[avr-gcc-list] Bootloader question

[Scott Morken]

Hi

I have an application that jumps to the bootloader using this function 
(it's a slightly modified avr109 bootloader made by atmel):
void (*funcptr)( void ) = (void *)0x3800; // Set up function pointer to 
the bootloader start.

I call it when a command is sent over the serial port, making this code run:
UART_SendByte('B');
wdt_disable();//disable watchdog
cli();//disable all interrupts
for(counter = 0; counter<20000; counter ++)
{
   asm("NOP");
}
                      
funcptr();//goto bootloader

It has been working great until some code was added to my application.  
Now it will not enter the bootloader properly when I send the command.  
I suspect the chip is crashing before it gets to the funcptr(); line.  I 
have narrowed down the code to about 10 lines in a timer overflow 
interrupt, when I comment it out it works fine.  Here are the suspect 
lines. All of the arrays are floats and the capital letter variables are 
integers:

   if ((mod3 % 40) == 0)    //we are here 25x per second, for 25Hz 
sampling rate filter code
   {

      
       //1st order, 7Hz -3dB lowpass, 25Hz sampling filter
       xv4[0] = xv4[1];
       xv4[1] = (float)GEN_V_DIV_ADC / 1.827271946;

       yv4[0] = yv4[1];
       yv4[1] = (xv4[0] + xv4[1]) + (-0.0945278312 * yv4[0]);

       GEN_V_DIV_ADC_FILTERED = yv4[1];




       //1st order, 3Hz -3dB lowpass, 25Hz sampling filter
       xv5[0] = xv5[1];
       xv5[1] = (float)SUPERCAP_DIV_ADC / 3.525711689;

       yv5[0] = yv5[1];
       yv5[1] = (xv5[0] + xv5[1]) + (0.4327386423 * yv5[0]);

       SUPERCAP_DIV_ADC_FILTERED = yv5[1];

      

   }

Does anyone know of a reason why it would crash?

Scott