From mboxrd@z Thu Jan 1 00:00:00 1970 From: cgd@broadcom.com To: "H . J . Lu" Cc: ica2_ts@csv.ica.uni-stuttgart.de, binutils@sources.redhat.com Subject: Re: [PATCH] Fix distinction of 32/64bit addresses in MIPS gas Date: Thu, 06 Sep 2001 10:59:00 -0000 Message-id: References: <20010831181657.A17249@rembrandt.csv.ica.uni-stuttgart.de> <200108311711.KAA19709@geoffk.org> <20010831193107.A10362@rembrandt.csv.ica.uni-stuttgart.de> <20010831204556.C17249@rembrandt.csv.ica.uni-stuttgart.de> <20010831143107.A4532@lucon.org> <20010906105014.A32456@lucon.org> X-SW-Source: 2001-09/msg00050.html "H . J . Lu" writes: > > > What is the 32bit address of `foo'? > > > > bit 31 may or may not be set, depending on what exactly you're > > compiling. > > Let me get this. Correct me if I am wrong. It seems that you want > to use 64bit registers in an o32 binary. Am I right? Uh, the way you phrase that, i get the feeling that you think i'm silly for saying "yes." But I think that's probably only because you structure the question unfavforably. I don't think I said anything about "an o32 binary," just a 32-bit ELF binary. "mips64-elf" tools have, historically, generated: * 32-bit ELF * mips3-compatible code (including use of full 64-bit GPRs). Unless you say -mlong64, pointers and longs will be 32-bit, but you'll use full 64-bit GPRs for 'long long'. If you do say -mlong64, you'll get 64-bit pointers and longs, in your 64-bit GPRs. All with a 32-bit ELF format. (And, using R_MIPS_64 to represent pointers in the object files.) I don't really _know_ what ABI it uses. I had always thought of it as "o64", which in my mind was "o32 naively extended for 64-bit GPRs," but really i don't know that that's correct. In fact, I don't really _care_ what ABI it uses. We understand the calling conventions well enough for embedded development use, which is where we're using it. In any case, it _does_ work (or did until recently -- i've not really tried in the last few months with a truly vanilla mips64-elf configuration, since we've got a clone of mips64-elf with a few minor mods which are irrelevant for the purposes of this discussion 8-). You can be sure that if we are, there's no shortage of others doing so as well... cgd