power fail interrupt on NIOS2 and LPC2106

I am busy with a design of an embedded system with Altera Cyclones with NIOS

2 and a LPC2106 ARM cpu. Have implemented RTC with battery backup, nonvolatile 32kB sram (simtek), a LTC2901 reset controller and a double window watchdog timer in a ATtiny11. I also want to implement a power failure interrupt to the NIOS 2 cpu and the LPC2106 arm. Questions: 1-which interrupt should i use on the NIOS2 and the LPC for power faillure??, i cannot find the equivalent of the NMI interrupt as on the old Z80... 2-How can i prevent garbling up the data during writes to the nonvolatile sram when a power faillure hits??

regards

Ron Proveniers