It depnds on what sort of accuracy you need. If it is just a rough gating effect you need then a loop counter will get you there.

PIN_dur var byte

PIN_dur = 0
While Input_Trigger = 0
pause 10 ;10mS pause
if PIN_dur != 255 ;Check time delay isn't 255
PIN_dur = PIN_dur + 1 ;Or it rolls over back to zero
Endif
Wend

Stored in PIN_dur, now, is the number of 10mS periods the button was held down for.

100 x PIN_dur = approx 1 second

If PIN_dur >100 then
goto/gosub long press code
else
goto/gosub shorter press code
endif

You could also use the PULSIN command which measures pulse lengths. Reading the result into a 16-bit variable, and at 4MHz, you can accurately measure to about 0.65 seconds, so yoiu would need to call it twice to get a 1 second push (and gate off the first reading)

Chris