What does the bracket in `movl (%eax), %eax` mean?
%eax is register EAX; (%eax) is the memory location whose address is contained in the register EAX; 8(%eax) is the memory location whose address is the value of EAX plus 8.
addressing-mode
Understanding %rip register in intel assembly
RIP addressing is always relative to RIP (64bit Instruction Pointer) register. So it can be use for global variables only. The 0 offset is equal to address of the following instruction after the RIP-addressed instruction. For example: mov al,[rip+2] al=53 jmp short next (length=2 bytes) db 53 next: mov bl,[rip-7] (length=6 bytes) bl=53 You wouldn’t … Read more
How to use RIP Relative Addressing in a 64-bit assembly program?
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.
Do terms like direct/indirect addressing mode actual exists in the Intel x86 manuals
There aren’t really official names for most forms of x86 addressing modes. They all have the form [base + index*scale + disp8/disp32] (or a subset of any 1 or 2 components of that), except for 64-bit RIP-relative addressing. See Referencing the contents of a memory location. (x86 addressing modes) for a breakdown of what you … Read more
Differences between general purpose registers in 8086: [bx] works, [cx] doesn’t?
On the 8086 (and 16-bit addressing in x86), only addressing modes of the form [bp|bx] + [si|di] + disp0/8/16 are available. Listing them all: [bx] [bx + foo] [foo] [bp + foo] [si] [si + foo] [di] [di + foo] [bx + si] [bx + si + foo] [bx + di] [bx + di + … Read more
A couple of questions about [base + index*scale + disp] and AT&T disp(base, index, scale)
Answer recommended by Intel