a608bb55e8 58 #else
jamesadevine 0:e1a608bb55e8 59 #error "Target is not currently suported."
jamesadevine 0:e1a608bb55e8 60 #endif
jamesadevine 0:e1a608bb55e8 61
jamesadevine 0:e1a608bb55e8 62 /* IRQ/Exception compatible thunk entry function */
jamesadevine 0:e1a608bb55e8 63 typedef void (*CThunkEntry)(void);
jamesadevine 0:e1a608bb55e8 64
jamesadevine 0:e1a608bb55e8 65 template<class T>
jamesadevine 0:e1a608bb55e8 66 class CThunk
jamesadevine 0:e1a608bb55e8 67 {
jamesadevine 0:e1a608bb55e8 68 public:
jamesadevine 0:e1a608bb55e8 69 typedef void (T::*CCallbackSimple)(void);
jamesadevine 0:e1a608bb55e8 70 typedef void (T::*CCallback)(void* context);
jamesadevine 0:e1a608bb55e8 71
jamesadevine 0:e1a608bb55e8 72 inline CThunk(T *instance)
jamesadevine 0:e1a608bb55e8 73 {
jamesadevine 0:e1a608bb55e8 74 init(instance, NULL, NULL);
jamesadevine 0:e1a608bb55e8 75 }
jamesadevine 0:e1a608bb55e8 76
jamesadevine 0:e1a608bb55e8 77 inline CThunk(T *instance, CCallback callback)
jamesadevine 0:e1a608bb55e8 78 {
jamesadevine 0:e1a608bb55e8 79 init(instance, callback, NULL);
jamesadevine 0:e1a608bb55e8 80 }
jamesadevine 0:e1a608bb55e8 81
jamesadevine 0:e1a608bb55e8 82 ~CThunk() {
jamesadevine 0:e1a608bb55e8 83
jamesadevine 0:e1a608bb55e8 84 }
jamesadevine 0:e1a608bb55e8 85
jamesadevine 0:e1a608bb55e8 86 inline CThunk(T *instance, CCallbackSimple callback)
jamesadevine 0:e1a608bb55e8 87 {
jamesadevine 0:e1a608bb55e8 88 init(instance, (CCallback)callback, NULL);
jamesadevine 0:e1a608bb55e8 89 }
jamesadevine 0:e1a608bb55e8 90
jamesadevine 0:e1a608bb55e8 91 inline CThunk(T &instance, CCallback callback)
jamesadevine 0:e1a608bb55e8 92 {
jamesadevine 0:e1a608bb55e8 93 init(instance, callback, NULL);
jamesadevine 0:e1a608bb55e8 94 }
jamesadevine 0:e1a608bb55e8 95
jamesadevine 0:e1a608bb55e8 96 inline CThunk(T &instance, CCallbackSimple callback)
jamesadevine 0:e1a608bb55e8 97 {
jamesadevine 0:e1a608bb55e8 98 init(instance, (CCallback)callback, NULL);
jamesadevine 0:e1a608bb55e8 99 }
jamesadevine 0:e1a608bb55e8 100
jamesadevine 0:e1a608bb55e8 101 inline CThunk(T &instance, CCallback callback, void* context)
jamesadevine 0:e1a608bb55e8 102 {
jamesadevine 0:e1a608bb55e8 103 init(instance, callback, context);
jamesadevine 0:e1a608bb55e8 104 }
jamesadevine 0:e1a608bb55e8 105
jamesadevine 0:e1a608bb55e8 106 inline void callback(CCallback callback)
jamesadevine 0:e1a608bb55e8 107 {
jamesadevine 0:e1a608bb55e8 108 m_callback = callback;
jamesadevine 0:e1a608bb55e8 109 }
jamesadevine 0:e1a608bb55e8 110
jamesadevine 0:e1a608bb55e8 111 inline void callback(CCallbackSimple callback)
jamesadevine 0:e1a608bb55e8 112 {
jamesadevine 0:e1a608bb55e8 113 m_callback = (CCallback)callback;
jamesadevine 0:e1a608bb55e8 114 }
jamesadevine 0:e1a608bb55e8 115
jamesadevine 0:e1a608bb55e8 116 inline void context(void* context)
jamesadevine 0:e1a608bb55e8 117 {
jamesadevine 0:e1a608bb55e8 118 m_thunk.context = (uint32_t)context;
jamesadevine 0:e1a608bb55e8 119 }
jamesadevine 0:e1a608bb55e8 120
jamesadevine 0:e1a608bb55e8 121 inline void context(uint32_t context)
jamesadevine 0:e1a608bb55e8 122 {
jamesadevine 0:e1a608bb55e8 123 m_thunk.context = context;
jamesadevine 0:e1a608bb55e8 124 }
jamesadevine 0:e1a608bb55e8 125
jamesadevine 0:e1a608bb55e8 126 inline uint32_t entry(void)
jamesadevine 0:e1a608bb55e8 127 {
jamesadevine 0:e1a608bb55e8 128 return (((uint32_t)&m_thunk)|CTHUNK_ADDRESS);
jamesadevine 0:e1a608bb55e8 129 }
jamesadevine 0:e1a608bb55e8 130
jamesadevine 0:e1a608bb55e8 131 /* get thunk entry point for connecting rhunk to an IRQ table */
jamesadevine 0:e1a608bb55e8 132 inline operator CThunkEntry(void)
jamesadevine 0:e1a608bb55e8 133 {
