Break Out of the Middle of a While Loop

Scenario: I'm updating my Boot Alarm and part of this process is turning the alarm into a song. Before, the alarm would do quick repeating cycles and it would check to see if it was disarmed after each cycle. However, with a song, the cycle becomes much, much longer. An interrupt is generated and the status is changed but I would like to break out of the song as soon as the disarm signal is sent, not after the entire song is done and it checks the status again.

Question: Is there a way to break out of the while loop as soon as the signal is sent? Currently, I just have for() loops placed throughout the song so that it only continues for a couple of seconds after disarming. It seems... inelegant - to use the words of someone else in these forums recently.

Thanks!

- Josh

Break statement:
http://www.cprogramming.com/reference/break.html

The switch/break would work the same as the for() loop, but maybe a bit cleaner in code. It doesn't address the issue of cutting off at anytime in the code (being forced by an interrupt, perhaps?), not just when it does the regular checks. And saying that, I should have mentioned before that exactly what I'm looking for may not be possible without a significant rethinking and rewriting of my code.

Also, I don't see why someone would simply have a break statement in the middle of their code, without any sort of decision making involved, as shown as the first example on the page.

Appreciate the quick response, that was eerily fast.

I'm just making time to go to sleep early...I'm driving back home tomorrow ;)

As for the example...programming text book examples are usually like that, I don't like it either, it's not a practical example, and thus, not relatable.

Have you ever used software interrupts? That might also work.

Vacation is over? Always disappointing, tomorrow is my first day back to the normal tempo at work and I'm not looking forward to it...

Unfortunately, the way I have the code setup, my software interrupt only changes my status. I have three statuses (stati?), disarmed, armed, and alarming. Disarmed and armed are just sitting there, looping while waiting for an interrupt to change the status. When the status changes, it notices on the next loop and switches over to the while loop that associates with the status.

Here, I'll attach the heart of my code for your perusal.

[code lang="c"]
while(1) {
while(status == 0xAA) { /* Disarmed */
NOP();
}
while(status == 0xBB) { /* Armed */
RD6 = 1;
for (y = 1; y

It IS late, and my eyes are bleary from coding my own C tonight, so this may not make as much sense as I'd like:

There is not quite enough info for me to figure out which while loop you want to break out of.
It is the main while(1) loop, or the while that the siren() call is in, or is there some while within siren()?

I'm assuming that siren() is the call to what is now your song.
And I'm assuming that the for loops in siren() are also testing for the alarm status.

If the second assumption is correct, then does PIC allow siren() to return a value?
If so, then you could rewrite the call to be:

if ((returnvar = siren()) == 0xWhichever)
break;
}

You could then also immediately test returnvar below the siren() while loop:

if ((returnvar = siren()) == 0xWhichever)
break;
}
if (returnvar == 0xWhichever)
break;
} /* end of while(1) */

... and then you'd be out of all the whiles.

I have a LinkedIn connection to a PIC programmer, so ultimately we could bring in his clear head.

- Inelegant Bob

Well, the eeweb comment server killed my line breaks in my C examples.
Also removed one of the double-equals signs for some reason even though I cut and pasted from notepad.

Still, I think you can get the idea.

You'll have to tell us how you got your code to format so nicely - eeweb didn't crush it like it did mine...

That is, removed ALL the equality tests in ONE of the lines is what I meant. Aargh.

It seems you have 2 options:

1. Check the status at regular intervals in siren() - assuming this is playing the song. Not a very elegant solution.
2. Change the program structure (a little?) so the song is played by a timer interrupt, i.e. the timer interrupt rolls over
at a convenient rate (maybe a note interval), plays the next note and checks the status. If the status has changed it
aborts the song immediately. (If you set this at a high constant rate, you can also use this for delays of course.)

Let us know what you decide and how it turns out...

You are correct, within siren() is the while() loop that I would like to break out of. And I could have siren() return a value if I wanted it to. I think this still has the same issue that it is only checking the status at the end of the while() loop [i.e. siren() function] and then making a decision at the end of the function as to whether or not it should jump back in and execute the entire function over again.

I'm honestly thinking that exactly what I'm looking for is not possible, which is kinda what I thought in the first place, I just wanted to ask someone smarter than me.

Also, for the code formatting, at the top of the textbox where I'm typing this is a line of formatting options (headers, bold, italics, strikethrough, etc..) At the right end of the line there is what looks like a piece of paper with on it. Click on that and you'll be good to go!

Pieter, I'm currently implementing the first option but the second option is interesting. I think I see how I could do it. In the twelve hours since I posted this question, though, I've already decided that the first option is good enough for this project. I'm still interested in the answer for future projects, but I'm done with this boot. I'll try and get some good documentation posted on this site when I finish with the second version, see if anyone else enjoys its ridiculousness.

Thanks for your help! I'm going to bed...

The right-most button above the textarea (looks like a piece of paper with '' symbols on it) can be used to insert code blocks with highlighting for various languages. Relatively new feature.

Josh - I know you said you were done with the boot code and that's fine, programmers are like sharks: gotta keep moving.
But Pieter's idea about single notes got my subconscious working on an "elegant" (hopefully) approach.

Besides, I wanted to try out the tag to format some code ;^)

So, say your song has 30 notes...


[code lang="c"]
/* somewhere inside siren() */

int pitch[30] = {440,660,300,440, blah...};
int duration[30] = {1,2,2,4, blah...};
int play_song = 1;

while (play_song) {
for (j=0; j