addressing-mode – Tarik Billa

What does an asterisk * before an address mean in x86-64 AT&T assembly?

December 22, 2023 by Tarik

It’s AT&T assembly syntax: source comes before destination mnemonic suffixes indicate the size of the operands (q for quad, etc.) registers are prefixed with % and immediate values with $ effective addresses are in the form DISP(BASE, INDEX, SCALE) (DISP + BASE + INDEX * SCALE) Indirect jump/call operands indicated with * (as opposed to … Read more

How to use RIP Relative Addressing in a 64-bit assembly program?

September 23, 2023 by Tarik

I believe that you want to load the address of your string into %rsi; your code attempts to load a quadword from that address rather than the address itself. You want: lea msg(%rip), %rsi if I’m not mistaken. I don’t have a linux box to test on, however.