jamesadevine 0:e1a608bb55e8 134 return (CThunkEntry)entry();
jamesadevine 0:e1a608bb55e8 135 }
jamesadevine 0:e1a608bb55e8 136
jamesadevine 0:e1a608bb55e8 137 /* get thunk entry point for connecting rhunk to an IRQ table */
jamesadevine 0:e1a608bb55e8 138 inline operator uint32_t(void)
jamesadevine 0:e1a608bb55e8 139 {
jamesadevine 0:e1a608bb55e8 140 return entry();
jamesadevine 0:e1a608bb55e8 141 }
jamesadevine 0:e1a608bb55e8 142
jamesadevine 0:e1a608bb55e8 143 /* simple test function */
jamesadevine 0:e1a608bb55e8 144 inline void call(void)
jamesadevine 0:e1a608bb55e8 145 {
jamesadevine 0:e1a608bb55e8 146 (((CThunkEntry)(entry()))());
jamesadevine 0:e1a608bb55e8 147 }
jamesadevine 0:e1a608bb55e8 148
jamesadevine 0:e1a608bb55e8 149 private:
jamesadevine 0:e1a608bb55e8 150 T* m_instance;
jamesadevine 0:e1a608bb55e8 151 volatile CCallback m_callback;
jamesadevine 0:e1a608bb55e8 152
jamesadevine 0:e1a608bb55e8 153 // TODO: this needs proper fix, to refactor toolchain header file and all its use
jamesadevine 0:e1a608bb55e8 154 // PACKED there is not defined properly for IAR
jamesadevine 0:e1a608bb55e8 155 #if defined (__ICCARM__)
jamesadevine 0:e1a608bb55e8 156 typedef __packed struct
jamesadevine 0:e1a608bb55e8 157 {
jamesadevine 0:e1a608bb55e8 158 CTHUNK_VARIABLES;
jamesadevine 0:e1a608bb55e8 159 volatile uint32_t instance;
jamesadevine 0:e1a608bb55e8 160 volatile uint32_t context;
jamesadevine 0:e1a608bb55e8 161 volatile uint32_t callback;
jamesadevine 0:e1a608bb55e8 162 volatile uint32_t trampoline;
jamesadevine 0:e1a608bb55e8 163 } CThunkTrampoline;
jamesadevine 0:e1a608bb55e8 164 #else
jamesadevine 0:e1a608bb55e8 165 typedef struct
jamesadevine 0:e1a608bb55e8 166 {
jamesadevine 0:e1a608bb55e8 167 CTHUNK_VARIABLES;
jamesadevine 0:e1a608bb55e8 168 volatile uint32_t instance;
jamesadevine 0:e1a608bb55e8 169 volatile uint32_t context;
jamesadevine 0:e1a608bb55e8 170 volatile uint32_t callback;
jamesadevine 0:e1a608bb55e8 171 volatile uint32_t trampoline;
jamesadevine 0:e1a608bb55e8 172 } __attribute__((__packed__)) CThunkTrampoline;
jamesadevine 0:e1a608bb55e8 173 #endif
jamesadevine 0:e1a608bb55e8 174
jamesadevine 0:e1a608bb55e8 175 static void trampoline(T* instance, void* context, CCallback* callback)
jamesadevine 0:e1a608bb55e8 176 {
jamesadevine 0:e1a608bb55e8 177 if(instance && *callback) {
jamesadevine 0:e1a608bb55e8 178 (static_cast<T*>(instance)->**callback)(context);
jamesadevine 0:e1a608bb55e8 179 }
jamesadevine 0:e1a608bb55e8 180 }
jamesadevine 0:e1a608bb55e8 181
jamesadevine 0:e1a608bb55e8 182 volatile CThunkTrampoline m_thunk;
jamesadevine 0:e1a608bb55e8 183
jamesadevine 0:e1a608bb55e8 184 inline void init(T *instance, CCallback callback, void* context)
jamesadevine 0:e1a608bb55e8 185 {
jamesadevine 0:e1a608bb55e8 186 /* remember callback - need to add this level of redirection
jamesadevine 0:e1a608bb55e8 187 as pointer size for member functions differs between platforms */
jamesadevine 0:e1a608bb55e8 188 m_callback = callback;
jamesadevine 0:e1a608bb55e8 189
jamesadevine 0:e1a608bb55e8 190 /* populate thunking trampoline */
jamesadevine 0:e1a608bb55e8 191 CTHUNK_ASSIGMENT;
jamesadevine 0:e1a608bb55e8 192 m_thunk.context = (uint32_t)context;
jamesadevine 0:e1a608bb55e8 193 m_thunk.instance = (uint32_t)instance;
jamesadevine 0:e1a608bb55e8 194 m_thunk.callback = (uint32_t)&m_callback;
jamesadevine 0:e1a608bb55e8 195 m_thunk.trampoline = (uint32_t)&trampoline;
jamesadevine 0:e1a608bb55e8 196
jamesadevine 0:e1a608bb55e8 197 __ISB();
jamesadevine 0:e1a608bb55e8 198 __DSB();
jamesadevine 0:e1a608bb55e8 199 }
jamesadevine 0:e1a608bb55e8 200 };
jamesadevine 0:e1a608bb55e8 201
jamesadevine 0:e1a608bb55e8 202 #endif/*__CTHUNK_H__*/