2009-09-04 FreeBSD assembler open file

Here code for opening file, reading from it and close it. At beginig i have thinked taht it will be complicated. But it was easy and interesting as C. Here is both C and asm code.
openfile.asm

;/usr/include/sys/syscall.h
;#define SYS_read        3
;#define SYS_write       4
;#define SYS_open        5
;#define SYS_close       6

sys_read equ 3
sys_write equ 4
sys_open equ 5
sys_close equ 6
o_rdonly equ 0

format ELF
section '.text' executable
public _start
_start:
    ;int fid = open("file.txt",O_RDONLY);
    push o_rdonly
    push f
    mov  eax, sys_open 
    push eax
    int  0x80
    add  esp, 4*3   ; clear stack after interupt	
    mov dword [f_id], eax
	
    ;read( fid , &buf[0] , 12 );
    push f_buf_len
    push f_buf
    push eax
    mov eax, sys_read
    push eax
    int 0x80
    add esp, 4*4
	
    ;write( 1 , &buf[0] , 12 );
    push f_buf_len   
    push f_buf     
    push 1         
    mov  eax, sys_write     
    push eax
    int  0x80
    add  esp,4*3

    ;close( fid );
    push dword [f_id]
    mov eax, sys_close
    push eax
    int 0x80
    add esp, 4*2
	
    ;exit from programm
    xor eax, eax	;eax = 0
    push eax
    inc eax			;eax = 1, sys_exit
    int 80h			;system interupt

section '.data' writeable
	f db "file.txt",0
	f_len = $-f
	f_buf db 12 dup 0
	f_buf_len = $-f_buf
	f_id dd 0

fasm openfile.asm openfile.o
ld openfile.o -o openfile

c.c

#include <fcntl.h>

int main()
{
	int fid = open("file.txt",O_RDONLY);
	char buf[12];
	read( fid , &buf[0] , 12 );
	write( 1 , &buf[0] , 12 );
	close( fid );
	return 0;
}

gcc c.c -o c

file.txt
Only text!!!