ASM Community

I have come upon a weird problem with call wsprintf with invoke. Perhaps I'm only doing something wrong here, but when I use a WORD for argument in wsprintf,
and use invoke,
the compiler produce code like this to push the value:

push 0

push word ptr TheNumber

And push 0 is the opcode 6a00 which pushes a DWORD, 00000000.
So the whole program crash, because the stackpointer gets messed up and wsprintf fails somehow.

=(((((((

It should be like this to work,

push word ptr 0

push word ptr TheNumber

I did a testprogram, please check it, and correct if I'm wrong,
because I really need to push words and use invoke, I don't want to handcode the calls to wsprintf.

Am I doing something wrong in the invoke? Hope I'm not doing something terribly wrong...

.486

.model flat,stdcall

option casemap:none



include \masm32\include\windows.inc

include \masm32\include\kernel32.inc

include \masm32\include\user32.inc



includelib \masm32\lib\kernel32.lib

includelib \masm32\lib\user32.lib



.data



szMes db "Number1:%#X",13,10,"The_String:%s",13,10,"Number2:%#X",0



number1 dw 505h

The_String db "Hello there.",0

number2 dw 0FFFFh





szCaption db "testing wsprintf",0



.data?



szBuffer db 256 dup (?)



.code



start:



; This will produce right result



    push word ptr 0

    push number2

    push OFFSET The_String

    push word ptr 0

    push number1

    push OFFSET szMes

    push OFFSET szBuffer

    

    call wsprintf

    add esp,4*5

    invoke MessageBoxA, NULL, addr szBuffer, addr szCaption, MB_OK



; This will produce wrong result, and crash the program



    invoke wsprintf, addr szBuffer, addr szMes, number1, addr The_String, number2

    

    invoke MessageBoxA, NULL,addr szBuffer,addr szCaption,MB_OK



invoke ExitProcess,0



end start

Yes I just saw it when posting , I corrected that typo, it makes no difference though.
The problem still remains as I described it above.

What about changing word to dword, that should fix the problem?

However i do not know why there is a need to push 0 or rather push word ptr 0

[size=9].486

.model flat,stdcall

option casemap:none



include \dev\masm32\include\windows.inc

include \dev\masm32\include\kernel32.inc

include \dev\masm32\include\user32.inc



includelib \dev\masm32\lib\kernel32.lib

includelib \dev\masm32\lib\user32.lib



.data



szMes db "Number1:%#X",13,10,"The_String:%s",13,10,"Number2:%#X",0



number1 dw 505h

[color=blue]db 0, 0  ;or simply dw 0[/color]

The_String db "Hello there.",0

number2 dw 0FFFFh

[color=blue]db 0, 0  ;or simply dw 0[/color]

[color=red]number3 dw 999h  ;Added, to test if it reads this address.[/color]







szCaption db "testing wsprintf",0



.data?



szBuffer db 256 dup (?)



.code



start:



; This will produce right result



    push word ptr 0

    push number2

    push OFFSET The_String

    push word ptr 0

    push number1

    push OFFSET szMes

    push OFFSET szBuffer



    call wsprintf

    add esp,4*5

    invoke MessageBoxA, NULL, addr szBuffer, addr szCaption, MB_OK



; This will produce right result



    invoke wsprintf, addr szBuffer, addr szMes, [color=blue]DWORD PTR [number1][/color], addr The_String, [color=blue]DWORD PTR [number2][/color]



    invoke MessageBoxA, NULL,addr szBuffer,addr szCaption,MB_OK



invoke ExitProcess,0



end start[/size]

Remember normal stack alignment is 4.