From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.10.13) id 19GPHp-0000pm-00 for qemu-devel@nongnu.org; Thu, 15 May 2003 16:25:09 -0400 Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.10.13) id 19GPHa-0000Hb-00 for qemu-devel@nongnu.org; Thu, 15 May 2003 16:24:54 -0400 Received: from pizda.ninka.net ([216.101.162.242]) by monty-python.gnu.org with esmtp (Exim 4.10.13) id 19GPHI-0007sJ-00 for qemu-devel@nongnu.org; Thu, 15 May 2003 16:24:37 -0400 Date: Thu, 15 May 2003 13:24:06 -0700 (PDT) Message-Id: <20030515.132406.115929721.davem@redhat.com> Subject: Re: [Qemu-devel] [PATCH] Updated Sparc support From: "David S. Miller" In-Reply-To: <20030515201724.GA19302@bushwacker> References: <20030515.130541.41655467.davem@redhat.com> <20030515201724.GA19302@bushwacker> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: List-Help: List-Post: List-Subscribe: , List-Archive: List-Unsubscribe: , To: jrydberg@night.trouble.net Cc: qemu-devel@nongnu.org From: Johan Rydberg Date: Thu, 15 May 2003 22:17:24 +0200 Using global registers for commonly used variables such as the CPU structure and current virtual program counter will increase the performance with a magnitude I guess. So, if I understand you correctly, everything should work pretty good i you use -fflat and stay away from the input registers? (I have no need for the -fno-delay-slot flag) -mflat SUCKS, it generates the worst code possible. Also, if you're going to use global register, be forewarned that if you call into libc you risk them being clobbered. Sparc-linux libc clobbers just about every global register in some piece of assembly somewhere. There are also very strict rules about which global register an application can use in this fashion. Please refer to the standards documents about exactly which these are (they are different for 32-bit and 64-bit sparc) and no I don't have time to discuss this further nor point you at where to get these documents.:-)