From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Mimms To: LiuTao , "linuxppc-embedded@lists.linuxppc.org" Subject: Re: What does KERNELBASE mean? Date: Tue, 4 Jan 2000 21:07:45 -0800 Content-Type: text/plain References: <3872CF70.45BCE11C@ict.ac.cn> In-Reply-To: <3872CF70.45BCE11C@ict.ac.cn> MIME-Version: 1.0 Message-Id: <00010421101502.00773@alan.corp.packetengines.com> Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: This .long stuff dates back to the POWER architecture (IBM) beginnings of PowerPC wherein IBM and later Apple defined a three (or even longer) word table of contents entry for each global entry point. The first word was the pointer to the function, the second word was the pointer to be used for the subroutine's duration for its TOC register value and the third word was some kinda magical language defined extra thingie nobody ever used as far as I know. Effectively, its a larger style function pointer. The boot ROMs on some PowerPC machines (Apple's Open Firmware for example) expect the entry point of a loaded image to have one of these at the entry point location. They simply load the value there and jump to it to start the loaded image. On Tue, 04 Jan 2000, LiuTao wrote: > Hi: > > In linux/arch/ppc/kernel/head.S, what does KERNELBASE mean? > What does the following mean? > ".long TOPHYS(__start),0,0" > > Thanks. > > LiuTao -- Alan Mimms Packet Engines, Inc. Spokane, Washington [99214-0497] USA, Earth, Sol, Milky Way, The Local Group, Virgo Supercluster, U0 Despite the cost of living, have you noticed how popular it remains? -- Steven Wright? ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/