This is the mail archive of the
mailing list for the binutils project.
Re: Describing Mips architectures in ELF header flags
- From: Matt Thomas <matt at 3am-software dot com>
- To: Jack Carter <Jack dot Carter at imgtec dot com>
- Cc: "binutils at sourceware dot org" <binutils at sourceware dot org>
- Date: Tue, 17 Sep 2013 15:09:58 -0700
- Subject: Re: Describing Mips architectures in ELF header flags
- Authentication-results: sourceware.org; auth=none
- References: <4CEFBC1BE64A8048869F799EF2D2EEEE01AB545E at BADAG02 dot ba dot imgtec dot org>
On Sep 17, 2013, at 12:48 PM, Jack Carter <Jack.Carter@imgtec.com> wrote:
> I have been bemoaning some use of the ELF header flags for new architectures because of lack of real estate and would like some opinions from interested parties on the list.
> My contention is that we have an EI_CLASS field that is stating that this object is either 32 bit or 64 bit. Thus we don't need to have multiple EF_MIPS_ARCH_ flags such as:
That's untrue. MIPS32/MIPS64 is very different from R3000 or MIPS.
Note only that, you can have O32 binaries compiled for MIPS64.
> We should have had only EF_MIPS_ARCH_R1, and EF_MIPS_ARCH_R2 and have let the EI_CLASS take care of the rest just as we do for EFMIPS_ARCH[1-4]. In odd cases where a 32 bit object contains the 64 bit ISA we have the EF_MIPS_32BITMODE.
anyways, it's too late. code already exists that depends on them and
you can't just break that.
> I understand that the cows have left the barn on the above, but going forward would like to let the EI_CLASS field handle the 32/64 bit difference.
> If you agree with that, I would propose the same for E(F)_MIPS_ABI_ as well. Did we need an O32 and O64 variant? The same for EABI32/64. We have an EF_MIPS_ABI2 that works this way, although it is in the wrong spot in the flags and is taking up a bit field instead of being in the abi enumeration field (sigh).
Again, it's too late.
> I understand that these are enumerated values and not bit fields, but they are finite.
But then, I'd like a EF_MIPS_SOFTFLOAT (or HARDFLOAT) bit.