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Re: [RFA] SSE registers for cygxin target.
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