[PATCH 2/3] ARM: convert to generated system call tables

Geert Uytterhoeven geert at linux-m68k.org
Mon Oct 24 02:25:03 PDT 2016


On Sat, Oct 22, 2016 at 10:23 PM, Robert Jarzmik <robert.jarzmik at free.fr> wrote:
> Arnd Bergmann <arnd at arndb.de> writes:
>
>> On Friday, October 21, 2016 4:48:56 PM CEST Russell King - ARM Linux wrote:
>>> What's the point of the x32 mode?
>>
>> On x86, the motivation is faster code for most use cases that
>> don't need a lot of memory, as the 64-bit opcodes have 16 registers
>> rather than 8 in 32-bit mode but 32-bit pointers have lower
>> cache footprint than 64-bit pointers.
>
> For completness, the second point of x32 AFAIU is the IP-relative addressing
> which is not available in standard 32 bit mode, which improves PIC code. For
> simple not algorithmic code (think Android HAL for example) with many shared
> libraries, it's better in the Hardware Abstraction Layer Libraries, instead of
> the push-to-stack and pop register.

But that's not an advantage compared to full am64 mode, right?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds



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