How work Define in match and if ?

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Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 01 Apr 2023, 14:19

I not clearly understood how and when define applied in match branch.

Code:

macro some p {
 match x, p \{
      if x = 1      
      define _a2  50     ;What first fasm do if or define ?
      end if
      \}
}
;in code 
some 10 ;But why define _a2 applied ? If not working in this case.

And interesting, what first in macro fasm do if or define or equ ?
What is the execution order for if,equ, define ?

01 Apr 2023, 14:19

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 02 Apr 2023, 01:20

Preprocessor runs first. Assembler runs later.

You can see this in the source fasm.asm

Code:

;...
        call    preprocessor
        call    parser
        call    assembler
        call    formatter
;...

You can see the preprocessor names in the source tables.inc

Code:

preprocessor_directives:
 db 6,'define'
 dw define_symbolic_constant-directive_handler
 db 7,'include'
 dw include_file-directive_handler
 db 3,'irp'
 dw irp_directive-directive_handler
 db 4,'irps'
 dw irps_directive-directive_handler
 db 4,'irpv'
 dw irpv_directive-directive_handler
 db 5,'macro'
 dw define_macro-directive_handler
 db 5,'match'
 dw match_directive-directive_handler
 db 8,'postpone'
 dw postpone_directive-directive_handler
 db 5,'purge'
 dw purge_macro-directive_handler
 db 4,'rept'
 dw rept_directive-directive_handler
 db 7,'restore'
 dw restore_equ_constant-directive_handler
 db 7,'restruc'
 dw purge_struc-directive_handler
 db 5,'struc'
 dw define_struc-directive_handler
 db 0

There is special handling for fix and equ in the preprocessor.

Code:

;...
        cmp     eax,'fix'
        je      define_fix_constant
;...
        cmp     eax,'equ'
        je      define_equ_constant
;...

Other things like if, virtual, =, etc are in the assembler.

02 Apr 2023, 01:20

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 02 Apr 2023, 07:45

preprocessor_directives
How I understood defined do first.

02 Apr 2023, 07:45

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 02 Apr 2023, 07:54

Define is in the preprocessor.
Defined is in the assembler.

But despite the similar name they are not related in their function. They do not compliment each other.

02 Apr 2023, 07:54

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 02 Apr 2023, 08:30

Ok.
For my case its good solution?

Code:

define ap 0
match x, P \{ 
If x eq for 
define ap a+ecx
End if
\}
;if I not control when define do. I simple check define
If ap = 0
Do variant 1
End if
If ap not 0
Do variant 2
End if

And what is formatter in fasm? How work formatter?

Last edited by Roman on 02 Apr 2023, 08:38; edited 1 time in total

02 Apr 2023, 08:30

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 02 Apr 2023, 08:38

If is in the assembler. So your define ap a+ecx is always processed if the match succeeds. The If x eq for is useless and does nothing.

02 Apr 2023, 08:38

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 02 Apr 2023, 08:41

If x eq for useless.
Ok. How match finded Word for in p ?

Code:


match x =for, p {}?

02 Apr 2023, 08:41

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 02 Apr 2023, 08:47

For the preprocessor version of "if" use "match".

02 Apr 2023, 08:47

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20343
Location: In your JS exploiting you and your system

revolution 02 Apr 2023, 08:48

Do you want p (or P). matched to "for"?

Code:

match =for, p {
;...
}

02 Apr 2023, 08:48

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 02 Apr 2023, 09:12

match =for, p {} not working !

Code:

;compiled in fasmw 1.73
eggs equ for,8
;or eggs equ for 8
                ar = 0
                match =for, eggs { ar = 1 }
                match =run, eggs { ar = 2 }
                display ar+48,13,10 ;fasm show ar =0

This work fine !

Code:

macro uu p { ar = 0
match =for x, p \{ ar = 1
display 'match find for',13,10 \}     } 

eggs equ for,8
                uu eggs              
                display ar+48,13,10   ;show ar = 1               
                uu <for 11>
                display ar+48,13,10   ;show ar = 1

;this variant work too
macro uu p { define ar  0
match =for x, p \{ define ar  1
display 'match find for',13,10
\} }

02 Apr 2023, 09:12

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