From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Andy Wingo Newsgroups: gmane.lisp.guile.devel Subject: Re: redoing SCM representation in 2.2 Date: Sun, 15 May 2011 17:47:09 +0200 Message-ID: References: <2932B3D9-7CE6-46B9-8A1E-51702E417D53@raeburn.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: dough.gmane.org 1305474449 22280 80.91.229.12 (15 May 2011 15:47:29 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sun, 15 May 2011 15:47:29 +0000 (UTC) Cc: guile-devel To: Ken Raeburn Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Sun May 15 17:47:23 2011 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1QLdXN-0000ci-QA for guile-devel@m.gmane.org; Sun, 15 May 2011 17:47:22 +0200 Original-Received: from localhost ([::1]:56478 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QLdXN-0007Cs-4d for guile-devel@m.gmane.org; Sun, 15 May 2011 11:47:21 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:46514) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QLdXJ-0007Cc-TG for guile-devel@gnu.org; Sun, 15 May 2011 11:47:18 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QLdXI-0007GS-Bj for guile-devel@gnu.org; Sun, 15 May 2011 11:47:17 -0400 Original-Received: from a-pb-sasl-sd.pobox.com ([64.74.157.62]:60887 helo=sasl.smtp.pobox.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QLdXI-0007GO-7u for guile-devel@gnu.org; Sun, 15 May 2011 11:47:16 -0400 Original-Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by a-pb-sasl-sd.pobox.com (Postfix) with ESMTP id 832F24B35; Sun, 15 May 2011 11:49:21 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type:content-transfer-encoding; s=sasl; bh=37szUUQBX574 iyniZ4TFqeF6sq8=; b=VilwSRetwM8NMXi0NgpdXvz0O6SoV7jqUGyBXQcqQZUf r4M6VrEE1gNwk8lZA7mEape8FDivHg+3aC1yoNQvJWa3o92ST1Hl+HBzpsDQeRsV VlNcbeWOrDwxr4u7dUmR30A7Pev+BAaLIwEFUM67G2nPcADFKppYBQKmno+OdGU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type:content-transfer-encoding; q=dns; s=sasl; b=C797Pv u8jk/K1TOwTQRsC2DE8DCjUBLop3cknrvBbJJ0ua6Ts8fceXLkE+WETZERBtZI8/ 8Ni2ZX8dWs8rjEj25/wErDj04GqoMo/gljJSdA8Jl3gDvUklDxHgq8M6iv/90YDt 4XPrVbTYxIZK7zpRf0tNufiIOtav9IZcW5MIA= Original-Received: from a-pb-sasl-sd.pobox.com (unknown [127.0.0.1]) by a-pb-sasl-sd.pobox.com (Postfix) with ESMTP id 6FB564B34; Sun, 15 May 2011 11:49:20 -0400 (EDT) Original-Received: from unquote.localdomain (unknown [90.164.198.39]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by a-pb-sasl-sd.pobox.com (Postfix) with ESMTPSA id B08934B33; Sun, 15 May 2011 11:49:18 -0400 (EDT) In-Reply-To: <2932B3D9-7CE6-46B9-8A1E-51702E417D53@raeburn.org> (Ken Raeburn's message of "Sun, 15 May 2011 05:00:07 -0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) X-Pobox-Relay-ID: E5D97500-7F0A-11E0-A7BD-BBB7F5B2FB1A-02397024!a-pb-sasl-sd.pobox.com X-detected-operating-system: by eggs.gnu.org: Solaris 10 (beta) X-Received-From: 64.74.157.62 X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:12496 Archived-At: On Sun 15 May 2011 11:00, Ken Raeburn writes: > So... Guile 2.2 won't work on the VAXstation in my basement, which > doesn't do IEEE math? :-( > (Not that I've powered it up in some time...) I have no idea. However... note that GCC obsoleted all vax ports but openbsd and netbsd in 4.3, removed them in 4.4, and just obsoleted it on netbsd recently I think. Just saying :) > Guess I hadn't thought about that before; we've got code that refers to > IEEE floating point already, so does that mean we require IEEE floating > point already? Probably? I hope so? :) I think I'm too young to know about pre-ieee FP :) > On 64-bit SPARC and perhaps some other architectures, we'd be dependent > on the OS only effectively using 48 bits worth of address space even if > the hardware supports more. I'd be surprised if we encounter a program > that needs more storage than that, and I expect most current OSes will > tend to have a couple of regions growing toward each other rather than > scatter stuff all over the address space, but I could imagine a > particularly na=C3=AFve or aggressive form of address space layout > randomization trying to take advantage of all 64 bits by scattering > mapped memory throughout all 2**64 addresses (minus whatever the kernel > uses), for libraries or heap allocation or both. Yes, indeed. > If the 64-bit SCM type isn't required to represent the full range of > integer values the machine can support as immediate values, does it > really have to encompass the full range of "double" values? No, but the nice thing about doubles is that it's a closed set. Any operation on a double produces a double. Subsets do not have that property. >> I think we need to do the JSC way, as it appears to be the only way to >> work with the BDW GC, currently anyway. We will need some integration >> with the GC to ensure the 48-bit space, but that should be doable. > > Don't we have some objects now which can be initialized statically by > the compiler, and for which the addresses get encoded directly into the > resulting SCM objects? Yes, though this is optional. We could whitelist some set of platforms for which this can work. FWIW I plan on moving objcode to be ELF in 2.2, which will mean we write our own loader for ELF, so we would have similar concerns about mapping the file in the right address range. Regards, Andy --=20 http://wingolog.org/