restart_cause

[Bob Milner]

Can somone explain this section of the restart_cause?
movf status,W
andlw 0x18
iorlw 0
bne xxxx

What does the iorlw 0 do?

[random_person]

movf status,W
;//moving content of Status Register to W
andlw 0x18
;//purpose is to isolate Time-Out and Power-Down status bits (for 16F87x at least...)
iorlw 0
;//purpose is to set the Z-ero flag if and only if neither a Time-Out nor a Power-Down occurred
bne xxxx
;//if Z flag was not set, this means that one or both of the "restart_cause"s occurred, so branch to xxxx


I'm pretty sure thats how you'd interpret it though I'm not at all familiar with the fuction itself

[Bob Milner]

Thanks but doesn�t the andlw do all of the logic that is
necessary for branching?

[Haplo]

Correct. 'irolw 0' basically means 'if (w==0)' or 'if(w!=0)' depending on the branch instruction coming after it.

[Guest]