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pinny_woman



Joined: 29 Mar 2008
Posts: 9
pinny_woman
Hi,

I've been trying to convert an app written in C to assembly. I've managed well so far with the conversion but have come unstuck with the following:

there's a procedure declared thus:
Code:
HBITMAP CreateMask(HBITMAP hColor, COLORREF crTrans)
    

which I converted to:
Code:
proc CreateMask, hColor, crTrans
.
.
endp
    


The problem I'm having is how to pass the params.
The C code is:
Code:
gMask = CreateMask(gImg, RGB(0, 0, 0));
    


How do I convert the RGB(0,0,0) to pass in asm?

Thanks for your time Wink
Post 30 Mar 2008, 17:05
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DJ Mauretto



Joined: 14 Mar 2007
Posts: 464
Location: Rome,Italy
DJ Mauretto
Code:
      push    0              ; RGB = 0,0,0  Question  
 push    gImg 
       call    CreateMask


If you Have RGB struct in bytes 

  movzx   eax,byte [Red] 
     shl     eax,16 
     movzx   ebx,byte [Green]  
  shl     ebx,8 
      or      eax,ebx 
    movzx   ecx,byte [Blu] 
     or      eax,ecx 
    push    eax                  ; EAX = 0x00RRGGBB
     push    gImg 
       call    CreateMask
    
Post 30 Mar 2008, 18:13
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itsnobody



Joined: 01 Feb 2008
Posts: 93
Location: Silver Spring, MD
itsnobody
Just use 0x00RRGGBB instead of the RGB macro
Post 30 Mar 2008, 18:34
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edfed



Joined: 20 Feb 2006
Posts: 4242
Location: 2018
edfed
Code:
movzx eax,[green]
mov ah,[red]
shl eax,8
mov al,[blue]
push eax
push gimg
call createmask
    

7 lines instead of 10.

are rgb encoded on bytes or dwords?
cause C convention is to pass params by the stack.
then, you build some equates to access them via the esp or ebp pointer.
Post 30 Mar 2008, 20:20
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