What does 0x0 (r15) mean?

Question

I'm pretty avant-garde with assembler, but I don't know this, I really can't find anything about this:

cmp #0x2f44, 0x0(r15) 

what does 0x0(r15) ?

Thank you in advance!

Answer 1

This is relative addressing, which means that the offset is 0x0 from the value in register r15 .

Suppose you have a movq 8(%r15), %rax , which means moving the value stored at the address contained in r15 + offset 8 to the rax register.

A negative value of no will indicate a negative offset.