Date: Tue, 02 Mar 1999 15:31:15 -0800 From: Thomas Stephens <tas@stephens.org> To: John Polstra <jdp@polstra.com> Cc: hackers@freebsd.org, Thomas Stephens <tas@stephens.org> Subject: Re: ELF, System V and multiple ABIs Message-ID: <199903022331.XAA04972@stephens.ml.org> In-Reply-To: Your message of "Sat, 27 Feb 1999 11:05:56 PST." <199902271905.LAA10250@vashon.polstra.com>
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John Polstra wrote: >In article <199902171844.SAA24903@stephens.ml.org>, >Thomas Stephens <tas@stephens.org> wrote: > >> I was looking over the latest System V ABI draft, and noticed there is >> an update (dated April 1998) which includes modifications to the ELF >> format. Significantly, the usage of the e_ident array in the ElfXX_Ehdr >> structure has changed slightly, in order to allow for multiple ABIs on >> each hardware platform. >> >> While the ELF format defined in the previous draft only used the first >> seven bytes of e_ident, with byte eight (EI_PAD) representing the start >> of padding, the current one adds two new values to support an OS/ABI >> identifier number followed by a version. As a side-effect, EI_PAD has >> been redefined: >> >> EI_OSABI 7 (OS/ABI identifier) >> EI_ABIVERSION 8 (OS/ABI version) >> EI_PAD 9 >> >> This new version of ELF currently defines EI_OSABI values for System V, >> HP-UX and stand-alone (embedded) applications, but it seems to me it >> would make things much easier if all ELF-compatible systems were to >> adopt it. > >Thanks very much for pointing this out! I wasn't aware of it. Glad to be of help! >I think it would be great to adopt this, and it looks like we could do >it without breaking backward compatibility for our current "branding" >scheme. Ah, that's good. I had noticed there was some overlap with EI_BRAND, but am new to FreeBSD and hadn't really looked at `branding' in depth. >Today I have written to a contact at SCO to try to get an OS/ABI code >assigned to FreeBSD. Hopefully that will bear some fruit and we can >move on to this scheme. That sounds great! If the other BSDs, Linux, Sun, etc. can be persuaded to adopt the new ELF spec as well, this whole problem of competing ABIs might finally be resolved. Thomas Stephens tas@stephens.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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