62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
/* cstartup.c -- data and bss RAM memory initialization
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** Copyright (c) 2020-2021 Renaud Fivet
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*/
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/* Memory locations defined by linker script */
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void __StackTop( void) ; /* __StackTop points after end of stack */
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void Reset_Handler( void) ; /* Entry point for execution */
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extern const long __etext[] ; /* start of initialized data copy in flash */
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extern long __data_start__[] ;
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extern long __bss_start__[] ;
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extern long __bss_end__ ; /* &__bss_end__ points after end of bss */
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/* Interrupt vector table:
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* 1 Stack Pointer reset value
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* 15 System Exceptions
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* NN Device specific Interrupts
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*/
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typedef void (*isr_p)( void) ;
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isr_p const isr_vector[ 2] __attribute__((section(".isr_vector"))) = {
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__StackTop,
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/* System Exceptions */
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Reset_Handler
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} ;
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int main( void) ;
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void Reset_Handler( void) {
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const long *f ; /* from, source constant data from FLASH */
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long *t ; /* to, destination in RAM */
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/* Assume:
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** __bss_start__ == __data_end__
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** All sections are 4 bytes aligned
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*/
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f = __etext ;
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for( t = __data_start__ ; t < __bss_start__ ; t += 1)
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*t = *f++ ;
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while( t < &__bss_end__)
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*t++ = 0 ;
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main() ;
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for( ;;) ;
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}
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/** Test code: main.c *********************************************************/
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const char hexa[] = "0123456789abcdef" ;
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long first = 1 ;
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long i ;
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int main( void) {
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static char c = 'a' ;
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char *cp = &c ;
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*cp += i ;
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i += hexa[ 13] - c + first++ ;
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return 0 ;
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}
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/* end of cstartup.c */
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