/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012,2013 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @file ARMCMx/crt0.c
* @brief Generic ARMvx-M (Cortex-M0/M1/M3/M4) startup file for ChibiOS/RT.
*
* @addtogroup ARMCMx_STARTUP
* @{
*/
#include
#if !defined(FALSE)
#define FALSE 0
#endif
#if !defined(TRUE)
#define TRUE (!FALSE)
#endif
#define SCB_CPACR *((uint32_t *)0xE000ED88U)
#define SCB_FPCCR *((uint32_t *)0xE000EF34U)
#define SCB_FPDSCR *((uint32_t *)0xE000EF3CU)
#define FPCCR_ASPEN (0x1U << 31)
#define FPCCR_LSPEN (0x1U << 30)
typedef void (*funcp_t)(void);
typedef funcp_t * funcpp_t;
#define SYMVAL(sym) (uint32_t)(((uint8_t *)&(sym)) - ((uint8_t *)0))
/*
* Area fill code, it is a macro because here functions cannot be called
* until stacks are initialized.
*/
#define fill32(start, end, filler) { \
uint32_t *p1 = start; \
uint32_t *p2 = end; \
while (p1 < p2) \
*p1++ = filler; \
}
/*===========================================================================*/
/**
* @name Startup settings
* @{
*/
/*===========================================================================*/
/**
* @brief Control special register initialization value.
* @details The system is setup to run in privileged mode using the PSP
* stack (dual stack mode).
*/
#if !defined(CRT0_CONTROL_INIT) || defined(__DOXYGEN__)
#define CRT0_CONTROL_INIT 0x00000002
#endif
/**
* @brief Stack segments initialization switch.
*/
#if !defined(CRT0_STACKS_FILL_PATTERN) || defined(__DOXYGEN__)
#define CRT0_STACKS_FILL_PATTERN 0x55555555
#endif
/**
* @brief Stack segments initialization switch.
*/
#if !defined(CRT0_INIT_STACKS) || defined(__DOXYGEN__)
#define CRT0_INIT_STACKS TRUE
#endif
/**
* @brief DATA segment initialization switch.
*/
#if !defined(CRT0_INIT_DATA) || defined(__DOXYGEN__)
#define CRT0_INIT_DATA TRUE
#endif
/**
* @brief BSS segment initialization switch.
*/
#if !defined(CRT0_INIT_BSS) || defined(__DOXYGEN__)
#define CRT0_INIT_BSS TRUE
#endif
/**
* @brief Constructors invocation switch.
*/
#if !defined(CRT0_CALL_CONSTRUCTORS) || defined(__DOXYGEN__)
#define CRT0_CALL_CONSTRUCTORS TRUE
#endif
/**
* @brief Destructors invocation switch.
*/
#if !defined(CRT0_CALL_DESTRUCTORS) || defined(__DOXYGEN__)
#define CRT0_CALL_DESTRUCTORS TRUE
#endif
/** @} */
/*===========================================================================*/
/**
* @name Symbols from the scatter file
*/
/*===========================================================================*/
/**
* @brief Main stack lower boundary.
* @details This symbol must be exported by the linker script and represents
* the main stack lower boundary.
*/
extern uint32_t __main_stack_base__;
/**
*
* @brief Main stack initial position.
* @details This symbol must be exported by the linker script and represents
* the main stack initial position.
*/
extern uint32_t __main_stack_end__;
/**
* @brief Process stack lower boundary.
* @details This symbol must be exported by the linker script and represents
* the process stack lower boundary.
*/
extern uint32_t __process_stack_base__;
/**
* @brief Process stack initial position.
* @details This symbol must be exported by the linker script and represents
* the process stack initial position.
*/
extern uint32_t __process_stack_end__;
/**
* @brief ROM image of the data segment start.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern uint32_t _textdata;
/**
* @brief Data segment start.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern uint32_t _data;
/**
* @brief Data segment end.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern uint32_t _edata;
/**
* @brief BSS segment start.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern uint32_t _bss_start;
/**
* @brief BSS segment end.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern uint32_t _bss_end;
/**
* @brief Constructors table start.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern funcp_t __init_array_start;
/**
* @brief Constructors table end.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern funcp_t __init_array_end;
/**
* @brief Destructors table start.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern funcp_t __fini_array_start;
/**
* @brief Destructors table end.
