Print Page - how is it possible to handle the structs in 64 bits?

Title: how is it possible to handle the structs in 64 bits?
Post by: GUAN DE DIO on July 29, 2008, 10:01:04 PM

Hi everybody,

I'm doing my first experience in 64 bit platform and I have some doubt about the struct handling.

Fistly I tried to do something like this:

; wc is a variable type WNDCLASSEX

   lea rsi, wc
   assume rsi: ptr WNDCLASSEX
      mov [rsi].cbSize,sizeof WNDCLASSEX
   assume rsi:NOTHING

But this code does not compile.

Secondly I tried this

   lea rsi, wc
   mov dword ptr ds:[rsi],sizeof WNDCLASSEX

but doesn't work

What is the way to handle structs in 64 bits?

Best Regards,
GUAN

Title: Re: how is it possible to handle the structs in 64 bits?
Post by: MazeGen on July 30, 2008, 08:10:57 AM

This worked fine for me some months ago, when I was playing with Iczelion's tute 03:

Code Select


WinMain PROC FRAME ;hInst:HINSTANCE, hPrevInst:HINSTANCE, CmdLine:LPSTR, CmdShow:DWORD
;LOCAL  wc:WNDCLASSEX
;LOCAL  msg:MSG
;LOCAL  hwnd:HWND

 push   rbp
.PUSHREG rbp

 sub    rsp, 80t+32t+8+8
.ALLOCSTACK 80t+32t+8+8

 mov    rbp, rsp
.SETFRAME rbp, 0

.ENDPROLOG

 wc             EQU <(rbp+0).WNDCLASSEX>
 msg            EQU <(rbp+80t).MSG>
 hwnd           EQU <qword ptr (rbp+80t+32t)>

 CmdShow        EQU <dword ptr (rbp+80t+32t+8+8 +8+8+24t)>
 CmdLine        EQU <dword ptr (rbp+80t+32t+8+8 +8+8+16t)>
 hPrevInst      EQU <qword ptr (rbp+80t+32t+8+8 +8+8+8)>
 hInst          EQU <qword ptr (rbp+80t+32t+8+8 +8+8+0)>

 mov    [hInst], rcx
 mov    [hPrevInst], rdx
 mov    [CmdLine], r8d
 mov    [CmdShow], r9d

 mov    [wc].cbSize, SIZEOF WNDCLASSEX
 mov    [wc].style, CS_HREDRAW OR CS_VREDRAW
 lea    rax, [WndProc]
 mov    [wc].lpfnWndProc, rax
 mov    [wc].cbClsExtra, NULL
 mov    [wc].cbWndExtra, NULL
 mov    rax, [hInst]
 mov    [wc].hInstance, rax
 mov    [wc].hbrBackground, COLOR_WINDOW+1
 mov    [wc].lpszMenuName, NULL
 lea    rax, [ClassName]
 mov    [wc].lpszClassName, rax
 ...

Title: Re: how is it possible to handle the structs in 64 bits?
Post by: GUAN DE DIO on July 30, 2008, 02:50:48 PM

Hi MazeGen,

Thanks for your request, but I have one doubt about it.

In 32 bit a lot of time we have a pointer to one struct in some register, i.e in esi, for handling his struct we could make.

assume esi: ptr THE NAME OF THE STRUCT

....

assume esi:NOTHING

How can we do something like this in 64 bits?

The example that you give me declares the variables for handling, but if I gave the pointer in a register ?

Best Regards,
GUAN

Title: Re: how is it possible to handle the structs in 64 bits?
Post by: MazeGen on July 30, 2008, 03:35:03 PM

Yep, ASSUME doesn't seem to be supported in ML64.

You can use the longer notation though:

Code Select


 lea ebx, [wc]
 mov [ebx].WNDCLASSEX.cbSize, SIZEOF WNDCLASSEX

Title: Re: how is it possible to handle the structs in 64 bits?
Post by: GUAN DE DIO on July 30, 2008, 05:14:02 PM

OK thanks again

GUAN

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Project Support Forums => 64 Bit Assembler => Topic started by: GUAN DE DIO on July 29, 2008, 10:01:04 PM