Status Register and Boolean Formula

I T H S V N Z C
S
N ⊕ V, for signed tests.
V

R7 • R6 • R5 • R4 • R3 • R2 • R1 • R0

Set if two’s complement overflow resulted from the operation; cleared otherwise. Two’s complement overflow occurs if and only if Rd was $80 before the operation.

N

R7

Set if MSB of the result is set; cleared otherwise.

Z

R7R6R5R4R3R2R1R0

Set if the result is $00; cleared otherwise.

R (Result) equals Rd after the operation.

Example:

 ldi r17,$10 ; Load constant in r17
loop: add r1,r2 ; Add r2 to r1
 dec r17 ; Decrement r17
 brne loop ; Branch if r17<>0
 nop ; Continue (do nothing)
Words
1 (2 bytes)
Cycles
1