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// very simple startup code with definition of handlers for all cortex-m cores
typedef void (*ptr_func_t)();
// main application
extern "C" int main();
// location of these variables is defined in linker script
extern unsigned __data_start;
extern unsigned __data_end;
extern unsigned __data_load;
extern unsigned __bss_start;
extern unsigned __bss_end;
extern unsigned __heap_start;
extern ptr_func_t __preinit_array_start[];
extern ptr_func_t __preinit_array_end[];
extern ptr_func_t __init_array_start[];
extern ptr_func_t __init_array_end[];
extern ptr_func_t __fini_array_start[];
extern ptr_func_t __fini_array_end[];
/** Copy default data to DATA section
*/
void copy_data() {
unsigned *src = &__data_load;
unsigned *dst = &__data_start;
while (dst < &__data_end) {
*dst++ = *src++;
}
}
/** Erase BSS section
*/
void zero_bss() {
unsigned *dst = &__bss_start;
while (dst < &__bss_end) {
*dst++ = 0;
}
}
/** Fill heap memory
*/
void fill_heap(unsigned fill=0x45455246) {
unsigned *dst = &__heap_start;
unsigned *msp_reg;
__asm__("mrs %0, msp\n" : "=r" (msp_reg) );
while (dst < msp_reg) {
*dst++ = fill;
}
}
/** Call constructors for static objects
*/
void call_init_array() {
auto array = __preinit_array_start;
while (array < __preinit_array_end) {
(*array)();
array++;
}
array = __init_array_start;
while (array < __init_array_end) {
(*array)();
array++;
}
}
/** Call destructors for static objects
*/
void call_fini_array() {
auto array = __fini_array_start;
while (array < __fini_array_end) {
(*array)();
array++;
}
}
// reset handler
extern "C" void RESET_handler() {
copy_data();
zero_bss();
fill_heap();
call_init_array();
// run application
main();
// call destructors for static instances
call_fini_array();
// stop
while (true);
}
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