Creates a block of code that is executed non-atomically. Upon entering the block the Global Interrupt Status flag in SREG is enabled, and disabled upon exiting the block from any exit path. This is useful when nested inside ATOMIC_BLOCK sections, allowing for non-atomic execution of small blocks of code while maintaining the atomic access of the other sections of the parent ATOMIC_BLOCK.

Two possible macro parameters are permitted, NONATOMIC_RESTORESTATE and NONATOMIC_FORCEOFF.