[RFC/PATCH 0/3] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions

Russell King - ARM Linux linux at arm.linux.org.uk
Tue Nov 24 02:42:26 PST 2015


On Tue, Nov 24, 2015 at 11:38:53AM +0100, Arnd Bergmann wrote:
> I suggested using -mcpu=cortex-a15 because there are old gcc versions
> that don't know about -march=armv7ve or -march=armv7-a+idiv yet, but
> that do understand -mcpu=cortex-a15.

That's not all.  The bigger problem is that there are toolchains out
there which accept these options, but do _not_ support IDIV in either
ARM or Thumb mode.  I'm afraid that makes it impossible to add this
feature to the mainline kernel in this form: we need to run a test
build to check that -march=armv7ve or what-not really does work
through both GCC and GAS.

Given that Ubuntu 14.04 LTS suffers with this, it's something that
must be resolved.

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