Lpc2000

If my user application is running with interrupts occurring, then I 
need to disable all interrupts for a bit of time:

1) Should I use the C command "VICIntEnable=0x00000000"?
OR
2) Set the IRQ and FIQ bits in the cpsr?  Also, then do I have to be
in 
non-user mode (i.e. privileged mode) to enable/disable the IRQ/FIQ
bits 
in the cpsr?