What is the "last global label"?

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Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 00:11

Hey

Code:

   Main:
if 1=2
   Second:
end if
      .subname:

How to prevent Second.subname instead of Main.subname label?

05 Aug 2022, 00:11

bitRAKE

Joined: 21 Jul 2003
Posts: 4121
Location: vpcmpistri

bitRAKE 05 Aug 2022, 01:11

Do you mean:

Code:

   Main:
if 1=2
   ..Second:
end if
      .subname:

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05 Aug 2022, 01:11

ProMiNick

Joined: 24 Mar 2012
Posts: 812
Location: Russian Federation, Sochi

ProMiNick 05 Aug 2022, 08:18

Yes here is breached "The label whose name begins with dot is treated as local label, and its name is
attached to the name of last global label (with name beginning with anything but dot)
to make the full name of this label."
last global label is Main, not Second, symbol Second never defined. but .subname attached to never defined symbol. As I understand last global label is last defined global label (it is intuitive assumption other should be documented because it absolutely contrintuitive).
Here only 2 ways:
fix documentation according to behavior;
or fix behavior according to documentation.

Description:	by the way fasm1 & fasmg in this case acts differently
Filesize:	35.97 KB
Viewed:	7965 Time(s)

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05 Aug 2022, 08:18

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20483
Location: In your JS exploiting you and your system

revolution 05 Aug 2022, 08:32

I guess it hinges on the definition of "last global label". The documentation makes no mention of a "defined" label.

Code:

org '0'
if 0
 x:
 .y:
end if
.z:

;display x      ; error: undefined symbol 'x'.
;display x.y    ; error: undefined symbol 'x.y'.
display x.z     ; 1 passes, 0 bytes.

05 Aug 2022, 08:32

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 09:35

Moderators renamed this thread but it is not about labels only.
Another examples:

Code:

   Main:
if 0
   somedata db ?
end if
   .sublabel:   ;  --> somedata.sublabel:

05 Aug 2022, 09:35

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20483
Location: In your JS exploiting you and your system

revolution 05 Aug 2022, 09:40

somedata is also a label.

05 Aug 2022, 09:40

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 09:47

Quote:

somedata is also a label.

Ofcourse but you know what I mean

05 Aug 2022, 09:47

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 10:08

Can I choose global label somehow back?

Code:

   Main:
define savelabel .
if 0
   somedata db ?
end if
  ; ... revert global
   .sublabel:

05 Aug 2022, 10:08

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20483
Location: In your JS exploiting you and your system

revolution 05 Aug 2022, 10:10

I think bitRAKE gave the answer above; to use double dots to avoid making a new "last global label" anchor.

05 Aug 2022, 10:10

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 10:22

Quote:

I think bitRAKE gave the answer above; to use double dots to avoid making a new "last global label" anchor.

I cannot do that

05 Aug 2022, 10:22

ProMiNick

Joined: 24 Mar 2012
Posts: 812
Location: Russian Federation, Sochi

ProMiNick 05 Aug 2022, 11:11

revolution wrote:

I think bitRAKE gave the answer above; to use double dots to avoid making a new "last global label" anchor.

I gues author wants understand what "last global label" is.
How double dots help to define "last global label" in true condition and not define in false condition?
He wants apply assembly time condition to definition of "last global label" like it works in fasmg. or will see in documentatiion that it is impossible.

_________________
I don`t like to refer by "you" to one person.
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05 Aug 2022, 11:11

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20483
Location: In your JS exploiting you and your system

revolution 05 Aug 2022, 11:26

The if is a red-herring. The "last global label" is set regardless of the condition.

The same for the double dot, it never sets the "last global label", regardless of any surrounding condition.

05 Aug 2022, 11:26

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 11:39

Quote:

I gues author wants understand what "last global label" is.

No, it's not my words, it's moderated.
I need some triks for my multisection macro.
Where subsections mixed they can mix last global labels aswell that I don't want.
1) I need to save the last global label
2) Load it back after subsection pass

Code:

   main:
... <-- savelabel somehow, I think to do that via struc
if subsection
  somedata db 0
end if
if 0
  savedlabel:     ;Load back
end if
  .sublabel:

05 Aug 2022, 11:39

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 11:51

Code:

struc getlastglobal
{ match global.rest, . \{ savedlabel equ global \} }


...
.tempvar getlastglobal
...

05 Aug 2022, 11:51

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20483
Location: In your JS exploiting you and your system

revolution 05 Aug 2022, 12:24

Label construction is done by the parser.

Struc is in the preprocessor.

The preprocessor runs first. The parser runs next.

So the preprocessor (struc) has no knowledge of label names. You can't break down label names with struc (or any other preprocessor directive (match, irp, etc.)) because the label names don't yet exist.

Also note that the assembler processes if, which is after the label is constructed. So when you think of what you are trying to do just ignore the lines with if, they make no difference at all, and just make it more confusing.

Basically there is no way to "save" the label name either before or after the parser runs.

05 Aug 2022, 12:24

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 12:36

revolution
How did my .namespace macro work then? I took the names, added marker and used that marked names. First of all I can take the names form redefined macros/struc like label,db,dd,etc

05 Aug 2022, 12:36

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20483
Location: In your JS exploiting you and your system

revolution 05 Aug 2022, 12:41

Because names are not labels. You can add names together to construct other names. But only the parser can convert names into labels.

05 Aug 2022, 12:41

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 12:55

So if labels exist the only I do is manipulating with names. Isn't it not enough for my task?

05 Aug 2022, 12:55

bitRAKE

Joined: 21 Jul 2003
Posts: 4121
Location: vpcmpistri

bitRAKE 05 Aug 2022, 14:32

Symbols are defined where they are - even in [fasmg]. Other techniques are needed to create a symbol in another context or address space. For example, create a local/double-dot symbol and then route a symbol in the desired context.

Code:

Main:
  .Second:
  .subname:


virtual at Main.Second
        Second:
end virtual

See /fasm/include/macro/proc*.inc for more complex examples - in how local variables are defined in the context of PROC.

05 Aug 2022, 14:32

Overclick

Joined: 11 Jul 2020
Posts: 670
Location: Ukraine

Overclick 05 Aug 2022, 21:32

Such a beautiful solution I've got Cool

All tested and works perfect.
If local labels used user should use one-line subsection instead of big one.

Code:

.code
   Main:
..data Somearg db 0    ;I mark it by extra dot
   .submain:

As my macro include source additional times for each global section I just skip the body of ..data subsection for wrong sections.

05 Aug 2022, 21:32

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