From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from agrxsusmail.smiths.aero (host241-chi.smiths-group.com [65.216.75.241]) by ozlabs.org (Postfix) with ESMTP id 3057A67A3A for ; Thu, 27 Jul 2006 22:36:07 +1000 (EST) Message-ID: <44C8B330.7030600@smiths-aerospace.com> Date: Thu, 27 Jul 2006 08:36:00 -0400 From: Jerry Van Baren MIME-Version: 1.0 To: "Patrick J. Kelsey" Subject: Re: Can 750 user-mode binaries run on a 603e core? References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Patrick J. Kelsey wrote: > (sorry about that last one. had a bit of trouble with a certain web based mail client...) > > Thanks for the reply, Kumar. > > That sounds encouraging. One of the things I was worried about with > scheduling differences would be a differing number of branch delay > slots between the two core versions. I'm still a bit new to the > details of the PowerPC architecture, and at this point I'm not even > sure if there are branch delay slots, although it does seem from my > reading that the 603e and 750 pipelines are the same, in which case > there would ceratinly be no worries here. FWIIW, the PowerPC architecture has hardware instruction interlocking and scheduling and doesn't require the compiler to implement the branch delay slots like, for instance, the MIPS architecture. This is much more compiler and portability friendly, but at the expense of more logic in the processor (the PowerPC is not nearly as minimalistic as the MIPS). > At this point, I'm not concerned so much about an inefficient > schedule resulting from running -mcpu=750 code on a 603e as long as > the execution is correct. > > Pat gvb