2.1.5 NONATOMIC_RESTORESTATE

This is a possible parameter for NONATOMIC_BLOCK. When used, it will cause the NONATOMIC_BLOCK to restore the previous state of the SREG register, saved before the Global Interrupt Status flag bit was enabled. The net effect of this is to make the NONATOMIC_BLOCK's contents guaranteed non-atomic, without changing the state of the Global Interrupt Status flag when execution of the block completes.