[Buildroot] [PATCH v3 1/3] arch: add support for Andes 32-bit(nds32)

[Nylon Chen <nylon7@andestech.com>]

Yann, All,

Again, thank you for your comment

On Thu, Mar 21, 2019 at 07:18:54PM +0800, Yann E. MORIN wrote:
> Nylon, All,
> 
> On 2019-03-21 10:36 +0800, Nylon Chen spake thusly:
> > On Fri, Mar 15, 2019 at 06:22:11AM +0800, Yann E. MORIN wrote:
> > > On 2019-03-07 10:11 +0800, Nylon Chen spake thusly:
> > > > This commit provides basic support for the Andes 32-bit(nds32) architecture.
> [--SNIP--]
> > > > +config BR2_nds32
> > > > +	bool "nds32"
> > > > +	select BR2_ARCH_HAS_NO_TOOLCHAIN_BUILDROOT
> > > It would be nice that you provide a package for a pre-built toolchain,
> > > like we have for a few of them, see:
> > > 
> > >     toolchain/toolchain-external/
> > > 
> > > This is not mandatory, but would be a good addition.
> > > 
> > > It would even make the defconfig in your second patch a bit simpler.
> > > 
> > Ok,i will try this method
> 
> As I said: it is not mandatory; we can accept adding the nds32
> architecture without an external-toolchain package.
> 
> It would be _nice_, though, but that can come later, in a followup
> series.
>
Ok, thanks
> > > > +config BR2_ANDES_NDS32_FPU
> > > > +	bool "Enable FPU coprocessor"
> > > > +	help
> > > > +	  You can say y here if your Andes CPU have a Floating-Point Coprocessor
> > > > +	  or if you need FPU support for your user-space programs.
> > > 
> > > So, the situation about FPU is always a bit icky for me.
> > > 
> > > If you say 'n' above, does that mean that you need to do a pure
> > > soft-float build, or that the FP instrcution get trapped an emulated
> > > by the kernel?
> > > 
> > > If the former, then you may want to check whether you need to select
> > > BR2_SOFT_FLOAT (a few packages have conditions based on that).
> 
> This is an important question, but you did not reply to it.
>
Sorry I'm missing this comment.

BR2_ANDES_NDS32_FPU are selector,we can depend on it switch v3 or v3f toolcahin

After we add new defconfig(for v3f),I will be adding BR2_SOFT_FLOAT(-msoft-float) to arch/Config.in.nds32
> > > > +config BR2_GCC_TARGET_ARCH
> > > > +	default "v3"  if !BR2_ANDES_NDS32_FPU
> > > > +	default "v3f" if BR2_ANDES_NDS32_FPU
> > > 
> > > I always find it nicer to have the positive logic come first. Also,
> > > kconfig will stop on the first default stanza which condition is true,
> > > so:
> > > 
> > >     config BR2_GCC_TARGET_ARCH
> > >         default "v3f" if BR2_ANDES_NDS32_FPU
> > >         default "v3"
> > > 
> > Here is my negligence, thank you for your suggestion, i will adopt
> 
> This was not about neglicence on your side, don't worry! ;-)
> 
> It is just about some (mostly-unwritten) conventional rules, with a bit
> of personal preferences, so nothing you could have known.
> 
> This patchset is pretty good, now, and we're now looking at the minor
> details.
> 
> Regards,
> Yann E. MORIN.
> 
> > > > +config BR2_ENDIAN
> > > > +	default "LITTLE"
> > > > +
> > > > +config BR2_READELF_ARCH_NAME
> > > > +	default "Andes Technology compact code size embedded RISC processor family"
> > > > +
> > > > -- 
> > > > 2.18.0
> > > > 
> > > > _______________________________________________
> > > > buildroot mailing list
> > > > buildroot at busybox.net
> > > > http://lists.busybox.net/mailman/listinfo/buildroot
> > > 
> > > -- 
> > > .-----------------.--------------------.------------------.--------------------.
> > > |  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
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> 
> -- 
> .-----------------.--------------------.------------------.--------------------.
> |  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
> | +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
> | +33 561 099 427 `------------.-------:  X  AGAINST      |  \e/  There is no  |
> | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
> '------------------------------^-------^------------------^--------------------'