From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <cgen-return-1233-listarch-cgen=sources.redhat.com@sources.redhat.com>
Received: (qmail 20696 invoked by alias); 24 Dec 2002 17:53:14 -0000
Mailing-List: contact cgen-help@sources.redhat.com; run by ezmlm
Precedence: bulk
List-Subscribe: <mailto:cgen-subscribe@sources.redhat.com>
List-Archive: <http://sources.redhat.com/ml/cgen/>
List-Post: <mailto:cgen@sources.redhat.com>
List-Help: <mailto:cgen-help@sources.redhat.com>, <http://sources.redhat.com/lists.html#faqs>
Sender: cgen-owner@sources.redhat.com
Received: (qmail 20689 invoked from network); 24 Dec 2002 17:53:13 -0000
Received: from unknown (HELO mx1.redhat.com) (66.187.233.31)
  by 209.249.29.67 with SMTP; 24 Dec 2002 17:53:13 -0000
Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254])
	by mx1.redhat.com (8.11.6/8.11.6) with ESMTP id gBOHQLB03540
	for <cgen@sources.redhat.com>; Tue, 24 Dec 2002 12:26:21 -0500
Received: from post-office.corp.redhat.com (post-office.corp.redhat.com [172.16.52.227])
	by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id gBOHr1a29049;
	Tue, 24 Dec 2002 12:53:01 -0500
Received: from greed.delorie.com (dj.cipe.redhat.com [10.0.0.222])
	by post-office.corp.redhat.com (8.11.6/8.11.6) with ESMTP id gBOHr0K31722;
	Tue, 24 Dec 2002 12:53:00 -0500
Received: (from dj@localhost)
	by greed.delorie.com (8.11.6/8.11.6) id gBOHqxJ28997;
	Tue, 24 Dec 2002 12:52:59 -0500
Date: Tue, 24 Dec 2002 09:53:00 -0000
Message-Id: <200212241752.gBOHqxJ28997@greed.delorie.com>
From: DJ Delorie <dj@redhat.com>
To: dje@sebabeach.org
CC: geoffk@geoffk.com, cgen@sources.redhat.com
In-reply-to: <20021224055735.2F216B539@seba.sebabeach.org> (message from Doug
	Evans on Mon, 23 Dec 2002 21:57:35 -0800 (PST))
Subject: Re: opcode bits beyond base-insn-bitsize
References:  <20021224055735.2F216B539@seba.sebabeach.org>
X-SW-Source: 2002-q4/txt/msg00125.txt.bz2


> Can anyone remember what the details are?
> i.e. what didn't work?  assembler? disassembler? simulator?

xstormy16 has both 16bit and 32bit opcodes, and some of the 32bit
opcodes have decodable bits in the second half.  The base-insn-bitsize
is used to set up the masks and such, so it needs to be at least as
big as the largest decodable bits.

The tricky bit is when the 32-bit opcodes are mixed endian (i.e.  the
first 16 bits are swapped independently of the second 16 bits,
resulting in ABCD or BADC endian, but not DCBA).