9 GPR - General Purpose Registers

The AVR128DB28/32/48/64 devices provide four General Purpose Registers. These registers can be used for storing any information, and they are specifically helpful for storing global variables and interrupt flags. No implicit or explicit semantic applies to the bits in the General Purpose Registers. The interpretation of the bit values is determined by software.

General Purpose Registers, which reside in the address range 0x001C - 0x001F, are directly bit-accessible using the SBI, CBI, SBIS, and SBIC instructions.