8-bit AVR Microcontrollers

Status Register

The Status register contains information about the result of the most recently executed arithmetic instruction. This information can be used for altering program flow in order to perform conditional operations. The Status register is updated after all ALU operations, as specified in the instruction set reference. This will in many cases remove the need for using the dedicated compare instructions, resulting in faster and more compact code.

The Status register is not automatically stored when entering an interrupt routine and restored when returning from an interrupt. This must be handled by software.