Date: Sat, 14 Nov 1998 19:15:56 +0200 From: Ruslan Ermilov <ru@ucb.crimea.ua> To: Robert Nordier <rnordier@nordier.com> Cc: FreeBSD Hackers <hackers@FreeBSD.ORG> Subject: Re: FreeBSD on i386 memory model Message-ID: <19981114191556.A17660@ucb.crimea.ua> In-Reply-To: <199811131930.VAA12575@ceia.nordier.com>; from Robert Nordier on Fri, Nov 13, 1998 at 09:30:44PM %2B0200 References: <19981113202027.A15520@ucb.crimea.ua> <199811131930.VAA12575@ceia.nordier.com>
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On Fri, Nov 13, 1998 at 09:30:44PM +0200, Robert Nordier wrote:
> Ruslan Ermilov wrote:
> > Hi!
> >
> > I would like to practice in writing assembler programs
> > under FreeBSD.
> >
> > Is there any doc/book/man which describes the FreeBSD
> > memory model on i386 architecture?
>
> Essentially it's just a flat protected model, and for most purposes
> can simply be ignored. Rather than documentation, I'd suggest
What documentation do you mean?
> looking at C startup code (src/lib/csu), i386-specific C library
> functions (src/lib/libc/i386), and at the output of `cc -S'.
>
> FWIW, here's a small standalone i386 assembler program:
>
> main: call .+0x5
> popl %ebp
> subl $0x5,%ebp
> pushl $msg.1-msg
> leal msg-main(%ebp),%eax
> pushl %eax
> pushl $0x1
> movl $0x4,%eax
> call .+0x5 <-- why this one?
> lcall $0x7,$0x0
> pushl $0x0
> movl $0x1,%eax
> call .+0x5 <-- and this one?
> lcall $0x7,$0x0
> msg: .ascii "hello, world!\n"
> msg.1:
Unfortunately, I can't compile it, as(1) gives the following:
{standard input}: Assembler messages:
{standard input}:5: Error: Unimplemented segment type 0 in parse_operand
{standard input}:10: Error: operands given don't match any known 386 instruction
{standard input}:14: Error: operands given don't match any known 386 instruction
It seems that as(1) doesn't understand ``lcall $SECTION, $OFFSET''.
At least on my 2.2.1, 2.2.5 and 2.2.7+ machines:
FreeBSD relay.ucb.crimea.ua 2.2.7-STABLE FreeBSD 2.2.7-STABLE #0: Sun Oct 4 18:08:06 EEST 1998 root@:/usr/src/sys/compile/CHYRO i386
GNU assembler version 1.92.3, FreeBSD $Revision: 1.4 $
Any ideas?
--
Ruslan Ermilov Sysadmin and DBA of the
ru@ucb.crimea.ua United Commercial Bank
+380.652.247.647 Simferopol, Ukraine
http://www.FreeBSD.org The Power To Serve
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