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Mino



Joined: 14 Jan 2018
Posts: 133
Hello Smile ,
I have 3 questions, but I'm only going to create one post, because they are more or less related (I think). So without further ado:

    - What are "passes"? I mean, when we compile, a small dialog box (under the fasm IDE) displays us, for example: "2 passes, 1536 bytes". I would like to know exactly what these passes are.
    - How do I retrieve the final code that was produced by the compiler (if I'm not mistaken, it's x86-64, or directly from "binary"instructions)?
    - How to make variables ('. data' section) belong to a label? So that they can't be used any other way? This question is to my liking, the most "eccentric", but basically: I would like to see if it is possible to do as in the higher-level languages, create a variable/block membership (labels in this case).


I already thank you for your help:)
Have a pleasant end of the day!

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Post 24 Feb 2018, 15:12
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ManOfSteel



Joined: 02 Feb 2005
Posts: 1146
Mino wrote:
What are "passes"? I mean, when we compile, a small dialog box (under the fasm IDE) displays us, for example: "2 passes, 1536 bytes". I would like to know exactly what these passes are.

http://flatassembler.net/docs.php?article=manual#1.1
http://flatassembler.net/docs.php?article=design
https://en.wikipedia.org/wiki/Multi-pass_compiler

Mino wrote:
How do I retrieve the final code that was produced by the compiler (if I'm not mistaken, it's x86-64, or directly from "binary"instructions)?

Disassemble the output, I guess.
Post 25 Feb 2018, 10:51
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Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 6876
Location: Kraków, Poland
ManOfSteel wrote:
Mino wrote:
What are "passes"? I mean, when we compile, a small dialog box (under the fasm IDE) displays us, for example: "2 passes, 1536 bytes". I would like to know exactly what these passes are.

http://flatassembler.net/docs.php?article=manual#1.1
http://flatassembler.net/docs.php?article=design
https://en.wikipedia.org/wiki/Multi-pass_compiler
I have recently written a short text that discusses the multi-pass assembly in detail: https://board.flatassembler.net/topic.php?t=20249
Post 25 Feb 2018, 10:58
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Mino



Joined: 14 Jan 2018
Posts: 133
Thank you very much for your links, I have now understood the principle of multiple pass compilation.
Otherwise, for the disassembler, it doesn't really correspond to my needs, but it's true that I can deal with it.
PS: You still don't have any ideas for variable belonging to a label Very Happy ?
Post 25 Feb 2018, 11:59
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Furs



Joined: 04 Mar 2016
Posts: 1175
Mino wrote:
PS: You still don't have any ideas for variable belonging to a label Very Happy ?
There is no such thing. A label is just a reference to a memory location, it doesn't exist in the compiled executable. (you won't see it when disassembled, probably the disassembler will give you a "placeholder" label, with a generated name like L42)
Post 25 Feb 2018, 13:20
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Mino



Joined: 14 Jan 2018
Posts: 133
Yes, indeed, after a disassembly of the executable, the label does not exist, as you said, it is only a "marker" of position in the memory. But I'd like to know if there's a trick to make it look like it is.
After that, I could probably do it, but in a pretty "poofy"way. That's why I would like to know if there is a standard, or a better way to achieve a similar result:)
Post 25 Feb 2018, 14:56
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donn



Joined: 05 Mar 2010
Posts: 105
There is also the LISTING.inc tool in the fasm TOOLS dir, may provide some more insight. The README provides a description of LISTING.inc and its usage.
Post 25 Feb 2018, 15:00
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fasmnewbie



Joined: 01 Mar 2011
Posts: 518
Quote:
PS: You still don't have any ideas for variable belonging to a label


Code:
Label1: .myLabel dq 0 Label2: .myLabel dd 4 mov rax,[Label1.myLabel] mov ebx,[Label2.myLabel]
Post 25 Feb 2018, 17:12
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Mino



Joined: 14 Jan 2018
Posts: 133
When I do this (using a valid code), it tells me that your line 6 is an illegal instruction.
Is that normal?
Post 25 Feb 2018, 17:35
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CandyMan



Joined: 04 Sep 2009
Posts: 269
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop
"rax" is 64-bit register available only in 64-bit mode. you must define bitness of code using directive "use64" (default code bitness in fasm is 16-bit).
Code:
use64 ... ;your 64-bit code

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Last edited by CandyMan on 25 Feb 2018, 17:56; edited 1 time in total
Post 25 Feb 2018, 17:52
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fasmnewbie



Joined: 01 Mar 2011
Posts: 518
Because you're using 32-bit code. Snippet above is for 64-bit. But regardless, that's what you meant by "variable belonging to a label".
Post 25 Feb 2018, 17:55
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Mino



Joined: 14 Jan 2018
Posts: 133
Thank you very much for all your answers:)
I would like to know one last thing, what changes from 16-bit mode to 64-bit mode? Apart from, of course, the use of some registers or other...
Post 26 Feb 2018, 16:30
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CandyMan



Joined: 04 Sep 2009
Posts: 269
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop
Post 26 Feb 2018, 17:29
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Mino



Joined: 14 Jan 2018
Posts: 133
Thank you for everything Smile
Post 26 Feb 2018, 17:50
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