label with no value, no namespace but if defined

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edfed

Joined: 20 Feb 2006
Posts: 4353
Location: Now

edfed 30 Mar 2023, 21:54

i was wondering how it can be possible to make something like this

Code:


thisLabelHaveAValue=1
thisOneAlso:
.thisIsLocalForAlso:
.thisIsLocalTooForAlso=1

butNow:
IwantItToBeALAbelWithoutValue.
.andThisToBeLocalForbutNow:

for example, a no value label can be a label ending by a single dot, or anything else.
and now a more readable example:

Code:

Label1=1

mov al,Label2.local6


Label2:
.local1:
        db '1'
.local2=2
.local3.
Global1.
.local4:
Global2.
if defined Global1
.local5=5
end if
.local6 db 6

of course, it is just for comfort.
using conventionnal labels is enough, but label with no value can be interresting.

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30 Mar 2023, 21:54

bitRAKE

Joined: 21 Jul 2003
Posts: 4071
Location: vpcmpistri

bitRAKE 30 Mar 2023, 22:51

Here I extend the example from the fasmg documentation:

Code:

postpone
namespace GLOBAL
        element NOVALUE
        irpv G,GLOBAL
                label G:NOVALUE at NOVALUE
        end irpv
end namespace
end postpone

struc (head) ? tail&
        match ,tail
                display 10, `head," is NOVALUE"
                define GLOBAL head
                macro ? line&
                        purge ?
                end macro
        end match
        head tail
end struc


dd Main.local_to_main
Main:
        undefined_labels_have_no_value
        IwantItToBeALAbelWithoutValue
        .local_to_main:

... I put all the undefined labels in a special GLOBAL space so they don't interfere with local labels, and make them variable terms so they can't be used in calculations. Perhaps there is more to your requirements?

30 Mar 2023, 22:51

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20445
Location: In your JS exploiting you and your system

revolution 31 Mar 2023, 00:36

The double dot is for global labels not attached to a preceding label.

Code:

label1:
..global1:
.local1:
..global2:

31 Mar 2023, 00:36

Roman

Joined: 21 Apr 2012
Posts: 1847

Roman 31 Mar 2023, 07:57

revolution wrote:

The double dot is for global labels not attached to a preceding label.
Code:
label1:
..global1:
.local1:
..global2:    

This is work in Fasmw 1.73 too?

31 Mar 2023, 07:57

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20445
Location: In your JS exploiting you and your system

revolution 31 Mar 2023, 08:34

Roman wrote:

revolution wrote:
The double dot is for global labels not attached to a preceding label.
Code:
label1:
..global1:
.local1:
..global2:    
This is work in Fasmw 1.73 too?

Yes. my answer is for fasm. fasmw is the IDE editor which uses fasm internally, so it will work for fasmw also.

Try it.

31 Mar 2023, 08:34

edfed

Joined: 20 Feb 2006
Posts: 4353
Location: Now

edfed 01 Apr 2023, 00:13

cool very cool. i'll use it

but what i suggest is a label withou any value attached to it.

like:

Code:


Global.

mov eax,Global;impossible to do

if defined Global
display 'yes'
end if

if Global=3
impossible to know
end if

Global.;no error even if still defined

if Global eq
display 'yes it exists'
end if


if Global ~eq
impossible to know 
end if

something like that.
but of course, the negative conditions are not mandatory. the only condition to have is a label without value attached to it, and global, and reccursive, and don't care if still defined

01 Apr 2023, 00:13

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20445
Location: In your JS exploiting you and your system

revolution 01 Apr 2023, 01:39

Assign no value.

Code:

Global =

What purpose will it serve? Where is it useful?

01 Apr 2023, 01:39

macomics

Joined: 26 Jan 2021
Posts: 1040
Location: Russia

macomics 01 Apr 2023, 07:01

Code:

struc global
{   if 0
        label .
    end if
}

Label1=1

mov al,Label2.local6


Label2:
.local1:
        db '1'
.local2=2
.local3 global
Global1 global
.local4:
Global2 global
if defined Global1
.local5=5
end if
.local6 db 6

01 Apr 2023, 07:01

edfed

Joined: 20 Feb 2006
Posts: 4353
Location: Now

edfed 01 Apr 2023, 10:38

it is to have an intuitive and easy to use boolean flag useable during preprocessing.
not the same as

label equ thing
label:
label= thing

cause theses still have a purpose.

Code:

DEBUG:

if DEBUG
mov eax,thing
end if

for the moment, the best fit is

label:

but it have a scope, and i don't care the value assinged to it.

and it needs something around to if that

Code:

if defined DEBUG
end if

01 Apr 2023, 10:38

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20445
Location: In your JS exploiting you and your system

revolution 01 Apr 2023, 11:42

Why must it have no value?

Code:

DEBUG = 0 ; don't want debug
;...
DEBUG = 1 ; gimme the debugs
;...

01 Apr 2023, 11:42

edfed

Joined: 20 Feb 2006
Posts: 4353
Location: Now

edfed 01 Apr 2023, 19:36

I want to put it anywhere, and don't need it to be defined if i don't want it in the code.
if i write a

if VAR

no error and for a

mov eax,var

error cause it is an internal compiler flag

hem.. now it makes all sense, if i don't need a value for a label, how to react to a undefined value...

01 Apr 2023, 19:36

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