A way to do this without interrupts:

<pre>


#define BUTTON_PRESSED (!debounce_ctr)
uint debounce_ctr = 1000;

if (!pushb) debounce_ctr = 1000; //reload if not pressed

if (debounce_ctr) debounce_ctr--; // count down if pressed

if (BUTTON_PRESSED) ..... so something if button is pressed

The value of 1000 here should depend on the cycle time of this program:
if this is 50 uS you get a debounce time of 50 mS.
Of course, a better way is to do the count down in a timer interrupt
routine, so the cycle time is not important anymore.

Lex.