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Index > Macroinstructions > Cannot local,inside macro nested in macro definition

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hopcode



Joined: 04 Mar 2008
Posts: 563
Location: Germany
hopcode
[Compiler internals ?]
Hallo all,
I wonder wheather is there a way to create an
unique local scoped label in a macro which is
inner and nested in an outer, during its definition stage.
It is to say:
if i write:

Code:
macro external val,prefix,arg {
 local ..tmp
 val equ prefix#..tmp#arg

 display `prefix#`..tmp#`arg
 display 13,10
 ;<---- it displays id@outer?Pj..tmp?Pk1a
 ;<---- and then    id@outer?Pj..tmp?Pl1a
}

macro outer {
 local id@outer
 retval equ
   
macro inner arg,userlabel \{
  external retval,id@outer,arg
  retval:            ;<- no "symbol already defined" error
    nop                   ;isnt it not strange ?
  jmp retval
  userlabel equ retval
  \}
}
  outer
   inner a,lab1_a
   inner a,lab2_a
                       
   jmp lab1_a
   jmp lab2_a
    


output code:
Code:
0x402000: 90     NOP          
0x402001: EBFD   JMP 0x402000 
0x402003: 90     NOP          
0x402004: EBFD   JMP 0x402003 
0x402006: EBF8   JMP 0x402000 
0x402008: EBF9   JMP 0x402003 
    


I obtain almost the desired code.
But, if i write
Code:

macro outer {
 local id@outer
   
 macro inner userlabel \{
  local retval
   display \`retval    ;it display always the same name
   display 13,10    ;i.e. retval?Pk

;  ;----decommenting the following line....
;  ;retval:
;  ;----causes "symbol already defined" error

  retval equ $  ;<- but this line would act as it was "define retval $"
   nop
   nop
 jmp retval
 userlabel equ retval
 \}
}
    


In this last way of writing...
(impossible to compile without error)
Code:

macro outer {
 local id@outer
   
 macro inner userlabel \{
  local val     ;<-- i would like to write this line without let raising an error... 
  val:          ;... in order to obtain an UNIQUE+LOCALSCOPED label
   nop
   nop
  userlabel equ val
 \}
}
  outer
   inner lab1
   inner lab2
    jump lab1
    jump lab2

    


Please,follow me now in this little logik...

1- "id@outer", local, is visible in the macro inner. "val" is invisible for "outer".
and normally invisible in not-nested macro, where it has unicity and limited scope.

2- but "val" is not completely local here, because it lacks of unicity everytime i invoke
the macro "inner" after, and only after, invoking once "outer".

3- last but not least, i cannot "purge inner" outside his definition, after but always during the definition
of "outer" to force creation of an unique "val" everytime and after the invoked "inner".


Why so ?
How can i get a fully qualified local label (i.e. unic and scope-limited) during
the definition of a macro inside a macro ?
Post 03 Sep 2008, 10:49
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17450
Location: In your JS exploiting you and your system
revolution
I think you need to escape local inside the macro with a backslash.

Try this:
Code:
macro outer {
 local id@outer
   
 macro inner userlabel \{
  \local retval  ;<-- it is now escaped
   display \`retval     ;it display always the same name
   display 13,10        ;i.e. retval?Pk

;  ;----decommenting the following line....
;  ;retval:
;  ;----causes "symbol already defined" error

  retval equ $  ;<- but this line would act as it was "define retval $"
   nop
   nop
 jmp retval
 userlabel equ retval
 \}
}    
Post 03 Sep 2008, 11:19
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hopcode



Joined: 04 Mar 2008
Posts: 563
Location: Germany
hopcode
Yes!!!!!!
It works !!!
How can i be so sleepy ? Embarassed
Should i not reinvent the Art of Modern Spleeping ?
..AMS Art of Modern Sleeping...
..AMSOS Art of Modern Sleeping Operating System
...
i owe you thousand thanx,revolution,
for the quick and precise answer...
hopcode[mrk]
Post 03 Sep 2008, 12:30
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17450
Location: In your JS exploiting you and your system
revolution
I'll send you the bill in the mail Wink
Post 03 Sep 2008, 13:20
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