This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: PATCH: Add regcache_raw_supply_part/regcache_raw_collect_part
On Wed, Feb 3, 2010 at 1:14 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>> Date: Tue, 2 Feb 2010 19:31:31 -0800
>> From: "H.J. Lu" <hongjiu.lu@intel.com>
>>
>> Hi,
>>
>> Intel AVX saves a 256bit YMM register in lower 128bit and upper 128bit
>> separately. This patch adds regcache_raw_supply_part and
>> regcache_raw_collect_part. They will be used in AVX gdb patches . OK
>> to install?
>
> I think introducing these functions would be a mistake. ?If you're not
> careful, you'll end up with a register cache where part of some
> registers is filled with garbage.
They are used
if ((clear_bv & bit_XSTATE_SSE))
regcache_raw_supply_part (regcache, i, NULL,
0, 16, 0);
else
regcache_raw_supply_part (regcache, i,
XSAVE_SSE_ADDR (tdep, regs, i),
0, 16, 0);
if ((clear_bv & bit_XSTATE_AVX))
regcache_raw_supply_part (regcache, i, NULL,
16, 16, 1);
else
regcache_raw_supply_part (regcache, i,
XSAVE_AVXH_ADDR (tdep, regs, i),
16, 16, 1);
I mark regcache as valid after full register is updated. If we get garbage in
regcache, it is a bug.
> I think it is better for the code that fills the register cache, to
> collect the pieces and build the full 256-bit value, and then use
> regcache_raw_supply() to fill the register cache.
>
I can do that with extra memory copy.
--
H.J.