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GLIBC 2.16 Brings X32 Support, ISO C11 Compliance, Better Performance
An anonymous reader writes "The GNU C Library version 2.16 was released with many new features over the weekend. The announcement cites support for the Linux x32 ABI, ISO C11 compliance, performance improvements for math functions and some architectures, and more than 230 bug fixes."
if a spreadsheet program uses 4 Gig, find a different spreadsheet program. SERIOUSLY.
Good question. I looked at the linked article and it took me a while to figure out.
x64 CPUs aren't just x86 CPUs with larger memory addresses. They also have more registers, and are guaranteed to support certain additional instructions that aren't necessarily available in an x86 CPU (e.g. SSE). "x32" mode exploits the additional registers & instructions, without actually using 64-bit memory addressing. I think the idea is that it's supposed to allow for most of the benefits of the x64 instruction set without incurring the caching penalties of larger pointers. Honestly I'm not sure how useful that really is.
So, one of the things that has changed in this latest release is that only the ELF binary format is supported. What does this actually mean though? I guess it means they dropped a.out and COFF, but does anyone still use those?
Is this particularly a problem, perhaps for embedded *nix? (I.e. is ELF bigger or worse in resource terms compared to the other two formats?)
As far as I can tell from reading Wikipedia, ELF is much the better format generally, but is it worse in some situations?
Actually, did GLIBC support MS Windows PE format before now (a modified form of COFF)? Or what about the Mac Mach-O format?
GCC can build different file formats, is that also going to change?
I was quite enthusiastic about the idea of something like X32 five or so years ago when it was very rare for programs to want more than 4GB of address space, but now it's far less clear that there's a real advantage.
That same thought struck me as well. At that time, when we were seemingly 'nowhere near 4GB', a x32 ABI would have made sense. But now, by the time it's ready, it's use by date seems to be near, if not already gone.