With the folowing lines an input pin gives a pulse during 1 complete program cycle and a new pulse wil be generated after changing the input state back to 0 and brought back to 1 again yust what you want.

HULP0 VAR BIT
PULSE VAR BIT

INPUTPIN VAR PORTX.Y

PULSE = INPUTPIN & ~ HULP0
HULP0 = INPUTPIN

succes with it.