From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31373 invoked by alias); 7 May 2002 22:13:35 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 31355 invoked from network); 7 May 2002 22:13:33 -0000 Received: from unknown (HELO localhost.redhat.com) (216.138.202.10) by sources.redhat.com with SMTP; 7 May 2002 22:13:33 -0000 Received: from cygnus.com (localhost [127.0.0.1]) by localhost.redhat.com (Postfix) with ESMTP id 14C963D2B; Tue, 7 May 2002 18:13:39 -0400 (EDT) Message-ID: <3CD85192.7020100@cygnus.com> Date: Tue, 07 May 2002 15:13:00 -0000 From: Andrew Cagney User-Agent: Mozilla/5.0 (X11; U; NetBSD macppc; en-US; rv:1.0rc1) Gecko/20020429 X-Accept-Language: en-us, en MIME-Version: 1.0 To: joern.rennecke@st.com Cc: aoliva@redhat.com, ezannoni@redhat.com, gcc@gcc.gnu.org, gdb@sources.redhat.com, bje@redhat.com Subject: Re: SH5 compact register numbering in gcc -> gdb interface References: <3CCED903.294513BE@st.com> <15568.36275.110744.510692@localhost.redhat.com> <3CD12BF8.7E1650C1@st.com> <3CD7EB51.7816DD1@st.com> <3CD803BC.5060900@cygnus.com> <3CD823D1.FC1E3717@st.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2002-05/txt/msg00065.txt.bz2 > ac131313@cygnus.com wrote: > >> Humor me here. >> >> How do you use dwarf2 cfi to unwind a compact register (saved on the >> stack) back to a media register? In addition to the address of the >> saved register you'll need to know that only part of the register was >> saved. Does CFI describe this? > > > With the proposed numbering change (2nd revision), we get different > numbers to describe compact an media registers. So when only the lower > 32 bits are saved, gcc can use the SHcompact register number to describe > this. Ok. > N.B., the upper 32 bits of the register are actually overwritten in the > process. The restore from the stack sign-extends from bit 31. The caller > is responsible to make sure that no 64 bit value is live in the register. This is the bit that I'm still missing. As far as I know dwarf2cfi doesn't have stuff to indicate ``sign-extend''. I guess this would still be handled by GDB magic? (this is what the existing sh5 code appears to do.) enjoy, Andrew