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#include <avr/io.h>
#include <avr/interrupt.h>
#undef _SFR_IO8
#define _SFR_IO8(x) (x)
#undef _SFR_IO16
#define _SFR_IO16(x) (x)
.global main
main:
in r11, SPH ; save stack pointer
ldi r16, 0xff
out SPH, r16 ; kill stack pointer
sei ; enable interrupts, attention: stack is not in place!
ldi r16, (1<<UDRIE) ; lets generate a usart data register empty irq
out UCSRB, r16 ; which should exactly now take place BUT ->
out SPH, r11 ; the avr should do one more instruction after irq vector raise! always!
ret ; this will result in going back to ctors_end -> exit
.global USART_UDRE_vect
USART_UDRE_vect:
ldi r16, ~(1<<UDRIE)
out UCSRB, r16
.global stopsim
stopsim:
reti
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