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/*
ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
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.
*/
/**
* @file crt0_v6m.S
* @brief Generic ARMv6-M (Cortex-M0/M1) startup file for ChibiOS.
*
* @addtogroup ARMCMx_GCC_STARTUP_V6M
* @{
*/
/*===========================================================================*/
/* 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
#define SCB_VTOR 0xE000ED08
/*===========================================================================*/
/* Module pre-compile time settings. */
/*===========================================================================*/
/**
* @brief Enforces initialization of MSP.
* @note This is required if the boot process is not reliable for whatever
* reason (bad ROMs, bad bootloaders, bad debuggers=.
*/
#if !defined(CRT0_FORCE_MSP_INIT) || defined(__DOXYGEN__)
#define CRT0_FORCE_MSP_INIT TRUE
#endif
/**
* @brief VTOR special register initialization.
* @details VTOR is initialized to point to the vectors table.
* @note This option can only be enabled on Cortex-M0+ cores.
*/
#if !defined(CRT0_VTOR_INIT) || defined(__DOXYGEN__)
#define CRT0_VTOR_INIT FALSE
#endif
/**
* @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 Core initialization switch.
*/
#if !defined(CRT0_INIT_CORE) || defined(__DOXYGEN__)
#define CRT0_INIT_CORE TRUE
#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 RAM areas initialization switch.
*/
#if !defined(CRT0_INIT_RAM_AREAS) || defined(__DOXYGEN__)
#define CRT0_INIT_RAM_AREAS 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
.syntax unified
.thumb
.text
/*
* CRT0 entry point.
*/
.align 2
.thumb_func
.global _crt0_entry
_crt0_entry:
/* Interrupts are globally masked initially.*/
cpsid i
#if CRT0_FORCE_MSP_INIT == TRUE
/* MSP stack pointers initialization.*/
ldr r0, =__main_stack_end__
msr MSP, r0
#endif
/* 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
#if CRT0_VTOR_INIT == TRUE
ldr r0, =_vectors
ldr r1, =SCB_VTOR
str r0, [r1]
#endif
#if CRT0_INIT_CORE == TRUE
/* Core initialization.*/
bl __core_init
#endif
/* 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]
adds 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]
adds 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]
adds r1, #4
adds 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]
adds r1, #4
b bloop
endbloop:
#endif
#if CRT0_INIT_RAM_AREAS == TRUE
/* RAM areas initialization.*/
bl __init_ram_areas
#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
adds r4, #4
b initloop
endinitloop:
#endif
/* Main program invocation, r0 contains the returned value.*/
bl main
#if CRT0_CALL_DESTRUCTORS == TRUE
/* Destructors invocation.*/
ldr r4, =__fini_array_start
ldr r5, =__fini_array_end
finiloop:
cmp r4, r5
bge endfiniloop
ldr r1, [r4]
blx r1
adds r4, #4
b finiloop
endfiniloop:
#endif
/* Branching to the defined exit handler.*/
ldr r1, =__default_exit
bx r1
#endif
/** @} */
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