Re: [Nasm-users] can't write argv[0] on stdout

[H. P. A. <hp...@zy...>]

On 08/18/2009 07:34 AM, Holger Hanrath wrote:
> Hi all,
> 
> i want to write 3 bytes of argv[0] on stdout but it doesn't work. 
> Return code -14 (EFAULT Bad address). Am i missing something here? 
> 
> System is archlinux 2009.08 x86_64 kernel 2.6.31-rc6 
> nasm 2.05.01 Binutils 2.19.1.20090418
> 
> 
> 
> stdout	equ	1
> write	equ	4
> exit	equ	1
> 
> section .text
> 	global	_start
> _start:	
> 	pop	rax		; rax = argc
> 	pop	rax		; rax = argv[0]
> 
> 	mov	rdx,	3	; write 3 bytes
> 	mov	rcx,	rax	; rcx = rax = argv[0]
> 	mov	rbx,	stdout	
> 	mov	rax,	write	
> 	int	0x80
> 	
> 	mov	rbx,	0
> 	mov	rax,	exit
> 	int	0x80
> 

int 0x80 is used for 32-bit system calls.  64 bits uses syscall, and
entirely different system call numbers and a different calling convention.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.