Strange behaviour in assembly language program

[Daniela]

Hi!

I'm already a bit experienced with assembly, and started to enter my 
executables directly in the hexeditor (for educational purpose only; I know 
this is poor programming style).
I do not yet fully understand all aspects of the ELF header, but I managed to 
somehow write working ELF executables. I tried first a program that exits 
with status 1, and it works. But then I tried other values, and found out 
that it always exits with 1 no matter what I enter. I don't think I made a 
stupid mistake, because the Linux version (exit value given in EBX and 
ELF_OSABI = 03) runs perfectly in emulation mode. The first strange thing is, 
that it doesn't run on a real Linux system (tells me it doesn't have enough 
core memory for a 96 byte program).

Second strange thing:
Finally I came up with the simplest ASM program that reproduces the error.
Here it is:

.text
.global _start
_start:
	pushl	$0
	movl	$1, %eax
	int	$0x80

I looked everywhere (Developer's handbook, Google, ...) to find the solution, 
but all resources I consulted tell me this is the right way to do it.
This program, however, always exits with 1 regardless of the value I push.

Please, can someone tell me that I made a really stupid error? I'm already 
pulling my hair out.

Thanks for your time.

Daniela