Date: Thu, 26 Jun 2008 22:40:02 +0300
From: Adrian Bunk <bunk@kernel.org>
To: Michal Simek <monstr@seznam.cz>
Cc: linux-kernel@vger.kernel.org, arnd@arndb.de, linux-arch@vger.kernel.org,
       stephen.neuendorffer@xilinx.com, John.Linn@xilinx.com,
       john.williams@petalogix.com, matthew@wil.cx, will.newton@gmail.com,
       drepper@redhat.com, microblaze-uclinux@itee.uq.edu.au,
       grant.likely@secretlab.ca, linuxppc-dev@ozlabs.org,
       vapier.adi@gmail.com, alan@lxorguk.ukuu.org.uk, hpa@zytor.com
Subject: Re: [PATCH 02/60] microblaze_v4: Makefiles for Microblaze cpu
Message-ID: <20080626194002.GC22827@cs181140183.pp.htv.fi>
References: <1214483429-32360-1-git-send-email-monstr@seznam.cz> <1214483429-32360-2-git-send-email-monstr@seznam.cz> <1214483429-32360-3-git-send-email-monstr@seznam.cz> <20080626143623.GC30954@cs181140183.pp.htv.fi> <4863E414.4090303@seznam.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <4863E414.4090303@seznam.cz>
User-Agent: Mutt/1.5.18 (2008-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2179
Lines: 63

On Thu, Jun 26, 2008 at 08:46:44PM +0200, Michal Simek wrote:
> Adrian Bunk napsal(a):
> > On Thu, Jun 26, 2008 at 02:29:31PM +0200, monstr@seznam.cz wrote:
> >> ...
> >> --- /dev/null
> >> +++ b/arch/microblaze/Makefile
> >> ...
> >> +# Work out HW multipler support.  This is icky.
> >> +# 1. Spartan2 has no HW multiplers.
> >> +# 2. MicroBlaze v3.x always uses them, except in Spartan 2
> >> +# 3. All other FPGa/CPU ver combos, we can trust the CONFIG_ settings
> >> +ifeq (,$(findstring spartan2,$(CONFIG_XILINX_MICROBLAZE0_FAMILY)))
> >> +  ifeq ($(CPU_MAJOR),3)
> >> +    CPUFLAGS-1 += -mno-xl-soft-mul
> >> +  else
> >> +    # USE_HW_MUL can be 0, 1, or 2, defining a heirarchy of HW Mul support.
> >> +    CPUFLAGS-$(subst 1,,$(CONFIG_XILINX_MICROBLAZE0_USE_HW_MUL)) += -mxl-multiply-high
> >> +    CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_HW_MUL) += -mno-xl-soft-mul
> >> +  endif
> >> +endif
> >> +CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_DIV) += -mno-xl-soft-div
> >> +CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_BARREL) += -mxl-barrel-shift
> >> +CPUFLAGS-$(CONFIG_XILINX_MICROBLAZE0_USE_PCMP) += -mxl-pattern-compare
> >> +
> >> +CPUFLAGS-1 += $(call cc-option,-mcpu=v$(CPU_VER))
> >> +
> >> +# The various CONFIG_XILINX cpu features options are integers 0/1/2...
> >> +# rather than bools y/n
> >> +CFLAGS += $(CPUFLAGS-1)
> >> +CFLAGS += $(CPUFLAGS-2)
> >> ...
> > 
> > Why are the options not bools?
> > 
> > cu
> > Adrian
> 
> because CONFIG_XILINX_... are 0, 1 or 2 not only y, n.

I understood that.

But _why_ are these options not bools?

In most cases the order of gcc flags does not matter, and it is not 
obvious for me why the order matters here.

> M

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/