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flat assembler > Macroinstructions > Convert fasm1 macro to fasmg (macro export dllname, [l, s])

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dunkaist



Joined: 31 Jul 2015
Posts: 11
Convert fasm1 macro to fasmg (macro export dllname, [l, s])
Hello,

I'm converting some macros to fasmg syntax and here is one I don't know how to deal with.

Code:
macro export dllname, [labelstring]
{
}


It's valid for fasm1. Unfortunately, corresponding fasmg macro doesn't work.

Code:
$ cat c.asm 
macro export dllname, [labelstring]
end macro

$ INCLUDE=/tmp/fasmg/examples/x86/include fasmg c.asm c.dll
flat assembler  version g.hoh12
c.asm [1]:
        macro export dllname, [labelstring]
Processedmacro export dllname, [labelstring]
Errorinvalid argument.

Is it possible to convert this macro in a more or less straightforward way?
Post 19 Jan 2017, 18:19
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Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 6602
Location: Kraków, Poland
I quickly prepared this more or less straightforward conversion:

Code:

macro export dllname,exports&
        iterate <label,string>, exports

                local module,addresses,names,ordinal,count
                count = %%
                dd 0,0,0,RVA module,1
                dd count,count,RVA addresses,RVA names,RVA ordinal
                addresses:
                repeat count
                        indx %
                        dd RVA label
                end repeat
                names:
                repeat count
                        dd RVA names.name#%
                end repeat
                ordinal:
                repeat count
                        dw %-1
                end repeat
                module db dllname,0
                repeat count
                        indx %
                        names.name#% db string,0
                end repeat

                local x,y,z,str1,str2,v1,v2
                x = count shr 1
                while x > 0
                        y = x
                        while y < count
                                z = y
                                while z-x >= 0
                                        load v1:dword from names+z*4
                                        str1 = ($-(RVA $))+v1
                                        load v2:dword from names+(z-x)*4
                                        str2 = ($-(RVA $))+v2
                                        while v1 > 0
                                                load v1:byte from str1+%-1
                                                load v2:byte from str2+%-1
                                                if v1 <> v2
                                                        break
                                                end if
                                        end while
                                        if v1 < v2
                                                load v1:dword from names+z*4
                                                load v2:dword from names+(z-x)*4
                                                store v1:dword at names+(z-x)*4
                                                store v2:dword at names+z*4
                                                load v1:word from ordinal+z*2
                                                load v2:word from ordinal+(z-x)*2
                                                store v1:word at ordinal+(z-x)*2
                                                store v2:word at ordinal+z*2
                                        else
                                                break
                                        end if
                                        z = z-x
                                end while
                                y = y+1
                        end while
                        x = x shr 1
                end while

                break
        end iterate
end macro

I'm going to add it into my Win32 headers for fasmg basic package.

Some notes about the conversion: where fasm 1 had FORWARD/REVERSE blocks I use a combination of REPEAT and INDX to iterate through the parameter values, and since this way everything is done within the first iteration of the outer ITERATE directive, I use the final BREAK to skip the next (unnecessary) iterations.

I updated the syntax of LOAD/STORE to the new one recommended for fasmg. I also had to put additional brackets in the expression with RVA, because this is not an internal operator and it is defined by PE formatting macros as a symbolic value "-PE.IMAGE_BASE+", so it no longer has precedence over minus sign like the RVA operator in fasm 1. Other than that, the export sorting code stayed as it was in fasm 1 version.
Post 19 Jan 2017, 20:26
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dunkaist



Joined: 31 Jul 2015
Posts: 11
Tomasz,
thank you for the quick and complete answer!

I'm keeping an eye on your 'compatibility' package, and this macro is just what I need. I learned a lot from your post.
Post 19 Jan 2017, 20:53
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