foo.c

#include <util/atomic.h>

void blahblah();

void foo() {
    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
        blahblah();
    }
}

// avr-gcc -c foo.c -std=c99 -Os && avr-objdump -dr foo.o

output.txt

Disassembly of section .text:

00000000 <foo>:
   0:   cf 93           push    r28
   2:   cf b7           in      r28, 0x3f       ; 63
   4:   f8 94           cli
   6:   00 d0           rcall   .+0             ; 0x8 <foo+0x8>
                        6: R_AVR_13_PCREL       blahblah
   8:   cf bf           out     0x3f, r28       ; 63
   a:   cf 91           pop     r28
   c:   08 95           ret