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Date: Wed, 25 Jun 2008 10:34:32 -0500
From: Scott Wood <scottwood@freescale.com>
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To: Kumar Gala <galak@kernel.crashing.org>
Subject: Re: [PATCH 2/9] powerpc: Add macros to access floating point	registers
	in thread_struct.
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Cc: linuxppc-dev@ozlabs.org, Michael Neuling <mikey@neuling.org>,
	Paul Mackerras <paulus@samba.org>
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Kumar Gala wrote:
>> +/* Macros to workout the correct index for the FPR in the thread 
>> struct */
>> +#define FPRNUMBER(i) (((i) - PT_FPR0) >> 1)
>> +#define FPRHALF(i) (((i) - PT_FPR0) % 2)
> 
> Have you looked at what the compiler spits out here to make sure we 
> aren't getting a divide?  Seems like we could use '& 0x1'.

GCC's not *that* dumb.  However, you may get some unnecessary 
sign-twiddling if "i" is signed.

-Scott