From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51587) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WDGv0-00079z-Ql for qemu-devel@nongnu.org; Tue, 11 Feb 2014 12:14:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WDGuu-0002ur-UT for qemu-devel@nongnu.org; Tue, 11 Feb 2014 12:14:46 -0500 Message-ID: <52FA5A65.5080004@gmail.com> Date: Tue, 11 Feb 2014 11:14:13 -0600 From: Tom Musta MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] PowerPC Decimal Floating Point List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: QEMU Developers , "qemu-ppc@nongnu.org" QEMU is currently lacking support for the Decimal Floating Point category of instructions (see Power ISA V2.07 Chapter 6). I intend to add this support. Has this topic been investigated before and if so can anyone point me to that discussion? A Google search came up empty for me. My proposal is to incorporate the libdecnumber component of libdfp (http://www.eglibc.org/cgi-bin/viewvc.cgi/libdfp/trunk/) in a manner analogous to how softfloat is used for binary floating point. So, for example, the helper for the dadd instruction would look something like the following: - map FPSCR state to a decContext. - convert the contents of the source FPRs to decNumbers (decimal64ToNumber). - call decNumberAdd - convert the resultant decNumber to DPD (decimal64FromNumber) - update FPSCR per the decContext.status and result. Comments?