Re: [RFA] SSE registers for cygxin target.

[Christopher Faylor <cgf@redhat.com>]

On Mon, Nov 26, 2001 at 03:43:18PM -0500, Andrew Cagney wrote:
>>On Mon, 26 Nov 2001, Pierre Muller wrote:
>>
>>
>>>-#undef HAVE_SSE_REGS	/* FIXME! win32-nat.c needs to support XMMi 
>>>registers */
>>>+/* Use SSE registers if winnt.h contains information about them.  */
>>>+#ifdef HAVE_CONTEXT_EXTENDED_REGISTERS
>>>+#define HAVE_SSE_REGS
>>>+#else
>>
>>
>>Is it wise to have SSE registers supported based on the compile-time 
>>test?  What if the machine on which GDB runs doesn't have SSE?  Don't you 
>>need a run-time test as well?
>
>In theory?  Yes, definitly.  In reality?  GDB has been avoiding the 
>problem and instead has been hardwiring the configurations.  Sigh.
>
>(This also looks like the PPC and SPARC problem - regcache_collect() is 
>flushing it out ....)
>
>The theory goes something like this:
>
>	o	regcache is made large enough to hold
>		all the registers (SSE in this case)
>
>	o	each target (remote.c, *-nat.c) all supply
>		and/sor collect the registers they have
>		into the regcache
>
>	o	on the other side, core-gdbarch register read/write
>		are (dynamically) configured to display
>		the registers, within the register cache
>
>Things to note:
>
>	o	the core and the target can disagree on
>		which registers are available but _not_
>		on the layout of the regcache.
>
>	o	GDB is going to need to make a pretty good
>		educated guess as to what should be displayed
>		when it starts - there may be no target
>		to tell the truth.
>
>This is why I've been hacking remote.c - more changes to follow.

So, should I hold off accepting this patch, then?  It seems pretty
straight-forward except for this issue.

cgf