How to rewrite [es:di] to att syntax

Question

This is a short question but I did not manage to find the answer online.

How do you rewrite mov [es:di], dl into AT&T syntax?

I use it to write a pixel to the screen in real mode.

You can always assemble something with nasm and disassemble it with `objdump -drwC` to get the AT&T disassembly of the machine code. — Peter Cordes, Sep 21 '18 at 06:52
@MichaelPetch when i do that, i get the error: '%es:(%di)' is not a valid base/index expression — Bisccit, Sep 21 '18 at 17:12
The only reason that would be an invalid expression is if you are generating this as 64-bit code. Using a 16-bit register in a memory operand in 64-bit code is not supported. — Michael Petch, Sep 21 '18 at 17:15

score 2 · Answer 1 · answered Feb 23 '22 at 11:14

2

mov %dl, %es:(%di):

In the AT&T Syntax, memory is referenced in the following way:

segment-override:signed-offset(base,index,scale)

parts of which can be omitted depending on the address you want.

%es:100(%eax,%ebx,2)

A corresponding Intel syntax indirect memory reference:

segment-override:[base + index*scale + signed-offset]

es:[eax + ebx*2 + 100]

answered Feb 23 '22 at 11:14

Ernie Sanderson

1

For NASM the segment override goes either inside the brackets (`[es:di]` like in the question) or before the instruction (`es lodsb`). – ecm Feb 23 '22 at 14:23

1 Answers1