* @pre The symbol must be aligned to a 32 bits boundary.
*/
extern funcp_t __fini_array_end;
/** @} */
/**
* @brief Application @p main() function.
*/
extern void main(void);
/**
* @brief Early initialization.
* @details This hook is invoked immediately after the stack initialization
* and before the DATA and BSS segments initialization. The
* default behavior is to do nothing.
* @note This function is a weak symbol.
*/
#if !defined(__DOXYGEN__)
__attribute__((weak))
#endif
void __early_init(void) {}
/**
* @brief Late initialization.
* @details This hook is invoked after the DATA and BSS segments
* initialization and before any static constructor. The
* default behavior is to do nothing.
* @note This function is a weak symbol.
*/
#if !defined(__DOXYGEN__)
__attribute__((weak))
#endif
void __late_init(void) {}
/**
* @brief Default @p main() function exit handler.
* @details This handler is invoked or the @p main() function exit. The
* default behavior is to enter an infinite loop.
* @note This function is a weak symbol.
*/
#if !defined(__DOXYGEN__)
__attribute__((weak, naked))
#endif
void _default_exit(void) {
while (1)
;
}
/**
* @brief Reset vector.
*/
#if !defined(__DOXYGEN__)
__attribute__((naked))
#endif
void ResetHandler(void) {
uint32_t psp, reg;
/* Process Stack initialization, it is allocated starting from the
symbol __process_stack_end__ and its lower limit is the symbol
__process_stack_base__.*/
asm volatile ("cpsid i");
psp = SYMVAL(__process_stack_end__);
asm volatile ("msr PSP, %0" : : "r" (psp));
#if CORTEX_USE_FPU
/* Initializing the FPU context save in lazy mode.*/
SCB_FPCCR = FPCCR_ASPEN | FPCCR_LSPEN;
/* CP10 and CP11 set to full access.*/
SCB_CPACR |= 0x00F00000;
/* FPSCR and FPDSCR initially zero.*/
reg = 0;
asm volatile ("vmsr FPSCR, %0" : : "r" (reg) : "memory");
SCB_FPDSCR = reg;
/* CPU mode initialization, enforced FPCA bit.*/
reg = CRT0_CONTROL_INIT | 4;
#else
/* CPU mode initialization.*/
reg = CRT0_CONTROL_INIT;
#endif
asm volatile ("msr CONTROL, %0" : : "r" (reg));
asm volatile ("isb");
#if CRT0_INIT_STACKS
/* Main and Process stacks initialization.*/
fill32(&__main_stack_base__,
&__main_stack_end__,
CRT0_STACKS_FILL_PATTERN);
fill32(&__process_stack_base__,
&__process_stack_end__,
CRT0_STACKS_FILL_PATTERN);
#endif
/* Early initialization hook invocation.*/
__early_init();
#if CRT0_INIT_DATA
/* DATA segment initialization.*/
{
uint32_t *tp, *dp;
tp = &_textdata;
dp = &_data;
while (dp < &_edata)
*dp++ = *tp++;
}
#endif
#if CRT0_INIT_BSS
/* BSS segment initialization.*/
fill32(&_bss_start, &_bss_end, 0);
#endif
/* Late initialization hook invocation.*/
__late_init();
#if CRT0_CALL_CONSTRUCTORS
/* Constructors invocation.*/
{
funcpp_t fpp = &__init_array_start;
while (fpp < &__init_array_end) {
(*fpp)();
fpp++;
}
}
#endif
/* Invoking application main() function.*/
main();
#if CRT0_CALL_DESTRUCTORS
/* Destructors invocation.*/
{
funcpp_t fpp = &__fini_array_start;
while (fpp < &__fini_array_end) {
(*fpp)();
fpp++;
}
}
#endif
/* Invoking the exit handler.*/
_default_exit();
}
/** @} */