5 ms·

Fantastic tool for compiling x86 assembly code but I've grown to like GNU gas and its at&t syntax. Which do you prefer?

pjmlp 5y ago
Intel, I ported my toy compiler Assembly generation from Intel to AT&T back when it wasn't yet supported on gas, never again.
guerrilla 5y ago
In case anyone doesn't know, gas supports Intel syntax now.
- pjmlp 5y ago
  Last time I read about it, the support was only partial, but I cannot remember the details.
  - guerrilla 5y ago
    I wrote a robust-ish bootloader and didn't notice anything missing. It's only the macro/prelude code that differs but that does among all assemblers.
xbar 5y ago
Intel. AT&T is immoral.
- mrlonglong 5y ago
  Why?
  - xbar 5y ago
    https://outerproduct.net/2021-02-13_att-asm.html https://outerproduct.net/2021-02-13_att-asm.html
    - userbinator 5y ago
      Also the slightly earlier http://x86asm.net/articles/what-i-dislike-about-gas/ http://x86asm.net/articles/what-i-dislike-about-gas/
msla 5y ago
Intel. I can't bring myself to learn this: movl mem_location(%ebx,%ecx,4), %eax on any architecture where assemblers also support this: mov eax, [ebx + ecx*4 + mem_location]
- mrlonglong 5y ago
  Either works for me, I'm easy. Besides I cut my teeth on m68k and x86, and I do like how it keeps it easy with things like mov.b, mov.w and mov.l - keeps things clear what you're working with.
- messe 5y ago
  Agreed. I like `mov %src, dst` more than `mov [dst], src`, but GAS's `seg:disp(base, index, scale)` is insanity compared to Intel syntax.
  - Galanwe 5y ago
    Would you agree that it makes more sense though? I tend to agree with you, I _want_ to write 'mv src, dst', but the other way around has some strong supporting reasons: - it's closer to the usual pseudo assembly "eax <- ebx" - it's closer to the mathematical "A = B" - on a more practical side, it's what was adopter by C standard library "memcpy(dst, src)" Thinking about it, there are more reasons to favor 'mov dst, src'. I think the culprit (at least for me) is that I cannot "pronounce" it correctly in my head. I have to use some peripheral sentence such as "move in dst the contents of src" instead of the more natural (but backward from the reading perspective) "move src to dst"
    - rhn_mk1 5y ago
      Nitpickery, but in the mathematical notation A = B is not an assignment (and is exactly the same as B = A). Assignment is more clearly written as A := B, but I never saw this as a maths thing, but as a programming convention.
- mrlonglong 5y ago
  Does movl mem(%ebx + %ecx + 4), %ecx also work? If so that would read better than with the commas. (Sorry, can't quite recall how to get code snippet markup to work)
flykespice 5y ago
Intel is much more intuitive than At&t's (if at all)

Intel, I ported my toy compiler Assembly generation from Intel to AT&T back when it wasn't yet supported on gas, never again.

guerrilla 5y ago

In case anyone doesn't know, gas supports Intel syntax now.

pjmlp 5y ago
Last time I read about it, the support was only partial, but I cannot remember the details.
- guerrilla 5y ago
  I wrote a robust-ish bootloader and didn't notice anything missing. It's only the macro/prelude code that differs but that does among all assemblers.

xbar 5y ago

Intel. AT&T is immoral.

mrlonglong 5y ago
Why?
- xbar 5y ago
  https://outerproduct.net/2021-02-13_att-asm.html https://outerproduct.net/2021-02-13_att-asm.html
  - userbinator 5y ago
    Also the slightly earlier http://x86asm.net/articles/what-i-dislike-about-gas/ http://x86asm.net/articles/what-i-dislike-about-gas/

msla 5y ago

Intel. I can't bring myself to learn this: movl mem_location(%ebx,%ecx,4), %eax on any architecture where assemblers also support this: mov eax, [ebx + ecx*4 + mem_location]

mrlonglong 5y ago
Either works for me, I'm easy. Besides I cut my teeth on m68k and x86, and I do like how it keeps it easy with things like mov.b, mov.w and mov.l - keeps things clear what you're working with.
messe 5y ago
Agreed. I like `mov %src, dst` more than `mov [dst], src`, but GAS's `seg:disp(base, index, scale)` is insanity compared to Intel syntax.
- Galanwe 5y ago
  Would you agree that it makes more sense though? I tend to agree with you, I _want_ to write 'mv src, dst', but the other way around has some strong supporting reasons: - it's closer to the usual pseudo assembly "eax <- ebx" - it's closer to the mathematical "A = B" - on a more practical side, it's what was adopter by C standard library "memcpy(dst, src)" Thinking about it, there are more reasons to favor 'mov dst, src'. I think the culprit (at least for me) is that I cannot "pronounce" it correctly in my head. I have to use some peripheral sentence such as "move in dst the contents of src" instead of the more natural (but backward from the reading perspective) "move src to dst"
  - rhn_mk1 5y ago
    Nitpickery, but in the mathematical notation A = B is not an assignment (and is exactly the same as B = A). Assignment is more clearly written as A := B, but I never saw this as a maths thing, but as a programming convention.
mrlonglong 5y ago
Does movl mem(%ebx + %ecx + 4), %ecx also work? If so that would read better than with the commas. (Sorry, can't quite recall how to get code snippet markup to work)

flykespice 5y ago

Intel is much more intuitive than At&t's (if at all)