Delays in assembler and some tasks.

We often need to introduce a small delay into our programs. We often do this decrementing  or incrementing a register until it becomes a zero.

.include "m328pdef.inc"
ldi r16,1
ldi r17,1
call delay
here: nop
rjmp here
delay:
inc r16
brne delay
;rjmp here
ret

-----------------------------------some tasks----------------------------------------------

;helpful code. See below
.include "m328pdef.inc"
startprog: nop
up1:inc r5
brne up1
nop
nop
nop
inc r6
brne up1
end: rjmp end

Write short code segments in AVR Studio 4 to do the following. Put the code into your blog. Also add the relevant part of

the list file. Say how many cycles at 16MHz your segemnt used.

1) Put $16 into r16 and $17 into r17.
2) Put $11 in r11 and $12 into r12.
3) The above program takes over 49ms to get to the end: label. Say exactly how many micro-seconds.
4) Tweak number 3 above to take exactly 50ms.
5) In the Arduino we have a delay() for so many milli-seconds. Write a segment to delay r0 milli seconds. For instance if r0 contained 50 the delay would be 50ms.
6) Repeat number 4 but use dec instead of inc.
7) Write a segment to swap the contents of r0 and r1.Use specific numbers that you chose for contents.
8) Write a segment to reverse the order of the contents in r0,r1 and r2.
9) Replace any $01 in r0,r1,r2 with $ff. (Hint. Dec and check Z flag with brne or breq.)
10) Using inc, increment r0 as many times as the number in r1. Eg if r0=3 and r1= 4, then r0 would become 7.