ASM Community

Hi guys,

i have a code that i would like to replace with another instruction and produces the same effect.

The beginning of the function is:

dis                 DRAWITEMSTRUCT    <?>

(....)

Function proc uses edi esi ecx, param:DWORD

        

    mov esi, param

    lea edi, dis

    mov ecx, sizeof dis

    rep movsb    

I?m trying to replace the rep movsb instruction with another one....but it is not working

I tried to replace the rep movsb with

mov edi, dword ptr

but it is not working.


And then i replaced with

push esi
add esi, ecx
pop esi

And it didn?t worked either

What is the replacement for the rep movsb instruction ?

Best Regards,

Guga

You mean you want this?

  mov esi, param

  lea edi, dis

  mov ecx, sizeof dis

  mov edi, dword ptr [dis+sizeof dis]

That's really weird. Why would you set EDI, and then set it again before using the first value?

Are you trying to do the ASM equivalent to this:

DRAWITEMSTRUCT dis;

void copystruct ( DRAWITEMSTRUCT * param ) {

    dis = *param;

}

There is no other single instruction that can copy any arbitrarily sized data. If you replace "rep movsb" with that "mov edi", you'll notice that there is no longer anything that actually writes to "dis".

If the DRAWITEMSTRUCT is 1, 2 or 4 bytes, you can move the whole structure into a register and then copy the register to the new location. If the DRAWITEMSTRUCT is a multiple of 2 bytes, you can use the "rep movsw" instruction (don't forget to divide ecx by 2). If DRAWITEMSTRUCT is a multiple of 4 bytes, you can use "rep movsd".

What you can do is make a macro that can copy a fixed size of data from one location to another, choosing between using registers, rep movsb, rep movsw, rep movsd, or some combination, depending on the length of the data. Remember that you can combine movsb, movsw, and movsd to copy any size of data as fast as possible. For example, if you want to copy 255 bytes, you can do:

   mov     ecx, 255 / 4

   rep     movsd

   movsw

   movsb

I?m trying to make a Editbox display text in different collours using a parser that is able to convert the colors, without using RichEdit controls or libraries.

The close i got was this file.


But i?m still stuck on te coding...

Best Regards,

Guga

Hi Lennon

What i don?t want is use richedit....For exmaple, if i have a richedit doc with 500 Kb...only the text has no more then 20 Kb, and using the parser tokesn, it wil be no mroe then 30 Kb.

What?s i?m trying to reroduce is nemo?s code for an editbox.

So, the basics of an richedit can have the same result as his code on a editbox.
Guga