.equ loop_count = 62
.def iH = r25
.def iL = r24
.def countH = r17
.def countL = r16

.macro halfSecondDelay
ldi countL, low(loop_count) ; 1 cycle
ldi countH, high(loop_count)
clr iH ; 1
clr iL
loop: cp iL, countL ; 1
cpc iH, countH
brsh done ; 1, 2 (if branch)
adiw iH:iL, 1 ; 2
nop
rjmp loop ; 2
done:
.endmacro