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stm32bringup/cstartup.c

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/* cstartup.c -- data and bss RAM memory initialization
** Copyright (c) 2020 Renaud Fivet
*/
/* Memory locations defined by linker script */
extern long __StackTop ; /* &__StackTop points after end of stack */
void Reset_Handler( void) ; /* Entry point for execution */
extern const long __etext[] ; /* start of initialized data copy in flash */
extern long __data_start__[] ;
extern long __bss_start__[] ;
extern long __bss_end__ ; /* &__bss_end__ points after end of bss */
/* Interrupt vector table:
* 1 Stack Pointer reset value
* 15 System Exceptions
* NN Device specific Interrupts
*/
typedef void (*isr_p)( void) ;
isr_p const isr_vector[ 2] __attribute__((section(".isr_vector"))) = {
(isr_p) &__StackTop,
/* System Exceptions */
Reset_Handler
} ;
extern int main( void) ;
void Reset_Handler( void) {
const long *f ; /* from, source constant data from FLASH */
long *t ; /* to, destination in RAM */
/* Assume:
** __bss_start__ == __data_end__
** All sections are 4 bytes aligned
*/
f = __etext ;
for( t = __data_start__ ; t < __bss_start__ ; t += 1)
*t = *f++ ;
while( t < &__bss_end__)
*t++ = 0 ;
main() ;
for( ;;) ;
}
/** Test code: main.c *********************************************************/
const char hexa[] = "0123456789abcdef" ;
long first = 1 ;
long i ;
int main( void) {
static char c = 'a' ;
char *cp = &c ;
*cp += i ;
i += hexa[ 13] - c + first++ ;
return 0 ;
}
/* end of cstartup.c */