You can find in Register TRM: http://www.cypress.com/file/136211/download
under section: 1.3.114 PICU[0..15]_INTSTAT Port Interrupt Control Status Register
INTSTAT is an 8 bit register, and each bit corresponds to each pin.
So it is " binary value of mask like (1,2,4...)"
Not sure why I did not see it there before, I had searched in TRM, maybe I had a typo during my search?