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From: Jody <jbruchon@nc.rr.com>
To: ELKS <linux-8086@vger.kernel.org>
Subject: Re: Ping!
Date: Tue, 06 Jun 2006 00:44:27 -0400	[thread overview]
Message-ID: <4485082B.7040702@nc.rr.com> (raw)
In-Reply-To: <792c60620606051930k776e61e8m4ca6ef99f8707b09@mail.gmail.com>

Here's a short answer.

gcc = 32- or 64-bit code compiler, end of story.  Doesn't do 8- or 
16-bit code at all.  Doesn't handle segmented architecture too well, 
from what I understand.  8086/88 = 16-bit segmented architecture with no 
mode of "flat" addressing or limitless segment size.  Big problem.

bcc = 16-bit capable compiler taken from the Minix system, designed with 
the 16-bit real-mode 8086 in mind, handles the ugly intricate details 
that gcc can smile and avoid due to the use of flat protected mode 
memory blahblahblah.

Assembly is likely used to optimize certain functions or to ensure that 
the function behaves correctly independent of changes in bcc and the 
8086 libc.  ELKS is not intended to be portable across CPUs at all; only 
8086 CPUs are targeted, with 80286 protected-mode code that doesn't (and 
likely will never) work fully.  Linux itself started with a lot of asm 
in the code, and as it grew like a virus in popularity, the 
arch-specific asm chunks were moved around so that new architectures 
could be ported to with more ease.  ELKS isn't that popular, thus size 
and speed optimized assembly routines are totally acceptable, especially 
since we're constantly hitting those damned segment limits already.

That's my take, but I'm not a C programmer.  Also, don't send mail to 
list subscribers if you send it to the ELKS list, because duplicate 
messages are a big irritant of mine.  Keep in mind that we get the list, 
and thus we're already getting one copy.

Jody


Vikas Kumar wrote:
> I had a question. What is the advantage of using bcc over gcc. Why is
> bcc being used in some parts of the code vs gcc in other parts of the
> code. A large part of the code where bcc is used to compile uses a lot
> of assembly, rather than C. Why was it written this way ? Any pointers
> ?
> 
> Vikas
> 
> On 6/5/06, Jody <jbruchon@nc.rr.com> wrote:
> 
>> Has anyone been doing any programming on ELKS as of late?
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  reply	other threads:[~2006-06-06  4:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-05 16:16 Ping! Jody
2006-06-06  2:30 ` Ping! Vikas Kumar
2006-06-06  4:44   ` Jody [this message]
2006-06-06  9:33   ` Ping! Alan Cox

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