Re: [patch/rfc] align_up, align_down

[Andrew Cagney <ac131313@redhat.com>]

> Hello,
> 
> This patch introduces two utility functions:
> 
>     align_up (v, n);
>     align_down (v, n);
> 
> for [re]aligning addresses vis:
> 
> +   addr = align_up (addr, 8); -- VALUE needs 8 byte alignment
> +   write_memory (addr, value, len);
> +   addr += len;
> 
> +   sp = align_down (sp - len, 16); -- Keep SP 16 byte aligned
> +   write_memory (sp, value, len);
> 
> It then goes through and replaces all occurances of round_up / round_down and align_up / align_down with these globals.
> 
> You'll notice that I chose align_XXX rather than round_XXX.  I think this better reflects the intended usage.  I've noticed a lot of code doing:
> 
>     write_memory (addr, data, len);
>     addr += round_up (len, 16);
> 
> instead of:
> 
>     addr = align_up (addr, 16);
>     write_memory (addr, data, len);
>     addr += len;
> 
> as the former may not result in ADDR having the required alignment.  The PPC SVr4 Altivec ABI, for instance, switches between 8 and 16 byte alignment making the former code very wrong.
> 
> anyway, thoughts?

All positive.

> I'll pick it up in a week,

I've committed it.

Andrew

> 2003-09-12  Andrew Cagney  <cagney@redhat.com>
> 
> 	* utils.c (align_up, align_down): New functions.
> 	* defs.h (align_up, align_down): Declare.
> 	* ppc-sysv-tdep.c (align_up, align_down): Delete functions.
> 	* s390-tdep.c: Replace "round_up" and "round_down" with "align_up"
> 	and "align_down".
> 	(round_up, round_down): Delete functions.
> 	* mips-tdep.c: Replace ROUND_UP and ROUND_DOWN with "align_up" and
> 	"align_down".
> 	(ROUND_DOWN, ROUND_UP): Delete macros.
> 	(mips_dump_tdep): Do not print "ROUND_UP" or "ROUND_DOWN".
> 	* h8300-tdep.c: Replace "round_up" and "round_down" with
> 	"align_up" and "align_down".
> 	(round_up, round_down): Delete macros.
> 	* frv-tdep.c: Replace ROUND_UP and ROUND_DOWN with "align_up" and
> 	"align_down".
> 	(ROUND_UP, ROUND_DOWN): Delete macros.