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From: Brandon Chase <tapedispenser7 AT hotmail DOT com>
To: <cygwin AT cygwin DOT com>
Subject: Re: Assembly language exit() syscall does not return correct value
Date: Tue, 16 Mar 2010 16:45:03 +0000
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On 15/03/2010 16:56, Christopher Faylor wrote:
> On Mon, Mar 15, 2010 at 04:23:39PM +0000, Brandon Chase wrote:
>> The following program is supposed to return a value of 222 when echo $?=
=20
>> run, but I get 127 every time, no matter what I change. I have looked=20
>> around but cannot seem to find out if this is an error or a=20
>> cygwin-specific value.

> # %ebx is the status code for the exit system call
> # and it already has the maximum number
> 	movl $1, %eax			#1 is the exit() syscall
>=20
> If, in theory, I got this right then, on linux it SEGVs.  I would
> not expect anything different on Cygwin.  It seems like you need
> to actually call exit() if you want this to exit.

  Yeah, this looks like it was Linux assembly code and the "int 0x80" has j=
ust
been removed.  What you said.  Also, it should probably define '_main' rath=
er
than '_start'.  And use the gcc driver to assemble and link it so as to get
the necessary startup code.

  Brandon, Cygwin isn't compatible with Linux at the assembler-code level, =
in
particular Cygwin isn't a real kernel, so it doesn't have a syscall interfa=
ce;
you just call system functions as if they were ordinary functions.

    cheers,
      DaveK



So I cannot compile assembly language with Cygwin? Do I need a linux shell?





=20=09=09=20=09=20=20=20=09=09=20=20
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