Subject: Re: [PATCH 2/9] powerpc: Add macros to access floating point registers in thread_struct.

From: Scott Wood <[email-masked]>
Date: Wed, 25 Jun 2008 10:34:32 -0500

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