virtual in macro & struc offsets

Index > Macroinstructions > virtual in macro & struc offsets

Author

Thread

Blank

Joined: 28 Feb 2012
Posts: 13
Location: Ukraine

Blank 13 Mar 2012, 16:00

I create macro(it creates array with description of each member of struct) with virtual block which used to define offsets of some struct.
When I invoke this macro after struct definition - all OK, but when before - error.
As I saw in fasmpre output instance of struc in virtual block not expanded in few labels as should be.

Is there any way work around this limitation?

13 Mar 2012, 16:00

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20299
Location: In your JS exploiting you and your system

revolution 13 Mar 2012, 21:53

Show your code please. At least give us an example of what you are trying to do.

13 Mar 2012, 21:53

Blank

Joined: 28 Feb 2012
Posts: 13
Location: Ukraine

Blank 14 Mar 2012, 08:22

It's not complete code listing but, here collected all declarations needed by 'py_members'.

Code:


struc PyMemberDef name, type, offset, flags, doc {
    .name   dd name ; char*
     .type   dd type ; int
       .offset dd offset ; Py_ssize_t
      .flags  dd flags ; int
      .doc    dd doc ; char*
}

macro py_members obj,[name,type,field,flags,doc] {
common
   local i
     virtual at 0
                i obj
       end virtual
forward
      offset=i#\.#field
  local UNIQUE
        .member#UNIQUE PyMemberDef name,type,offset,flags,doc
common
     local UNIQUE
        .member#UNIQUE PyMemberDef 0,0,0,0,0
}

T_SHORT = 0
T_INT = 1
T_LONGLONG = 17

struc GUID {
  .data1 dd ?
 .data2 dw ?
 .data3 dw ?
 .data4 rb 8
}

data1_label db 'data1',0
data2_label db 'data2',0
data3_label db 'data3',0
data4_label db 'data4',0


py_members GUID_PyObject,\
    data1_label, T_INT,     guid.data1, 0, 0,\
 data2_label, T_SHORT, guid.data2, 0, 0,\
   data3_label, T_SHORT, guid.data3, 0, 0,\
   data4_label, T_LONGLONG, guid.data4, 0, 0


struc GUID_PyObject {
     .ob_refcnt dd 0
    .ob_type dd 0
        .guid GUID
}

ob GUID_PyObject

14 Mar 2012, 08:22

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20299
Location: In your JS exploiting you and your system

revolution 14 Mar 2012, 08:40

The preprocessor is not multi-pass and cannot reference definitions before they are defined. That means you can't forward reference any macros, equs or strucs.

Simple rule with preprocessor related stuff: Define first, then use.

14 Mar 2012, 08:40

Blank

Joined: 28 Feb 2012
Posts: 13
Location: Ukraine

Blank 14 Mar 2012, 08:51

Is there no tricky way to define in py_members another macro which would be expanded when preprocessor got to know what is GUID_PyObject?

14 Mar 2012, 08:51

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20299
Location: In your JS exploiting you and your system

revolution 14 Mar 2012, 09:01

Blank wrote:

Is there no tricky way to define in py_members another macro which would be expanded when preprocessor got to know what is GUID_PyObject?

Not that I know of. The virtual block can be used to give values to labels but it can't be used to give names to labels. Only the preprocessor can define the names, and only the assembler can assign the values.

Just remember that the preprocessor is not multi-pass. That should guide your coding of such things.

14 Mar 2012, 09:01

Blank

Joined: 28 Feb 2012
Posts: 13
Location: Ukraine

Blank 14 Mar 2012, 09:05

If preprocessor is not multi-pass, so sub-...-macro's expanded by one pass?

14 Mar 2012, 09:05

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20299
Location: In your JS exploiting you and your system

revolution 14 Mar 2012, 09:06

Blank wrote:

If preprocessor is not multi-pass, so sub-...-macro's expanded by one pass?

Yes.

14 Mar 2012, 09:06

< Last Thread | Next Thread >

Forum Rules:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum