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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012 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 <http://www.gnu.org/licenses/>.
*/
/**
* @file crt0_v6m.s
* @brief Generic ARMv6-M (Cortex-M0/M1) startup file for ChibiOS.
*
* @addtogroup ARMCMx_GCC_STARTUP
* @{
*/
/*===========================================================================*/
/* Module constants. */
/*===========================================================================*/
#if !defined(FALSE) || defined(__DOXYGEN__)
#define FALSE 0
#endif
#if !defined(TRUE) || defined(__DOXYGEN__)
#define TRUE 1
#endif
#define CONTROL_MODE_PRIVILEGED 0
#define CONTROL_MODE_UNPRIVILEGED 1
#define CONTROL_USE_MSP 0
#define CONTROL_USE_PSP 2
/*===========================================================================*/
/* Module pre-compile time 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 (CONTROL_USE_PSP | \
CONTROL_MODE_PRIVILEGED)
#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
/*===========================================================================*/
/* Code section. */
/*===========================================================================*/
#if !defined(__DOXYGEN__)
.cpu cortex-m0
.fpu softvfp
.thumb
.text
/*
* Reset handler.
*/
.thumb_func
.global Reset_Handler
.weak Reset_Handler
Reset_Handler:
/* Interrupts are globally masked initially.*/
cpsid i
/* PSP stack pointers initialization.*/
ldr r0, =__process_stack_end__
msr PSP, r0
/* CPU mode initialization as configured.*/
movs r0, #CRT0_CONTROL_INIT
msr CONTROL, r0
isb
/* Early initialization..*/
bl __early_init
#if CRT0_INIT_STACKS == TRUE
ldr r0, =CRT0_STACKS_FILL_PATTERN
/* Main Stack initialization. Note, it assumes that the
stack size is a multiple of 4 so the linker file must
ensure this.*/
ldr r1, =__main_stack_base__
ldr r2, =__main_stack_end__
msloop:
cmp r1, r2
bge endmsloop
str r0, [r1]
add r1, r1, #4
b msloop
endmsloop:
/* Process Stack initialization. Note, it assumes that the
stack size is a multiple of 4 so the linker file must
ensure this.*/
ldr r1, =__process_stack_base__
ldr r2, =__process_stack_end__
psloop:
cmp r1, r2
bge endpsloop
str r0, [r1]
add r1, r1, #4
b psloop
endpsloop:
#endif
#if CRT0_INIT_DATA == TRUE
/* Data initialization. Note, it assumes that the DATA size
is a multiple of 4 so the linker file must ensure this.*/
ldr r1, =_textdata
ldr r2, =_data
ldr r3, =_edata
dloop:
cmp r2, r3
bge enddloop
ldr r0, [r1]
str r0, [r2]
add r1, r1, #4
add r2, r2, #4
b dloop
enddloop:
#endif
#if CRT0_INIT_BSS == TRUE
/* BSS initialization. Note, it assumes that the DATA size
is a multiple of 4 so the linker file must ensure this.*/
movs r0, #0
ldr r1, =_bss_start
ldr r2, =_bss_end
bloop:
cmp r1, r2
bge endbloop
str r0, [r1]
add r1, r1, #4
b bloop
endbloop:
#endif
/* Late initialization..*/
bl __late_init
#if CRT0_CALL_CONSTRUCTORS == TRUE
/* Constructors invocation.*/
ldr r4, =__init_array_start
ldr r5, =__init_array_end
initloop:
cmp r4, r5
bge endinitloop
ldr r1, [r4]
blx r1
add r4, r4, #4
b initloop
endinitloop:
#endif
/* Main program invocation, r0 contains the returned value.*/
bl main
#if CRT0_CALL_CONSTRUCTORS == TRUE
/* Destructors invocation.*/
ldr r4, =__fini_array_start
ldr r5, =__fini_array_end
finiloop:
cmp r4, r5
bge endfiniloop
ldr r1, [r4]
blx r1
add r4, r4, #4
b finiloop
endfiniloop:
#endif
/* Branching to the defined exit handler.*/
b __default_exit
/*--------------------------------------------------------------------------*
* Default main exit code, the system is halted.
* It is a weak symbol, the application code can redefine the behavior.
* R0 contains the value returned by the main function.
*--------------------------------------------------------------------------*/
.thumb_func
.weak __default_exit
__default_exit:
cpsid i
.loop: b .loop
/*--------------------------------------------------------------------------*
* Default early initialization code. It is declared weak in order to be
* replaced by the real initialization code.
* The early initialization is performed just after stacks setup RAM areas
* initialization.
*--------------------------------------------------------------------------*/
.thumb_func
.weak __early_init
__early_init:
bx lr
/*--------------------------------------------------------------------------*
* Default late initialization code. It is declared weak in order to be
* replaced by the real initialization code.
* The late initialization is performed just after RAM areas initialization
* and before invoking the static constructors.
*--------------------------------------------------------------------------*/
.thumb_func
.weak __late_init
__late_init:
bx lr
#endif
/** @} */
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