RE: RE: [avr-gcc-list] for loop problem

[Adrian Cottle]

I've tryed putting a asm("NOP") into the for loop and this doesnt cure the 
problem.
Im not sure which optimization im using, I have the studio set up with 
gccavr with the intructions from AVR Freaks.

thanks

Adrian

-----Original Message-----
From:   Volkmar Dierkes [SMTP:address@hidden
Sent:   17 January 2003 12:55
To:     address@hidden; AVR Emailing List (E-mail)
Subject:        Re: RE: [avr-gcc-list] for loop problem

Adrian,

what is the exact problem? Does it hang in the loop (I can't imagine) or 
does gcc optimize the loop to nothing (deleted it)? In the last case it 
might be neccessary to include a
asm("nop");
(instead of your msdelay(1)) in the loop. With this it shouldn't delete it. 
Maybe there are other/better ways, but I think this should help. And even 
sometimes it helps if you look at the generated code what the compiler 
creates. Which optimization level do you using?

Volkmar

"address@hidden" <address@hidden> schrieb am 17.01.03 
13:40:33:
>
> I have tryed changing the flag rto static volatile and volatile. this 
seems
> to have corrected the UART loop problem but not the other loop problem
>
> while(Timeout_Flag != 0xFF && Element_Pulse_Flag != 0xFF)
>   {
>       int i;
>       for(i=0;i<10;i++)
>       {
>       //msdelay(1);
>       }
>
>   }
>
> this still needs the delay in to work
>
> any idea?
>
> thanks
>
> adrian
>
>
> Adrian,
>
> > I have the function below (well part of it) and it waits in a loop 
until
> > the UART flag is flagged.  If i put a 100ms delay in or do something 
like
> > send a byte to the uart it works fine, but as soon as i leave a empty 
for
> > loop it crashed and needs resettting.
> ...
> > int Pulse_Handler(void)
> > {
> > int i;
> > uart_send_byte(33);
> >   while(UART_Flag == 0)
> >   {
> >     msdelay(1);
> >  //uart_send_byte(46);
> >   }
> >   UART_Flag = 0 ;                           
> >   uart_send_byte(85);
>
> You need to define UART_Flag as volatile. If you look at the generated 
code
> you can see that without volatile it checks only once for UART_Flag and
> runs than into an endless loop. With the volatile you can see that the
> compare is included into the loop.
>
> Volkmar
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You should carry out your own virus checks before opening any attachment.  Any 
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