On 02/02/2012 07:32 AM, Daniel Clark wrote:
On Thu, Feb 2, 2012 at 10:24 AM, Daniel Clark<dclark@pobox.com
<mailto:dclark@pobox.com>> wrote:
Do you mean the n32 or n64 ABI on MIPS 64? I'm assuming n64. FYI there was a
previous n32 google summer of code Debian project, and I think someone got
something working but then lost interest (and I haven't been able to find
the work from that).
http://wiki.debian.org/SummerOfCode2009/Debian_loongson2f_N32_port
Sorry, missed the subject line :-/
n32 does seem to make more sense in most current situations, although I don't
think it works with RAM / swap over 4gb.
n32 is best for most programs as pointers only take 4 bytes wide resulting in lower memory/cache pressure.
We are only talking about user space virtual memory.The 64-bit kernel is (almost?) always n64 and can directly access an map into user space all available memory.
I don't think there is the equivalent of PAE for mips(el), although I could easily be wrong on that. Some 32-bit systems are running into compilation problems on large pieces of software, like libreoffice and firefox - http://news.softpedia.com/news/Firefox-Source-Code-Is-So-Big-It-Hit-the-32-Bit-Virtual-Address-Space-Limit-240112.shtml
We would also want to make n64 libraries available so that programs requiting large virtual memory spaces could use them. Very similar to how x86 systems can have both 32 and 64 bit programs/libraries resident in the same root filesystem and have them interoperate seamlessly.
David Daney