[patch][5/5] powerpc: Add the general support for Embedded Floating-Point instructions

[Zhu Ebony-r57400]

> -----Original Message-----
> From: Christoph Hellwig [mailto:hch at lst.de] 
> Sent: 2007年1月12日 17:52
> To: Zhu Ebony-r57400
> Cc: paulus at samba.org; linuxppc-dev at ozlabs.org
> Subject: Re: [patch][5/5] powerpc: Add the general support 
> for Embedded Floating-Point instructions
> 
> On Fri, Jan 12, 2007 at 01:31:02PM +0800, 
> ebony.zhu at freescale.com wrote:
> > +ifeq ($(CONFIG_SPE),y)
> > +ifneq ($(CONFIG_MATH_EMULATION),y)
> > +core-y				+= arch/powerpc/math-emu/
> > +endif
> > +endif
> >  core-$(CONFIG_MATH_EMULATION)	+= arch/powerpc/math-emu/
> 
> This statement doesn't make any sense.  I guess you always 
> want to build arch/powerpc/math-emu if CONFIG_SPE is set, 
> right?  The proper way to do that is to force 
> CONFIG_MATH_EMULATION in the Kconfig.
> 
> Then again we need a really good explanation why CONFIG_SPE 
> should force the math emulation to be built.
> 
> 

Yes, you are. If CONFIG_SPE is set, I want some files in arch/powerpc/math-emu be built.
The original kernel will build math emulation only if CONFIG_MATH_EMULATION
is set. I don't want to break it.

CONFIG_SPE doesn't force the whole math emulation to be built. If CONFIG_SPE is set,
only the new SPFP/DPFP/VSPFP instructions in arch/powerpc/math-emu will be built,
while the previous FPU instructions won't. This is controlled by Makefile in
arch/powerpc/math-emu

Therefore, what I'm trying to do is to build directory arch/powerpc/math-emu if
CONFIG_MATH_EMULATION or CONFIG_SPE is set. Do you have any idea? 

Thanks.
Ebony