Win32 function call using GNU assembler

Win32 function call using GNU assembler

[uglyhunK]

Hi,

The following assembly source is not working. Really not sure where I'm going wrong.
Any guidance will be appreciated.

.section .data
	CLASS_NAME:
		.ascii "M\0a\0i\0n\0\0\0" # Main
	WINDOW_NAME:
		.ascii "A\0S\0M\0 \0W\0i\0n\0d\0o\0w\0\0\0" # ASM Window
		
.section .text
	.globl _WinMain@16
	_WinMain@16:
		# function prologue
		pushl	%ebp
		movl	%esp, %ebp
		
		pushl	$0				# LPVOID lpParam
		movl	8(%ebp), %eax
		pushl	%eax			# HINSTANCE hInstance
		pushl	$0				# HMENU hMenu
		pushl	$0				# HWND hWndParent
		pushl	$120			# nHeight
		pushl	$240			# nWidth
		pushl	$-2147483648	# y
		pushl	$-2147483648	# x
		pushl	$13565952		# dwStyle
		pushl	$WINDOW_NAME	# lpWindowName
		pushl	$CLASS_NAME		# lpClassName
		pushl	$512			# dwExStyle
		call	_CreateWindowExA@48
		add		$48, %esp
		
		# function epilogue
		movl	%ebp, %esp
		popl	%ebp
		ret

Thank you

Re: Win32 function call using GNU assembler

[Robert Plantz]

What do you mean by "not working"? What is the behavior?

I do note that the
          add $48, %esp
instruction is irrelevant since it is immediately followed by
          movl %ebp, %esp

BTW, I'm not a Win32 programmer, so I don't know if I can add any
further insight.

-- Bob

On Wed, 2009-09-02 at 13:41 +0530, uglyhunK wrote:
> Hi,
> 
> The following assembly source is not working. Really not sure where I'm going wrong.
> Any guidance will be appreciated.
> 
> .section .data
> 	CLASS_NAME:
> 		.ascii "M\0a\0i\0n\0\0\0" # Main
> 	WINDOW_NAME:
> 		.ascii "A\0S\0M\0 \0W\0i\0n\0d\0o\0w\0\0\0" # ASM Window
> 		
> .section .text
> 	.globl _WinMain@16
> 	_WinMain@16:
> 		# function prologue
> 		pushl	%ebp
> 		movl	%esp, %ebp
> 		
> 		pushl	$0				# LPVOID lpParam
> 		movl	8(%ebp), %eax
> 		pushl	%eax			# HINSTANCE hInstance
> 		pushl	$0				# HMENU hMenu
> 		pushl	$0				# HWND hWndParent
> 		pushl	$120			# nHeight
> 		pushl	$240			# nWidth
> 		pushl	$-2147483648	# y
> 		pushl	$-2147483648	# x
> 		pushl	$13565952		# dwStyle
> 		pushl	$WINDOW_NAME	# lpWindowName
> 		pushl	$CLASS_NAME		# lpClassName
> 		pushl	$512			# dwExStyle
> 		call	_CreateWindowExA@48
> 		add		$48, %esp
> 		
> 		# function epilogue
> 		movl	%ebp, %esp
> 		popl	%ebp
> 		ret
> 
> Thank you--
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Re: Win32 function call using GNU assembler

[Brian Raiter]

> The following assembly source is not working. Really not sure where
> I'm going wrong.

Well, you're posting a windows programming question to a list called
linux-assembly. So that's the first thing I'd say that you're doing
wrong.

But, marshalling my vestigial Windows programming knowledge, it looks
like you're defining a WinMain function that calls CreateWindowEx and
then immediately exits, thus destroying the window well before it has
a chance to display itself. So that's your central problem.

b